Science Seminar, presented by the Math, Science, and Engineering Division, Annandale Campus and also supported by Lyceum

"The Scientific Basis of Music"
Herbert A. Smith, Director Jazz Studies, Northern Virginia Community College.
Friday, November 20, 2009, CE Forum, 12 noon - 1pm

This presentation will focus on music and its essential relationship to science. It will explore areas, aspects and elements of music that most reasonably could be termed the science of music. The talk will also illuminate unique principles, concepts and procedures shared within the sciences as well as music. It will highlight the benefits of music study and practice in the intellectual and philosophical development of the educated and enlightened individual.

Professor Smith has taught at NOVA since 1976 and has performed with notable local and internationally known jazz musicians throughout his long career in music. He has taught a variety of courses including Jazz Improvisation, History of Music, Music Theory, Composition and Music Appreciation. Before he joined the faculty at NOVA he taught at Howard University and Southern Illinois University, hosted two radio jazz shows and was in the US Air Force band for three years. Herb Smith has a passionate interest in history, politics, economics, philosophy and the study of world cultures.

All students, staff, and faculty are cordially invited.

Labels: meetings, music, nova

Whew! A busy day at the Geological Society of America meeting in Portland, Oregon. I started off the day in the two-year-college session, culminating (for me, anyhow) in my talk about the role that field trips play in my geology classes at NOVA. I believe in spirited presentations, so I moved away from the lecturn and spoke extemporaneously about my images and data, and the talk was well-received by the audience -- or at least that portion that chose to tell me what they thought. After the talk, I was really tired out (I hadn't realized I was stressing about the talk, but apparently I must have been.) I went back to the hotel and took a shower, dealt with some mortgage stuff (I'm buying a condo in DC), and then semi-refreshed, headed back to the fray at the Convention Center.

I've met another several geobloggers: Brian Romans and Kim Hannula. Geoblogger Lockwood Dewitt sent me a rock (natrolite in calcite! likely from a pillow basalt!) via roaming geoblogger "Silver Fox." Cool. I dig it. I had some people come up to me out of the blue and tell me that they read this blog, and that is super cool to hear. Thanks!

In the afternoon, I went to a few sessions about volcanism and the end-Permian extinction, history-of-geology, and I forget what else.

In the late afternoon, the beer began flowing. I started off at the W.W. Norton publishing company's beer bash, where I brushed shoulders with Walter Alvarez, met the author of my Physical Geology textbook, Steve Marshak, and chatted at length with Bob Lillie of Oregon State University about getting the National Park Service better educated about their geological resources. Then it was off to the AGI reception, where I won a bottle of wine and got to chat with David Williams, author of Stories In Stone. Meg Sever, the editor of EARTH, with whom I've e-mailed a zillion times, but never met. Turns out Meg went to William & Mary, like me (and Jessica Ball, also at the AGI reception), so the three of us trooped upstairs to the William & Mary alumni reception. It was good to see Brent Owens, Heather McDonald, and Chuck Bailey there, as well as other W&M geology grads (including Graham, who reads this blog! Hi Graham!).

The evening's final event was the much-ballyhooed geoblogger's meet-up. At 8pm, about fifteen of us assembled at Tugboat Brewing Company, a cozy, charming little pub in downtown Portland. Every time someone walked through the door, a rousing, "Yeeeaaaahhh!!!" cheer went up. And every time someone left, they got booed! It was terrific fun meeting everyone that I've had these online geoblogging relationships with over the past ~1.5 years, and I think a good time was had by all. I'll put some photos up later... [Other online reminiscences about the meetup: Chuck and Jessica.]

Labels: books, geology, meetings, national parks, nova, oregon

I've just submitted a list of the classes I intend to teach for summer 2010. Here they are on NOVA Geoblog, before you can access them in the official Schedule of Classes...

GOL 135 (070N) The Bedrock Geology of Washington, DC. HYBRID COURSE: pre-trip reading, field study and post-trip report. One-day field trip Saturday, June 12. Rain date: Sunday, June 13. Important pre-trip logistical information and preparatory readings located online. This trip will focus on the land upon which the capital city is built, including exposures in Rock Creek Park, Georgetown, and Adams-Morgan. Includes discussion of oceanic sediments, the Rock Creek shear zone, igneous rocks emplaced during Appalachian mountain-building, Cretaceous river gravels, dinosaur bones and recent faulting. Students will be evaluated with a field trip report which will be completed after the trip itself. NOTE: This trip involves moderately strenuous hiking on forest trails. Meet in back of the CT building at 9:00 a.m.; Return by 7:00 p.m. For information about meeting time/place or other questions call (703) 323-3276 or email cbentley@nvcc.edu
HYBRID course
Additional info online

GOL 295 (4 credits) Regional Field Geology of the Northern Rocky Mountains: July 10 to July 25, 2009. Pre-trip meetings Wed. June 9 and Wed. June 23, 6:30pm, in CS 217. Western Montana and Wyoming showcase tectonic, sedimentary, geomorphic, and volcanic features which provide world-class examples of geologic processes. Students in this course will complete field studies of locations in Yellowstone and Glacier National Parks, as well as several other field sites. The course will involve VERY STRENUOUS outdoor physical activity: Students are expected to hike several miles at high elevations in rough mountainous terrain in order to accomplish course objectives. Airfare, lodging, and transportation are covered in the approx. $1400 course fee (does NOT include tuition). For up-to-date information and a complete itinerary, see the course website or contact the instructor at cbentley@nvcc.edu or (703) 323-3276.
Extra fee
Instructor permission required
Additional info online

GOL 299 (071N) (2 credits) Snowball Earth. June 14-19, 2009. HYBRID COURSE: pre-course reading, lab, field study and post-course report. An episode of glaciation 700 million years ago, dubbed Snowball Earth, may have provided for the evolution of multicellular life. The Snowball Earth glaciations stretch our conception of the limits of climate change: the ice apparently reached from the Earth's poles to its equator! Scientists infer that the runaway freezing event was only ended due to volcano-induced global warming. This course examines the geological, chemical, and biological evidence for Snowball Earth, and includes a field trip to local "Snowball" deposits. Course meets four times: three evening sessions (6pm-9pm) in CS 217 and all day on a Saturday (9am-5pm). The schedule is: Monday June 14 (lecture), Wednesday June 16 (lab), Friday June 18 (discussion), and Saturday June 19 (field trip). For further information call (703) 323-3276 or email cbentley@nvcc.edu or go to the course website.
HYBRID course
Additional info online

Anyone in the Northern Virginia area who's interested in any of these classes, drop me a line!

Labels: dc, field trips, geology, montana, nova, snowball earth, teaching

NOVA's accurately-named student newspaper, Fortnightly, is now online. New issues every fortnight (two weeks)!

Labels: news, nova

Friday, October 23, 2009, CE Forum
12 noon - 1pm

"Community-Based Environmental Action"

Chris Bright, President and Co-Founder of the Earth Sangha, a non-profit environmental group

The Earth Sangha is a Buddhist environmental group based in Fairfax County co-founded by Chris and his wife, Lisa Bright, to work with volunteers on ecologically significant restoration projects in natural areas. Every year over 500 volunteers donate more than 10,000 hours of their time to the Sangha's restoration projects throughout northern Virginia. Volunteers have built the Sangha's Wild Plant Nursery, DC region's most comprehensive local-ecotype native-plant propagation center. (Local ecotypes are local, wild native-plant populations; the use of local ecotypes is a standard best practice in restoration because that helps to conserve the genetic diversity and local adaptation in the species planted.) The Earth Sangha is also a kind of low-tech innovator in the control of invasive alien plants; such plants are a major threat to local natural areas. In 2006, the Sangha transplanted a version of its community-nursery approach to the Caribbean island of Hispaniola. The Sangha's Tree Bank / Hispaniola program works along a portion of the Dominican Republic - Haiti border, where it helps impoverished farmers improve their incomes and restore patches of native forest on their lands.

Chris Bright will describe the Earth Sangha's work, the rationale behind it, and its implications for the conservation agenda. Before founding the Earth Sangha, Chris was a Senior Researcher at the Worldwatch Institute, a think tank that tracks global environmental and social trends. He is the author of numerous articles and one book, Life Out of Bounds: Bioinvasion in a Borderless World, the first global, interdisciplinary study of biological invasion written for a general audience.

Labels: action, environmental, meetings, nova

Today I took a group of students to Sideling Hill, a syncline in western Maryland. Here are a few photos from the trip. All photos by my iPhone, via Facebook (which is why the quality is lower than my usual standards):

The group all kitted out at the Sideling Hill Visitor's Center (which was closed due to budget cuts in Maryland):


Jared points out fast-weathering shale layers betwixt slower-weathering sandstone layers:


Diamictite outcrop on the far western side of Sideling Hill:


More diamictite... enigmatic sediments...

Labels: maryland, nova, primary structures, sediment, structure, teaching, valley and ridge, weathering

My colleagues in NOVA's biology department were featured in today's Washington Post, which includes some photos of my building (the Shuler Building) and one of our labs. The point of the article is that community colleges in the DC area are adding classes like crazy to keep up with demand. The weak economy is blamed for the uptick in enrollment. Our student population increased by about 10% this semester. NOVA's numbers tower over other area schools:

Hat tip to Doug Dupin for alerting me to this piece!

Labels: nova, teaching

My colleague Ken Rasmussen and I were among ten faculty featured in a video that NOVA-Annandale Provost Barbara Saperstone commissioned to brag to the NOVA Board about all the cool stuff going on at her campus. If you're interested in watching the video (~17 minutes), it can be downloaded here. If you're only interested in the geology portion, fast-forward to 14:57 or so. (They saved the best for last.) Enjoy!

Labels: field trips, movies, nova, teaching

The first of our monthly science seminar series is coming up at the end of the month:

"Cameras we cannot picture"
Dr. Ravi Athale, Senior Principal Scientist, The MITRE Corporation
Monday, September 28, 2009, Ernst Center Forum, 12 noon - 1pm

Abstract: The world of imaging has evolved from its humble origins as a pinhole camera to its current incarnations of very large (Hubble Space Telescope) and very small (pill cameras that one swallows). Last 10 years, in particular, has seen more rapid growth in our ability to record static and moving images than anytime in human history. This has been enabled by replacing film with semiconductor devices for recording imagers. Dr. Athale argues that as dramatic as this progress has been, the future will bring even more startling and unimaginable changes due to the integration of imaging with equally spectacular progress in computing, communications and storage technologies.

Ravi Athale is Senior Principal Scientist and Department Head, Emerging Technology office at the MITRE Corporation. Over past 30 years he has worked as a scientist, educator and manager in government, academic and industrial institutions. In 2007, he received Leadership Award of the Optical Society of America and Secretary of Defense Medal for Exceptional Public Service. In addition, he is a co-author of a high school engineering textbook published by Prentice-Hall and is a co-founder of company that develops consumer products based on computer generated holograms.

Please join us, if you can!

Labels: art, meetings, nova, science and society, tech

(Parts 1, 2, 3, 4, 5, & 6 of this series...)

Today's episode: The route down the mountain, and the long way back to camp.

After our "summit" of the arete between Hanging Canyon and Cascade Canyon, we begin carefully picking our way back downhill, switching between talus piles and snowfields, and back again:




We popped over the threshold, and started dropping down towards Jackson Hole. As the sun was dropping lower and lower in the sky to the west, we were pretty much in shadow from here on down... but the light still lingered on the highest peaks, like Teewinot Mountain, Mount Owen, and the Grand Teton itself:


By the time we got all the way back down to Jenny Lake, the sun was pretty much gone. However, it was illuminating a tall cloud north of us, sitting atop the Yellowstone area. We joked that this was the big one: Yellowstone had finally blown up and the orange color we were seeing wasn't "alpenglow" but incandescence from the long-awaited eruption of the Yellowstone volcanic center...


It wasn't, though. Just a little jest to take our minds off the fact that we had missed the last ferry across Jenny Lake, and so that meant adding an additional "2" (it sure felt more like 3) miles to our hike. As darkness closed in, we hoofed it along (only Pete had been prepared enough to bring a headlamp). For me, a highlight of this long slog came when Joel and I spotted an animal I'd heard of but never actually seen before: a pika! They are very, very cute animals that live in talus piles and make little squeaky noises. But they're quite elusive, at least in my experience. I've seen plenty of marmots and other alpine rodents, but this was my first Ewok pika.

We eventually got back to the vehicle and rolled back to camp, getting there about 10pm. We wolfed down some dinner, quenched our thirst, and sacked out. What a great day! In spite of being dog tired, I felt mentally rejuvenated and ready to take on the second half of the Rockies trip.

This post concludes the Hanging Canyon series. Thanks for coming along!

Labels: mammals, nova, travel, volcano, wyoming, yellowstone

(Parts 1, 2, 3, 4, & 5 of this series...)

As we were climbing up a steep snowfield, we saw something that made us rush up to the top:


Interpretive sketch:

At first, we thought this was a big isoclinal synform that was cross-cut by a ptygmatically*-folded granite dike, but closer inspection at the "axis" of the "fold" revealed that it was instead just the trailing edge of a big boudin. It pinched down and then swelled again in the downward direction, hidden in this photo by the snowpack. Not quite as cool... but still pretty cool. And I can never say no to ptygmatic* folding, regardless of the setting.

This is also kind of cool:

What you're looking at here is a gneiss, with alternating layers of coarse-grained mafic and felsic minerals. The view of the photo is orthogonal to the plane of foliation, but the boulder has been weathered so that in some places the uppermost mafic layers has been worn away. There's one spot where you can "see through" the mafic layer into the underlying felsic layer (upper right) and another spot where there's a little isolated scrap of the mafic layer where the surrounding material has been weathered away. This reminded me of a larger-scale phenomenon where the same thing happens to thrust sheets: an erosional hole through a thrust sheet into the rock beneath is a tectonic "window" or "fenster" (German for window). An erosional remnant of a thrust sheet is a "klippe." The Grandfather Mountain Window in North Carolina is an example of a fenster. Chief Mountain in Glacier National Park, Montana, is an example of a klippe. So this little boulder gives us a nice physical analogue for regional-scale tectonic/erosional features.

Ahh... what cool stuff to see and think about. But the sun was setting, and we had to head back to camp and the rest of our team... Tomorrow: the story of the long hike home.

________________________________
* Really, more of a "cuspate-lobate" fold, without the parallel limbs that make for a truely ptygmatic fold.

Labels: analogies, art, montana, national parks, north carolina, nova, structure, travel, wyoming

(Parts 1, 2, 3 & 4 of this series...)

Today we'll look at some of the structural geology photos I took in Hanging Canyon, Teton National Park, Wyoming. These are all rocks of the Archean-aged Wyoming Terrane (or "Wyoming Craton"), one of the most ancient pieces of crust that make up the quilt-like North American continent. They include both metamorphic and igneous rocks that have been suffered enjoyed being deformed by tectonic processes.

Labels: archean, igneous, metamorphism, national parks, nova, structure, travel, wyoming

Parts 1, 2, & 3 of this series are at these links.

Today and tomorrow, I'll share some of the gorgeous Archean rocks that are exposed in Hanging Canyon, Grand Teton National Park, Wyoming. Today: the igneous stuff. Tomorrow: the structural stuff.

There were many pegmatite dikes that we saw along the hike. Here's a lovely one cutting across the metamorphic host rock:


A close up of some big muscovite "books" in the pegmatite:


A couple of parallel pegmatite dikes cutting across granite:


Here's the largest single feldspar crystal I've ever seen in the wild. The crystal starts to the left of my boot and continues for over a foot to the left of that. Its color varies between bluish gray and whitish. Where the left-most and most prominent blue stripe is, that's the edge of this monster megacryst:


Huh... Only four "igneous" photos... I guess I'll make up for that with tomorrow's structural geology post about Hanging Canyon... I have about forty photos of folds and boudins and what-not to share...

Labels: archean, granite, igneous, minerals, national parks, nova, structure, travel, wyoming

Today, picking up where we left off yesterday, some images from the hike upwards from Jenny Lake to Hanging Canyon...

Joel and Ken take a breather:


The approach to the final lip of Hanging Canyon:


A view down over Jenny Lake and Jackson Hole:

Jenny Lake is dammed by an end moraine (which is characterized by pine trees growing on it here, making for a nice dark stripe around the lake).

We could also see across Jackson Hole to the Gros Ventre valley, where the Gros Ventre lanslide scar was readily visible:


...And lastly, the view to the north, over Jackson Lake (with String Lake in the middle distance):


More tomorrow about what we found once we got up into Hanging Canyon itself... (Hint: it's white and cold and fun to ski on...)

Labels: glacial landforms, mass wasting, national parks, nova, travel, wyoming

One of the highlights of this past summer's Northern Rockies field course was an afternoon set aside as a "choose your own adventure" hike in Teton National Park. Some students opted for Cascade Canyon; others climbed Blacktail Butte. Four of us wanted something really challenging, so we chose Hanging Canyon at the recommendation of my friend Amy Manhart, who lives in Jackson and knows the Tetons like the back of her hand.

We took a ferry across Jenny Lake along with the Cascade Canyon Crew, and then started climbing up. A thunderstorm rolled up Jackson Hole, with much ominous booming and lightning, but we didn't get hit with the storm directly. The climb was very steep, but we entertained ourselves along the way with a geological conundrum: We discussed how best to interpret a hypothetical piece of float that is half granite and half diorite: Is it more parsimonious to guess that the granite represents an intrusion or an inclusion? The implications for the relative dates of the two units are huge: if the diorite is an intrusion, it's younger than the granite. If the diorite is a xenolith (an inclusion) within the granite, then it's older than the granite. Consider the possibilities:



Ultimately, there's no answer to this question without finding an outcrop of the rock in situ, which is why it's entertaining to consider when you're slogging up a 2000 foot hillside. My co-instructor Pete Berquist and I upped the ante by each doggedly defending one of the two indefensible interpretations and sticking to it for the sake of argument. Pete was the xenolith man, whereas I came down fully on the side of the dikes. Our students Joel and Ken were "fortunate" enough to listen to Pete and I bicker about the relative merits of our favored interpretations. Rest breaks came whenever either Pete or I found a boulder along the hillside that showed evidence to support our position. We would stop to consider it, catch our breath, and the resume the uphill climb and the argument. The bad weather passed and the day was beautiful. We were unencumbered by the need to reach a conclusion or acknowledge the obvious: the best interpretation is that such half-&-half clasts "cannot be interpreted."

Here's Pete posing with an obvious dike (I forced him! Ha!):


Here's me posing with an obvious xenolith (Oh well, fair's fair...):


We had a similar ongoing "argument" on the trip about the merits of "Tertiary" versus "Paleogene." I think it keeps students amused to see their professors going back and forth over geologic ideas -- surely if these fellows spend this much energy and thought discussing some geologic question, it must be valid and important... ...right?

More on the Hanging Canyon hike tomorrow...

Labels: archean, geologic time, igneous, national parks, nova, structure, travel, wyoming, xenoliths

Last night, I took a group of Honors students to the United States Geological Survey's National Center in Reston, Virginia, for a public lecture by Bruce Molnia about Alaska's disappearing glaciers. The talk was all well & good, but a nice little surprise came afterwards, when Jared noticed a display in the lobby of the Dallas Peck Memorial Auditorium:

That's the classic "ancient Chinese seismograph" featured in so many introductory geology textbooks as the lead-in to their chapters on earthquakes and seismology. Pretty cool to see it in the flesh brass.

The way it works is that each of the little dragon heads projecting off the urn had a little brass ball in its mouth. If it got shaken by an earthquake, that little brass ball would pop out and into the waiting mouth of the little brass frog down below. The frogs aligned with the wave propogation direction would be the ones to be "fed." This implication of the temblor's source direction would allow authorities to direct scouts and relief operations to the appropriate corner of the dynasty.

Neat!

Labels: alaska, earthquakes, gear, glaciation, nova, rept, teaching

We just got a new position approved for our campus Science Learning Center!

Job Title: Science Learning Center Coordinator

Job description: Assist in setting up and coordinating the Science Learning Center. Provide lab help and advising outside of regularly scheduled class and labs. Provide help to science faculty for individual supervised classess, laboratories & undergraduate research. Work with laboratory assistants in reviewing & updating experiments. Organize study sessions and open study hours. Gather needed equipment and supplies; properly store and inventory these materials. Work with the Math, Science, and Engineering faculty, staff, and steering committees.

Degree Requirement: Bachelor’s Degree in Science, or equivalent training and experience. Master’s preferred.

Salary Range: $35,693-$53,345

Apply at our Human Resources page.

Labels: jobs, nova, teaching

Over the summer the rest of the geology department and I moved into our new home, the Shuler Building (CS) on the Annandale campus of NOVA. As part of our refurbishment, I got a nice new display case which is prominently displayed in the hallway of the second floor of CS, just down from our lab. For its inaugural display, I put together a collection of photos and samples from this summer's Rockies course. I think it looks pretty good:



If you're on campus, stop by and check it out!

Labels: gear, geology, montana, nova, teaching

Rockies co-instructor Pete Berquist was quoted in a nice little article appearing recently in Thomas Nelson Community College's internal newsletter. Here it is.

Labels: field trips, montana, nova, teaching

This was composed by Rockies student (and new full-time NOVA math faculty!) John Weidner. It's the one he sung for us in the airport on our way home from Montana (resulting in this photo):

The Geology Song

to the tune of the theme from the movie The Bridge on the River Kwai
(MP3 download)

Geol - ogy: we study it.
We think - that we know quite a bit.
Mountains - shoot up like fountains.
We know that sandstone's - a grand stone - So's chert!

Granite - a rock that forms a lump.
Landslide - that's what we call a slump.
Gravel - in streams does travel.
We know that claystone's - a gray stone - So's chert!

(triumphally)
The layered rocks, - that everywhere here we see,
are defined through stratigraphy.
And ig - neous rocks we see here too,
wi - i - ith-out a volcano in view.

Oh, Hutton - he looked at Siccar Point
Lyell - he said time's out of joint
Callan - and Pete no failin',
have taught us limestone's - a fine stone - So's chert!

Labels: geology, humor, music, nova

Please forward this post to anyone who you think might be interested. Thanks!

The Annandale campus of NOVA has an opening for an instructor to teach a Monday / Wednesday evening section of Physical Geology this semester. The class runs from 6:30pm until 9:20pm on Monday nights (lecture) and from 6:30pm until 9:20pm on Wednesday nights (lab). It is a four-credit course.

Applicants should have at least a master's degree in geology or a related Earth Science field. The general starting salary range for this position is between $730 and $862 per credit hour. The specific salary for each position will be calculated based on the selected individual's academic preparation and experience. Apply by sending a resume and expression of interest to Craig Jensen, Assistant Dean for the Physical Sciences, at cjensen@nvcc.edu.

I can provide any and all lecture PowerPoints, tests, and ready-to-go lab exercises for the instructor, if they so wish. We can make this really easy! (The instructor also has complete academic freedom to teach the course as they see fit.) NOVA students are diverse and fun, and this is an excellent opportunity to try out some teaching if you've never done it before, or if you're just looking to earn a few extra bucks sharing your knowledge.

Please don't hesitate to contact me or Craig with any questions!

CB

Labels: jobs, nova, teaching

Imitating the detail of a tartan plaid, perhaps?



These perpendicular cross-cutting dikes were observed by NOVA associate professor of geology Victor Zabielski on a trip this summer to Scotland. Thanks for sharing, Victor!

Labels: igneous, nova, scotland, structure

All photos in this post by Rockies student Charlie Corrick.

Obstacle in the road...


Tetons...


Charlie and Jared on Blacktail Butte:


Luke on Blacktail Butte:


Charlie, Luke, and Jared on Blacktail Butte:


Checking out the fault scarp of the Hebgen Lake Fault, north of Hebgen Lake:


Examining the Grinnell Formation for the first time:


Looking down the St. Mary Valley, Glacier National Park:


Stromatolites in the Helena Formation, Glacier National Park:


Victoria points out the contact of the Purcell Sill with the surrounding Helena Formation (limestone), Glacier National Park:


Callan points out the contact of the Purcell Sill with the surrounding Helena Formation (limestone), Glacier National Park:


Pete and Joel point out the contact of an apophysis of the Purcell Sill with the surrounding Helena Formation (limestone), Glacier National Park. Notice that the sill cuts across stratification down by Joel's legs.


At the Bozeman Airport on the way home, John entertains us with geology songs he composed, which cracked up the instructors:

Labels: glacial landforms, montana, national parks, nova, proterozoic, travel, wyoming

Following on this morning's video from Jason, here are a few more Rockies class final projects:

Ringing Rocks (Bob)
Lewis & Clark Caverns (Charlie)
Gros Ventre Landslide (Chris)

Labels: montana, nova, teaching, websites, wyoming

Labels: art, evolution, nova, teaching

WHAT: Top Ten Things You Should Know About Climate Change

WHEN: Tuesday, August 4, 5:30-8:00 PM; program begins at 6:15 PM.

WHERE: The Front Page Restaurant, 4201 Wilson Blvd., Arlington, VA, Located near Ballston Metro on the ground floor of the NSF building. Parking is available under the NSF building or at Ballston Common Mall.

WHO: Keith Dixon, Research Meteorologist and Climate Modeler, NOAA's Geophysical Fluid Dynamics Laboratory, Joe Witte, Meteorologist, Newschannel 8

HOW: Special 1/2 price burgers start at 5:30 PM. Please come early to order table service and socialize. Short presentation begins at 6:15 PM, followed by Q&A. No science background required—only an interest!

Cafe Scientifique is free and open to the public. Register online here.

ABOUT THE TOPIC: In the coming decades, scientists expect climate change to have an increasing impact on human and natural systems. In a warmer world, accessibility to food, water, raw materials, and energy are likely to change. Climate change will also affect our weather, human health, biodiversity, economic stability, and national security. Come learn the top ten things you should know to know about climate change.

SUPPORT THIS CAFE: The Ballston Science and Technology Alliance, a nonprofit organization, is the sponsor of Cafe Scientifique Arlington. Since April 2006, the goal of Cafe Scientifique has been to make science more accessible and accountable by featuring speakers whose expertise spans the sciences and who can talk in plain English. Cafe is held each month on first Tuesdays at the Front Page in Arlington. Please go to www.arlingtonvirginiausa.com/bsta and contribute. Help keep Cafe open and free to all!

COMING NEXT MONTH: September 1, BioDiversity: How Special We Are! Dave Harrelson and Susan Jewel, Biologists, Endangered Species Program, U.S. Fish and Wildlife Service SPECIAL BSTA PROGRAM: August 25, 4:15 PM at Room 110 NSF, Climate Change Communication 2.0, Ed Maibach, Director of George Mason University's Center for Climate Change Communication. Register online here.

For more information contact Kaye Breen, ballstonscience@yahoo.com, visit www.arlingtonvirginiausa.com/bsta or join us on twitter: http://twitter.com/sciencecafeva or facebook: http://www.facebook.com/pages/Ballston-Science-and-Technology-Alliance/116954825970.

Labels: climate change, dc, meetings, nova

My colleague Ken Rasmussen (the other full-time geology professor at NOVA-Annandale) takes issue with George Will's most recent climate-change-denying column for the Washington Post.

Labels: climate change, dc, environmental, global warming, nova

Labels: art, dc, field trips, geology, nova

It's been busy round these parts. My apologies for the lack of posts this past week.

I leave tomorrow for Montana, and I'll have limited e-mail access while out there. I'll do my best to post when I can, but it will likely be more on the ~weekly timescale rather than ~daily.

On the agenda: (1) Bahama Montana, (2) present and defend my MSSE capstone project, and (3) lead my Regional Field Geology of the Northern Rockies class for NOVA.

More later...

Labels: blogs, montana, msse, nova, travel

Two cool courses taught by my esteemed colleagues... If you're local and love rocks, you should enroll in both of these!

Birth of the Appalachians. GOL 135-003A. Saturday, June 20. A one-credit field course to investigate the paleogeography of Virginia, prior to the initial uplift associated with the Appalchian Orogeny. We will be specifically looking at rock outcrops representing the pre- and post-uplift topography and environments, based on evidence in the present Shenandoah Valley of Virginia. Light hiking and roadside geology. Contact Victor Zabielski for more information: vzabielski@nvcc.edu

Mid-Atlantic Field Geology (for educators and interested others). GOL 295-050N. A coherent series of one-day regional field trips, plus on/off-campus lectures and labs on Thursdays (2 - 8:20 PM) during second summer session (also two Saturdays: 7/18, and 8/1). This is an introductory-level, four-credit lecture/lab/field hybrid course, tailored to educators and interested others. It considers local outcroppings of the mid-Atlantic Coastal Plain, Piedmont, Blue Ridge, and Valley and Ridge, as natural classrooms for the demonstration of geologic principles, the study of earth history, and the collection of demonstrative hand-samples. Specific meeting places/times and preparation will be sent via student VCCS email addresses & Blackboard. Class # 12594. If more information is necessary, feel free to email: krasmussen@nvcc.edu

Labels: field trips, geology, nova, virginia

On Saturday's Bedrock Geology of Washington, DC class, my students and I had the good fortune to stumble upon two geologists out doing field work: Tony Fleming, lead author of the geologic map of the Washington West quadrangle, and Steve Self, senior volcanologist with the Nuclear Regulatory Commission. They were out looking at the Sykesville Formation at Chain Bridge Flats, assessing a potential reinterpretation of the unit.

Fortunately, they were willing to take a little time and discuss their findings with the students. Here's a couple shots of Steve talking to the group:




I joined Steve and Tony in the field yesterday (Monday) too, looking at some outcrops on the other side of the river, and trying to make sense of them. Fun stuff! More on that at a later date...

Labels: dc, field trips, geologists, geology, igneous, metamorphism, nova, piedmont, sediment, volcano

There's a brief blurb (with a few photos) on the first few pages of this week's Intercom about the NAGT meeting last month on the Loudoun campus, and Ken Rasmussen's award.

Labels: geologists, meetings, nova

So, it's a month until my Rockies class starts. I've been encouraging all the students to get in shape, because the high elevations, rough terrain and multimile distances we'll be hiking in Montana and Wyoming could really kick an east-coast flatlander's arse. So we've scheduled a few training hikes to help everyone physically prepare for the Rockies experience. Last weekend, we did a 5.5-mile circuit up the steep Little Devil's Stairs trail in Shenandoah National Park. I was joined by five Rockies students + one of their kids. Here's a map of the loop we did:



Here's a few photos of the hike, and the geology we encountered along the way:



John poses next to some jointed columns in the Catoctin Formation, a Neoproterozoic rift-related series of flood basalts (subsequently metamorphosed during Alleghenian mountain building).


End-on view of one of the columns:


Overhanging cliff showing columns weathering out along jointed surfaces:


Bob poses next to a cliff, helping me demonstrate how difficult it is to take a well-exposed photo in the jungle of the Virginia hardwood forest:


A wiggle in some columns:


Jared thought these columns were better than the first ones he saw, at Old Rag Mountain.


Here's me with a fifteen-foot-long section of columns, indicating that the flow from which this boulder was derived must have been at least fifteen feet thick, maybe more:




But it wasn't all columns. There was also a lot of column-less massive Catoctin Formation, and some nice inter-flow conglomerates which are interpreted as stream deposits that developed atop a cooled flow before the next flow erupted. These conglomerates imply a reasonable amount of time passed between successive eruptions of the Catoctin flood basalts. The lichens obscure the rock, but note for instance the fingernail-sized chunk of greenstone an inch above my hand:


More chunks in the conglomerate:


And more:


Jared guards the way forward:


The view from the top:

Labels: basalt, iapetus, igneous, metamorphism, nova, primary structures, proterozoic, sediment, shenandoah, structure, teaching

Article in today's Post: "Community Colleges Get Student Influx In Bad Times"


"One-quarter of the enrollment growth at all two- and four-year colleges in Virginia over the past year occurred at Northern Virginia Community College."

Labels: economics, nova

And now, a few images from April's Environmental Geology class field trip. We made three stops: (1) a large coal-fired power plant in Maryland, (2) Westmoreland State Park in Virginia to look at coastal erosion, and (3) Prince William Forest Park in Virginia to look at pyrite emplacement and acid mine drainage.

Here's one of the bluffs on the Potomac River at Westmoreland:

Note the recent pile of breakdown in the middle of the bluff where all the water seepage is, and also the orange trail as soil from the uppermost bluff has marked another mass wasting event's passage down to the river.

These are Miocene-aged sedimentary layers known as the Calvert Formation, part of the Coastal Plain. In places, the gray clay has been altered along fracture surfaces, as shown by these orange stripes criss-crossing one another. My toes for scale:


The students spent some time searching for fossils: this is an area where lots of shark teeth are found. We didn't have much luck, but after a long cold winter, it was nice to be standing in the warm sunshine and water:


At Prince William Forest Park, we hiked down to the Cabin Branch Pyrite Mine to look at the massive denudation there due to acid mine drainage, and we also spent some time poking around for treasures, in this case chunks of pyrite:


We had better luck than at Westmoreland...




...But of course we were in a national park at Prince William, so we left the pyrite where we found it. (Westmoreland, in contrast, allows you to keep any fossils you find in loose sediment: that figures, eh?)

I'd like to say that the group of students I had in Environmental Geology this past semester was terrific, one of the best groups I've worked with in a long time. Maybe it was because the class was discussion-focused, or maybe it was the cookies we ate every Tuesday night, but it was a great experience for me, and I'm looking forward to teaching the course again. Thanks, everyone, for making it so much fun!

Labels: coastal plain, environmental, field trips, maryland, miocene, nova, ore, piedmont, virginia

Last Saturday was my Field Studies in Geology trip to Shenandoah National Park. Here's a few shots from the day's geologizing...

Garnets in the Pedlar Formation granite gneiss, oldest rock in the park at ~1.1 Ga.


Meta-basalt columns of the Catoctin Formation (photo by Mathina Calliope):


At the end of the trip, I have the students order a series of strips of paper with different geologic events in the park's long geologic history. They have to figure out the proper order based on what they learned that day:





Lastly, a group photo overlooking the Browntown Valley:

Labels: field trips, metamorphism, minerals, national parks, nova, shenandoah, teaching

These videos were shot by NOVA's videoman extraordinaire Richard Attix, who helped me immensely this morning by splicing together these movies for use in my MSSE capstone presentation at the end of next month. Enjoy!

Teaching on the Billy Goat Trail (a blend of instructor-focused lecture and student-focused exploration):

Hiking on the Billy Goat Trail:


End-of-trip activity - "Ordering Geologic Events":

Labels: field trips, nova, piedmont, teaching

Hey there Northern Virginia-area readers,

Our readers in Kansas, California, Colorado, London, India, & Australia* can't do what you can do.

Only YOU can sign up for NOVA summer field geology courses.

Check them out. See you out there in the real world.

Sincerely,

Callan

* = representative sample only, chosen for geographic diversity. No slight intended for the many other readers in equally far-flung, equally worthy locations.

Labels: field trips, nova, teaching

My former Honors student Laura graduated from NOVA a year ago and transferred to the University of Virginia. But during her second semester at UVA, she joined the SEA Semester program, and sailed around the world.

During Honors presentations this year, current Honors student Kristen (and friend of Laura's) brought in a gift from Laura: a collection of rocks and photos from Namibia, one of their ports of call on the trip.

With Laura's permission, I'm sharing some of the photos here today.

The scene in the Namib Desert:




Note the black stripe on the crest of the hill in this shot:


It appears to be a dike of basalt/dolerite/mafic rock:



Boulders of the mafic rock go tumbling down a ravine:


The SEA Semester group's campsite:




Laura pulls a folded & boudinaged granite dike out of her hat:


Closer shot of the geology:






The rock cross-cut by the granite dike. Namibian dollar for scale; same size as American quarter:




Little tafoni hole:


Bigger tafoni holes:


Medium-sized collection of tafoni holes:


While I'm sharing other people's Namibia photos, go check out the collection from Greg Willis, a blog reader who attended the GSW spring field trip on Sunday.

Thanks, Laura, for the rocks and for the photos!

Labels: africa, geology, granite, namibia, nova

Whew!

Sorry I haven't posted much here in the past week. I've been swamped.

The good news is that my biggest task is now off my plate (just turned in the first draft of my MSSE capstone to my advisor), and that means I've got some spare attention left for the blog.

I thought I would take the opportunity to share some images from this past weekend's NAGT (National Association of Geoscience Teachers) Eastern Section conference, held at the NOVA Loudoun campus. On Saturday, I led a version of my "Bedrock Geology of Washington, DC" trip for a group of eight conference attendees.

All these photos are from Randy Newcomer, Director of Training and Services for Complete Safety Solutions of Lititz, Pennsylvania, and are posted with his permission... and my annotations!















If you're interested in seeing (most of) these rocks, join next Sunday's Walkingtown, DC tour!

Labels: conferences, dc, field trips, meetings, msse, nova, piedmont

One of my Honors students, Hope W. (author of yesterday's discussion of the Chalk Point Power Plant), kept a tally on Facebook of quips and phrases from this semester's Environmental Geology class. Now that the semester is over, I offer them to the public at large, despite the utter lack of context. Enjoy!


"Imagine how the lava feels."

"Earthlings are made of Earth."

"What do meteorologists study? Hint-- NOT meteors."

"It [the oceanic crust] is like a giant sheet of tissue paper."

[Referring to the continental crust, in comparison to the oceanic crust] "It's light and fluffy, like a souffle."

"We don't know the actual specifics."

"When you go up, you're not going North - you're going away from the Earth."

[Dramatizing the extraction of paleomagnetic data from rocks] "Continent, where was the pole for you 600 million years ago?"

"Oceanic crust is like James Dean and continental crust is like Dick Clark."

"Here's what we know about tectonic plates: some of them are big... some of them are itty-bitty."

"You can't forget Djibouti."

[Referring to the 1811-1812 New Madrid earthquakes] "There was just no one west of that to report how much shaking there was. Or at least no one who spoke English and felt like talking."

"Take my word for it man! I'm a scientist... No, that's not how it works."

"I have a nice layer of peanut butter on my arm."

"The same thing happens with rocks... it just takes longer."

"As continents move along they pick up junk."

"L.A. will end up in the armpit of Alaska."

[Referring to Redoubt] "Drama-queen of a volcano."

[Comparing geologic hazards] "If you use up all your water, then you die and you don't have to experience the earthquake."

"If bamboo collapses and falls on you it doesn't hurt anywhere near as much as brick."

Let me know in the comments if any of these requires an explanation...

Labels: analogies, humor, nova, teaching

Today, I present a guest post from my student Hope W., who described her experiences visiting the Chalk Point Generating Station in Maryland on our Environmental Geology field trip the weekend before last. The essay is posted here with her permission. Enjoy! -CB

The Chalk Point Generating Station is a coal burning power plant owned by the Mirant Corporation. Our guide during our tour was Greg Staggers, the plant manager. There were three main subject areas that Mr. Staggers talked to us about: power generation, the economic supply and demand, and environmental regulations and precautions.

Power Generation:
Mr. Staggers explained how the station has two different types of units. They have steam units and combustion units. Mr. Staggers described how the two different types of units are designed. He said that the steam units are like giant boilers, and that the combustion units are like jet engines. The plant has four steam units and seven combustion units, both types use fossil fuels to produce energy. Mr. Staggers explained how when power is first generated it is at too high of a voltage to be safely used by the public in homes or offices; and how the current has to be run through various lines to transformers and substations in order to be brought down from 20,000 volts (the level generated) to 110-220 volts (the level used in homes and offices.) Mr. Staggers pointed out the transformer field we drove past on the way in on the aerial photograph of the plant explaining that that’s where the process of conversion begins.

In response to Sophia's question about why the plant was built next to the water, Mr. Staggers explained the complex system for using water from the river to cool the equipment in the plant. As he talked in depth about this system he described how ideas improved through time and experience, as well as environmental regulations which lead the plant to finding more efficient and ecological ways of utilizing the river water. Later on when we took our tour through the plant we had the opportunity to see the some pipelines that the river water runs through. The water runs through the pipe-lines to cool the steam that is emitted during the power generation process. When the river water is released back into the river from the plant it has picked up no chemicals, and has only increased in temperature by approximately 20°F.

Mr. Staggers told us about four of the units that get run; units 1 and 2 which are combustion units and units 3 and 4 which are steam units. When running at full capacity units 1 and 2 operate at 90% efficiency, burn 2.5 million pounds of coal per hour, and use 14 megaWatts of the energy produced to operate; and when units 3 and 4 are running at full capacity the burn 650 gallons of oil per minute. Mr. Staggers informed us that the enormous pile of coal we saw on our way in would last for 45 days if the plant were running at full capacity.

Economic Supply and Demand:
In the 1990's the system was deregulated, which basically means that the power generation, wholesaling of the utility, and the supply distribution were all split up. So when the Chalk Point station produces energy they sell it to PJM a 'middleman' who will then sell it to the suppliers like Dominion Power etc. who then sell and distribute the supply to the public. I mentioned the transformer field earlier in this paper in reference to the generation process, but the transformer field has economic implications as well. The transformer field is also where the producers pass of the ownership of the energy to the middleman.

Mr. Staggers explained the bidding system for establishing the market value for each day. In the bidding system if you are over producing you get paid the difference in price from your morning bid in real time. During the tour we got to see the control rooms where the market price rates were being adjusted in real time. In response to Dustin's question about how they know when to produce Mr. Staggers explained how the middle men suppliers make that call based on the morning bids and the actual demand by the public, when the suppliers make the decision about production levels they call the plant to inform them of how much they need to be producing.

In terms of the national economy coal is the cheapest in explicit costs, in equivalent quantities the price for coal is 1/3 that of oil and natural gas prices, which is why more than 50% of the U.S.'s power is generated by coal. In terms of the local economy the Chalk Point station produces a 500 thousand volt ring around D.C. It is estimated that in the next five years 1 million homes will be added to the market that the Chalk Point station caters to.

The demand for coal is influenced by seasonal changes which gives it a cyclical demand. Callan asked if the increased attention on alternative methods of energy has affected the demand for coal in terms of reduction. Mr. Staggers said that no such change has been apparent and that the cyclical trend has followed a predictable pattern.

Environmental Regulations and Precautions:
Mr. Staggers told us about the regulations the plant has been mandated to conform to, as well as what the plant has done of their own accord for the sake of the environment. Some of the changes that the plant made in the past include setting up new stack facilities in 1982 because of environmental regulations. When the clean air act was passed in 1992 brought down their level of pollutants they were releasing into the atmosphere from 1.4 to .7 Further regulations such as; the separated overfire air controls in 2000, selective auto-catalystic reduction in 2007, and selective catalystic reduction in 2008 brought the pollutant rate down to .06. All of the methods above have dropped total output capacity by some amount.

The plant has also put up two boundary nets to protect fish from the areas where hot water is released and two more boundary nets as well as a fine mesh screen to prevent the fish from getting sucked up into the pumps for the cooling system. The plant has many systems in place to reclaim energy where they can to avoid waste, such as how they use residual heat from the coal burning process to heat the incoming air from its current temperature to be closer to the temperature required for being used as an infuser in the combustion process. The plant is in the process of building a "scrubber" which will reduce the sulfur emissions by 98%. The method this "scrubber" will use will allow the plant produce and collect gypsum which the plant will sell for its use in drywall. The plant also has a system set up to collect ash by a precipitation method; the ash collected is also sold for its use in drywall.

The plant has continuous emissions monitors which monitor emission levels of CO2, SO2, and NOx. The data from the monitors is sent quarterly to the State and the E.P.A. In the control room Callan asked a question about the plant's ppm output of CO2. Mr. Staggers said that measure by percentage and he did not know the output in ppm . This discussion lead to a very clear statement by Mr. Staggers that he wasn't convinced that it really made a difference. Mr. Staggers informed us that the plant's output of CO2 is 12% of flue gas volume, which Callan calculated to be 120,000 ppm. From Mr. Staggers' point of view as a producer of a commodity it is hard to see much else besides bottom line explicit costs. This was not his position out of greed, but out of responsibility to keep the company running so he has a job to provide for his family, and his employees as well. On the other hand, scientists cannot escape the implicit costs of CO2 emissions.

There needs to be a level headed discussion in a neutral setting were the two groups can learn to understand each other and start to cooperate. We as individuals and a nation must step up and set the example. When we start working together we will create the safe harbor necessary for understanding and cooperation to grow and flourish.

Labels: coal, energy, environmental, maryland, nova, oil, teaching

Here's the results of a neat little experiment my Environmental Geology students did a couple weeks ago. This is the first time I've run this activity, and I was pleased with the results:

Labels: climate change, CO2, global warming, nova, teaching

On May 1, Northern Virginia Community College (NOVA) will host a public hearing to receive comment on environmental sustainability opportunities within the Virginia Community College System (VCCS). Community members are invited to participate with faculty, staff and students at the hearing, scheduled for 9 a.m. in the theater at the Ernst Community Cultural Center on NOVA's Annandale Campus, 8333 Little River Turnpike in Annandale.

"For several years, NOVA has been taking steps to make its buildings and operations more environmentally friendly, more energy efficient and more sustainable," President Robert G. Templin Jr. said. "The Virginia Community College System has now made such efforts a major priority for the entire VCCS."

To fulfill this mission, VCCS Chancellor Glenn DuBois appointed a Task Force on Environmental Sustainability. In his charge to the task force, DuBois said, "The sheer size of the VCCS, with nearly 400,000 students being served in more than seven million square feet of space throughout 220 buildings, demands leadership on the issues of energy efficiency, environmental stewardship and curricula development."

The task force will develop environmental sustainability priorities related to construction, renovation and the operation of facilities. The members will also identify opportunities to work with community partners to support and promote environmental sustainability. In addition, the committee will recommend curricula enhancements and new workforce programs that respond to the growing 'green' economy. Contracting procedures will be evaluated with a goal of implementing procurement practices that promote the use of technologies, products and practices that are environmentally beneficial.

To learn more, contact Ray Bailey, chair of NOVA's Committee on Environmental Concerns, at 703-257-6683 or rbailey@nvcc.edu.

Labels: environmental, nova

Almost a week after the field trip to Old Rag Mountain, and the Facebook-hosted pictures keep trickling in. Here's some shots by NOVA student Eileen Lodovichetti, and an ensuing discussion of feeder dikes and supercontinent breakup.

Here's a shot of the upper reaches of Old Rag, showing the characteristic spheroidal weathering of the Old Rag Granite and the relative lack of trees on top:

photo by Eileen Lodovichetti

...And here's a shot that Eileen took which shows the interior of one of the weathered-out feeder dikes we had to hike through on our way to the summit. You can actually see the classic geoprofessorial arm-waving caught in blurry motion!

photo by Eileen Lodovichetti

This is one of the coolest things about hiking Old Rag: after scrambling up on top of spheroidally-weathered granite domes, you drop into these tabular "hallways." The astute observer will note that the floor is made of a fine-grained, dark-green-colored rock, quite distinct from the light-colored, coarse-grained granite that makes up most of the mountain. These are dikes of metamorphosed basalt that intruded the granite during the breakup of the supercontinent Rodinia in the Neoproterozoic era of geologic time.

Here's one of my former Field Studies in Geology students, Mike Nelson, pointing out a similar dike along Skyline Drive, in the main part of the park:


Basically, the story goes like this: Around 1.2 to 1.0 Ga, continental fragments amalgamated into a supercontinent called Rodinia. In Virginia, this is recorded in the rocks of the Blue Ridge province, where the basement consists of granitoids (granites and related rocks) and metamorphosed granitoids (gneisses, mylonites). Among the youngest of these is the Old Rag Granite, which intruded the Pedlar Formation granite gness around 1.0 Ga.

Later, Rodinia broke apart, resulting in an extensional tectonic regime and mafic volcanism. Fractures opened up in the Old Rag Granite and funneled mafic magma towards the surface. Massive eruptions of basalt blanketed the landscape. The resulting layers of basaltic lava are known as the Catoctin Formation. At Old Rag Mountain, we can see some of the plumbing that led to these flood basalt eruptions: these are feeder dikes, because they "fed" the eruption above them.

Because the dikes (which were metamorphosed to greenstone during ~300 Ma Appalachian mountain-building) weather more rapidly than the Old Rag Granite, they are typically recessed into the landscape. That's what makes the "hallways" in the photograph above. Here's two more images, showing these weathered-out feeder dikes:



Check out how there's moderately-developed columnar jointing extending across the dike. These columns form perpendicular to the cooling front, and the dikes would have lost their heat out the sides. In horizontal lava flows, the heat is lost from the top and bottom surfaces, so you get vertical columns. Here, a vertical dike produces horizontally-oriented columns. Hikers appreciate these "steps" as they squeeze through the dikes on their way up the mountain.

Here's a map of part of Shenandoah National Park:


Please ignore the "hover" instructions at the lower right. I've reproduced the "hoverable" image below. Key: the orange is the Pedlar Formation. The pink is the Old Rag Granite, and the green is the Catoctin Formation. Feeder dikes of the Catoctin are shown as green lines.

Now, let's take away the map, and just preserve the orientation of the feeder dikes. This will tell us the overall tectonic stretching direction:
Various plate reconstructions show either Amazonia or the Congo craton offboard of Virginia at the time Rodinia broke apart and the Iapetus Ocean began seafloor spreading. I've illustrated it here as the Congo, but that might be wrong.

So: the hike up Old Rag is great exercise, and offers scenic views, but for those willing to consider the rocks and how they got there, it's an insightful view into the tectonic past.

Lastly, here's a lovely, well-developed weathering rind on the Catoctin meta-basalt (greenstone). When the dark green rock adjusts to the conditions at the Earth's surface, it breaks down, resulting in the tan/"buff" color on the outside. You're watching the rock "rot" from the outside surface, working its way inward:


More on the geology of Shenandoah National Park can be seen at this page on my website.

Labels: appalachians, basalt, blue ridge, field trips, metamorphism, mountains, national parks, nova, plate tectonics, shenandoah, structure, weathering

Last weekend, I took a group of students, mostly from NOVA but also 3 from GMU, up to hike Old Rag Mountain in Shenandoah National Park.

Here's a Google Map showing the terrain (and trails, which is a cool new addition to the already cool Google Maps):


The crew discusses debris flow deposits in the forest on the way up the mountain:

photograph by Charlie Corrick

The first spot where we get a nice view out over the valleys below:

photograph by Charlie Corrick

Spheroidal weathering in Catoctin Formation greenstone:

photograph by Jared Fortner

Spheroidal weathering in granite (the Old Rag Granite, 1.0 Ga):

photograph by Charlie Corrick


photograph by Charlie Corrick

Student Jared atop a spheroidally-weathered boulder of the Old Rag Granite:

photograph by me

Grain-size differences in the Old Rag Granite (balanced atop my leg):

photograph by me

Non-foliated Old Rag Granite (showing lovely "blue quartz"):

photograph by me

And the foliated version of the Old Rag Granite:

photograph by me

Labels: appalachians, basalt, blue ridge, field trips, geology, granite, igneous, mountains, national parks, nova, structure, weathering

This fall, Professor of English Joyce Brotton and I will be offering a new linked pair of Honors courses: Her English 244, Survey of English Literature II, will be paired with my Geology 106, Historical Geology. Enrollment is for Honors students or by permission of the instructors only. Both classes will meet in CS 219 on Mondays and Wednesdays. Dr. Brotton will teach from 11:30am-12:45pm, then we'll have a lunch break for 45 minutes. At 1:30pm, I'll pick up with lecture until 2:45pm, and on Wednesdays, we will follow that with lab.

Dr. Brotton and I have collaborated in planning the curriculum, which in the literature half of the class will include readings of Darwin, Lyell, and "A Pair of Blue Eyes" by Thomas Hardy (which features trilobite eyes!). Joyce plans to conclude the literature class with The French Lieutenant's Woman, which attempts to reconcile man's place in a world that science is revealing more and more to be indifferent to man. On the geology end of things, writing the field trip reports will hopefully more of a satisfying practice with an English professor on hand to advise!

Interested NOVA students should contact Dr. Brotton or me for more details.

Labels: nova, teaching

Here's some photos from today's Physical Geology class field trip to the Billy Goat Trail. It actually snowed on us a little bit... cold! My student Luke O'Neil took all of these, hosted on his Facebook page, and this is an experiment to see if I can post Facebook photos on my blog... keeping my fingers crossed...

Migmatite:


Il profesore showing tilted tree trunks (knocked in a downstream direction during floods):


Folded graded bed in metagreywacke:


Students circle around an exotic boulder of the Catoctin Formation greenstone (from the Blue Ridge province); the boulder was transported downstream by the ancestral Potomac River when it was flowing on the Bear Island strath, before incision and abandonment of the former river bottom to become a bedrock terrace:

Labels: field trips, geology, maryland, national parks, nova, piedmont, rivers, teaching

NOVA Assistant Professor of Geology (Loudoun Campus) Will Straight will have his paper, "Bone Lesions in Hadrosaurs: Guided Computed Tomography for Paleohistologic and Stable-Isotopic Analysis," published as the featured article in the June 2009 issue of the Journal of Vertebrate Paleontology.

Way to go, Will!

Labels: dinosaurs, fossils, isotopes, nova

It's my pleasure to inform you that my colleague Ken Rasmussen won this year's John Moss Award for the teaching of geology, as bestowed by the Eastern Section of the National Association of Geoscience Teachers. I nominated Ken, and was supported by nearly a dozen supporting letters from his legions of current and former students, many of whom credit him with launching them on a career in geology. Congratulations, Ken! (and keep it up!)

Labels: nova, teaching

Last week, I updated my field trip photo page with a fresh batch of images from last spring's Field Studies in Geology course to the Billy Goat Trail. Here are the new shots:












All photos are by Kevin Mattingly, NOVA photographer.

Labels: field trips, maryland, nova, piedmont, teaching

Yesterday, four Honors students and I went out to West Virginia's route 55 (between Wardensville and Moorefield), to look at some sedimentary strata and associated tectonic structures. Our guide was my friend David Dantzler, an enthusiastic amateur geologist. Here's a map of the terrain we traversed:



As you can see, this is part of the Valley & Ridge province, an area of the country defined by Paleozoic rocks that were folded and thrust-faulted during the Alleghenian phase of Appalachian mountain-building. Recently, a new road has been constructed traversing these valleys and ridges. It's a bit of a boondoggle, a pet project of West Virginia senator Robert Byrd which funneled federal dollars into the Mountain State, ostensibly to make it easier for the chicken farmers of Moorefield to get their birdie bits to market on the east coast.

This image ought to give you a sense of the project's scale (big bridge), and how much use it gets (no one on the bridge):


But the U.S. taxpayer's loss is the geologist's gain... There are some pretty spectacular new exposures of Valley & Ridge rocks along the new route 55. Here's the NOVA van parked at an outcrop of Tuscarora Sandstone that is arched up into a broad anticline. Again, notice how few people are driving on route 55 here:


Ooh, look: heavy traffic!


Contact between the lower Tuscarora Sandstone (a Silurian-aged extremely pure quartz sandstone, variably fused to quartzite), and the overlying (darker-colored) formation, which is either the Rose Hill Formation or the Mackenzie Formation at this location:


We found oodles of cool trace fossils:







But it wasn't just sedimentary layers. There were also some cool tectonic structures, like this joint in the Tuscarora, showing a beautifully developed hackle fringe:



Here's some "pencil cleavage" where fine-grained shale develops cleavage that intersects the planes of fissility, causing it to fracture in long slivers:



I slammed on the brakes for this one: an awesome anticline...


I forced David and the students to act out the orientation of the bedding planes at this anticline:


Honors student Jason points out a small thrust fault in the outcrop above him: You can see the offset in a greenish/gray shale layer:


In case it wasn't obvious above, here's a zoomed-in shot, with the offset layer highlighted (the miracles of Photoshop!) and the fault labeled:


We all had a grand day outside, and the rain held off until our return trip, which was pretty great. Thanks to David for showing us these rocks, and thanks to my students for being smart and inquisitive and into field trips.

Labels: appalachians, devonian, field trips, fossils, mountains, nova, politics, primary structures, sediment, silurian, structure, teaching, valley and ridge, west virginia

It's getting to be springtime... and that means field trips!

My first field trip of the semester is tomorrow: my friend David Dantzler has organized a trip to look at stratigraphy and structure out on a new highway in West Virginia. I'm supplying half a dozen Honors students and a NOVA minivan, but David's handling the content. And of course, I'll be on hand to comment on "teachable moments." Looking forward to it.

Other trips upcoming this semester: Billy Goat Trail (x4!), Massanutten Mountain, Old Rag Mountain, Washington DC walking tour, and a weekend-long structural geology trip to the Blue Ridge and Valley & Ridge provinces. I love field trips; really they were the aspect of majoring in geology that appealed to me the most - the fascination with Earth processes took longer to develop.

See you in the field!

Labels: blue ridge, field trips, maryland, nova, piedmont, teaching, valley and ridge, virginia, west virginia

From NASA's Earth Observatory:

Labels: nova, snow

Sam Love, one of the original national staff members of the first Earth Day, will speak on April 22 on the impact of changing our environmental culture. The event will be at 12:30 p.m. in the CE Forum on the Annandale Campus. Free & open to the public.

In his Earth Day 2009 presentation, Love will review some of the early fantasies based on cheap abundant energy. He then lays out some operating rules for a sustainable future and why there is reason for hope.

More information on p. 11 of last week's Intercom.

Labels: environmental, meetings, nova

In Environmental Geology lab last week, we were playing with dirt... and sand... and gravel... and other granular materials, piling them up to see the angle of repose.

One of my students, Kristen P., brought in little "Monopoly" houses so that her experiments carried a bit more significance...




I thought this was very clever -- it made you "care" more about the angle of repose when someone's "home" was at stake... Good work Kristen!

Labels: humor, mass wasting, nova, teaching

Even if you don't have iTunes, the NOVA-Annandale Science Seminar series will be televised...

Check at our new webpage: http://www.nvcc.edu/annandale/scienceseminar/

Specific video: Dick Pellerin on math's many uses; Me on my western roadtrip.

Labels: geology, meetings, nova, science and society, travel

Enjoy!

Labels: meetings, nova, tech

Just got a batch of images from the NOVA photographer, Kevin Mattingly. I particularly like this image of last spring's Field Studies class at the Billy Goat Trail:

Here, we're overlooking the upstream end of Mather Gorge, checking out some ~360 Ma lamprophyre dikes exposed there -- but offset on either side of the river!

Labels: devonian, field trips, national parks, nova, piedmont, teaching

Science Seminar: The Tropical Reefs of Roatan

Friday February 20, 2009
CE Forum 12:00 noon - 1:00 pm

Jill Caporale, NOVA Faculty
Dianne Heath & Robert Schreiner, NOVA Students

Join Professor Jill Caporale and her students Dianne Heath and Robert Schreiner as they discuss the reefs, dolphins and mangroves of Roatan, Honduras. Jill Caporale believes that getting students out in the field is the best way to for students to learn and rekindle their "natural sense of wonder."

Jill Caporale has taught Biology and Natural Science at Northern Virginia Community College as an adjunct and full-time faculty since 1988. She has taken students to the rainforests of Costa Rica and the Reefs of Honduras. This year she will be returning with students to investigate the tropical waters off the coast of Roatan, Honduras. So, if you have ever wanted to snorkel coral reefs and swim with dolphins come listen to their talk, or better yet, sign up to go this summer.

Sponsored by the Lyceum and the Math, Science Engineering Division

Labels: meetings, nova, reefs

For those of you who missed it, here's video of Mike Tidwell's talk at NOVA last Thursday.

Labels: action, climate change, global warming, maryland, nova, podcasts and vodcasts, politics, virginia

Because he's coming to campus tomorrow (Thursday), last weekend I watched Mike Tidwell's movie We are all Smith Islanders. It's a 35-minute long documentary about how climate change is effecting the states of Maryland and Virginia, and the District of Columbia. Though it is a political document (and not a scientific documentary), I think it's a worthwhile enterprise because it connects the global to the local. We hear a lot about climate change, but when someone actually walks through Ocean City, Maryland, pointing out what three feet of sea level rise would look like, it fosters a connection based on shared landmarks.

Thanks to archive.org, you can actually watch the movie in low resolution on the Internet. Google video also keeps a copy available.

Or, if you'd prefer it in higher resolution (on DVD), you can find it at the NOVA library.

Labels: action, climate change, dc, global warming, maryland, movies, nova, politics, virginia

As promised, here's some details for the event I mentioned the other day:

2:15- 4:45 Lisa Williams: Various displays of models, samples, artifacts, posters.
2:15 - 2:25 Bill Stanclift: Piano
2:25 -2:30 Reva Savkar : welcome and introduction of first speaker
2:30 - 2:45 Ralph Eckerlin: "Review of Darwin's life and accomplishments"
2:50- 3:10 Tom Macke: "Lincoln"
3:15 - 3:30 Karla Henthorn: "Common Misconceptions About Darwin"
3:35- 3:50 Jill Caporale: "The poetry in Darwin"
3:55 - 4:05 Nan Peck: "fun Lincoln-Darwin game"
4:10- 4:25 Bill Gorham: "Thomas Henry Huxley: Bulldog"
4:30 - 4:45 Callan Bentley: "Charles Darwin, Geologist"

200th Birth Anniversary of Lincoln and Darwin Celebration: The event will be held in the Ernst Community Cultural Center Forum on the Annandale campus of NOVA, Feb 12, 2009, starting at 2:15pm.

Labels: evolution, history, meetings, nova

My clever & creative colleague Reva Savkar (chemistry) is putting together a celebration of the 200th birthday of two important individuals in the history of the world: Abraham Lincoln and Charles Darwin, both born on February 12, 1809. The event will be held in the Ernst Community Cultural Center Forum on the Annandale campus, starting at 2:15pm.

The details are still being organized, but the event will feature short talks, music, and activities both from NOVA faculty and outside guests. Confirmed so far are: Bill Stanclift, Reva Savkar, Ralph Eckerlin, Tom Macke, Karla Henthorn, Jill Caporale, Nan Peck, and Bill Gorham.

I'll be presenting a 15-minute talk, starting at 4:30pm entitled "Charles Darwin, Geologist."

The event is free & open to the public. Join us!

Labels: evolution, geology, history, meetings, nova

Yesterday was our first big snowfall (well, "big" by DC standards) of the year. We got around 3 inches total, but then last night that got covered and compacted by a layer of freezing rain. Here's the scene yesterday morning around 8am from my apartment, looking west over Beach Drive, Rock Creek Park, and the National Zoo (movie is 30 seconds long):



The College was open, though, so in we all trooped. Here's the campus as viewed from Little River Turnpike:



And a few shots of the snow-laden campus...




The snow continued into the afternoon, with predictions of freezing rain for the evening. I had my Physical Geology class, but then the word came down from on high* that NOVA would be closing at 2pm. So, no lab, and no Environmental Geology. We all trooped home to our various classes.

* NOVA has put together an impressive new emergency alert system. It automatically sends e-mails, sends text messages to our cell phones, and (as I found out yesterday in the middle of my Physical Geology lecture) causes a window to open up on all campus computers saying "ALERT: The College will be closing today at 2pm due to snow." I was in the middle of a PowerPoint slide showing why weak bonding in mineral crystal lattices cause cleavage, and BAM suddenly there was a flashing alert up on the screen. Instantaneous notification for the entire class. Another one was open on my computer when I got back to my office. Pretty effective, I think.

Labels: dc, nova, snow

It was announced today that Dr. Jill Biden, the wife of Vice President Joseph Biden, is teaching as an adjunct professor of English for two classes this spring semester at NOVA's Alexandria Campus. Dr. Biden has a 28-year career as an educator, having held a 15-year appointment as a professor of English at the Stanton/Wilmington campus of Delaware Technical and Community College where she taught composition and developmental English. She holds a Master's degree in English from Villanova University and a Master's degree in reading from West Chester University. She earned a doctorate in education from the University of Delaware in 2007.

Welcome, Dr. Biden!

Labels: news, nova, politics

I'm very pleased to announce that my colleague Ralph Eckerlin, professor of biology at NOVA-Annandale, has been selected as a recipient of the 2009 Virginia Outstanding Faculty Award. The award is the highest honor for faculty bestowed by the Commonwealth.

From the letter the President of Northern Virginia Community College, Bob Templin, just sent out to all the faculty and staff:

Dr. Eckerlin has served with distinction at NOVA since 1971. He has always given primary attention to effective teaching while also maintaining a strong record of research in his specialization of parasitology and making numerous other contributions to his profession. A previous recipient of college awards as the Student Government Association Most Outstanding Faculty and the Alumni Federation Outstanding Faculty Member, Dr. Eckerlin is praised by students and colleagues as an exceptionally dedicated and inspiring teacher. He takes particular pride in serving as advisor to students seeking admission to professional fields in biology and medicine, and in chairing or serving on committees to bring new faculty to the college who will continue the strong institutional tradition of excellence in the instructional program for biology and other sciences. He has sponsored student trips and conducted research in such locations as Puerto Rico, Jamaica, the Bahamas, Mexico, Belize, and Costa Rica. Closer to home, he organizes regular trips to expose students to the wonderfully diverse biota of Virginia, whether in Highland County or the Dismal Swamp.

Beyond NOVA, Dr. Eckerlin has been very active in a number of professional societies, to include serving as president of the Tropical Medical Association of Washington, the Helminthological Society of Washington, and the Virginia Association for Biological Education. He also served as editor of the journal Comparative Parasitology as well as being a member of its editorial board since 1984. His numerous papers in peer-reviewed journals have dealt with a diversity of subjects, including mammals, reptiles, beetles, fleas, lice, nematodes, and protozoans.

Dr. Eckerlin is the seventh NOVA faculty member to receive this prestigious award. This is also the fourth year in a row that a NOVA faculty member has been a recipient. [...and the second year in a row just within the Math, Science, and Engineering division at Annandale -- last year, it was Walerian Majewski in physics!] He and eleven other faculty from Virginia colleges and universities will be recognized at special events in the General Assembly and elsewhere in Richmond on February 19.

Please join me in congratulating our colleague Ralph Eckerlin as one of NOVA's and Virginia's very best!

Bob

Congratulations, Ralph!

Labels: arthropods, mammals, nova

Due to a scheduling mishap, this semester I'll be teaching my Environmental Geology lab in the new Science Learning Center in the Schuler Building on NOVA's Annandale campus.

This past Thursday night was our first session in there. Exploring the new facility, I opened up an old-looking refrigerator back in one corner. "What's in here?" I wondered....



Whoa! A bunch of dead birds! These are, no doubt roadkill (or window-kill) samples that are awaiting preparation as 'study skins.' Under professor Walt Bulmer, NOVA has developed a robust collection of study skins to aid in ornithological studies. (I'll have to shoot some photos of those sometime.)

Though I hadn't expected to see a pile of dead birds in the fridge, I soon recovered from the shock. Before converting to geology, I used to study ornithology, and have spent time prepping study skins in the lab at William & Mary (and once, in my dad's basement, with a Sturnus vulgaris that turned out kind of stinky). Returning to my students working on their lab, passing the anatomical models and the physics references, I thought how refreshing it was to be working in a lab utilized by all the sciences.

I guess in retrospect, I should have suspected the fridge's contents when I saw this cartoon taped to the front of the fridge door:

Labels: birdies, humor, nova, teaching

Labels: art, blogs, humor, nova

Here's a copy of my presentation last week at the NOVA "Power Up Your Pedagogy" conference, hosted here at the Annandale campus (sponsored by our Center for Excellence in Teaching and Learning). Apparently there were some technical snafus for one (both?) of the scheduled playings of the talk, so I wanted to put it online for anyone who missed it. It's 13:40 in length, available as an .avi file. You'll have to download it to your computer, because I can't figure out how to embed it here.

Other talks from the conference are listed (some with video) on the PUP page on the CETL website.

Labels: blogs, conferences, geology, nova, teaching, tech

Following the success of last year's Climate Change Symposium, this year NOVA will host Mike Tidwell, the dynamic director of the Chesapeake Climate Action Network, for a talk on global warming and what college campuses can do about it. Mr. Tidwell has a reputation as a terrific speaker, so I'm really looking forward to his talk.

He will be speaking at 11am on Thursday, February 5, in the Ernst Community Cultural Center Theater (CE building) on the Annandale campus of Northern Virginia Community College. The event is free and open to the public. I encourage you to attend if you're in town. A booksigning will follow in the Theater lobby.

Labels: climate change, global warming, maryland, meetings, nova

Howdy, howdy. It's the first day of winter, the shortest day of the year. It is also the one-year "blogiversary" of your humble NOVA Geoblog. Our first day on the job, we put up three separate posts of the "short and sweet" variety. Since that time, we've put up posts at an average rate of 1.24 per day (454 posts over 365 days). ("We've" also started referring to "ourselves" in the third-person plural, a disturbing development indeed.)

Some of these posts I feel pretty proud of, in terms of the detail they express, the big ideas they examine, or the language I used to write them. Others have just been meeting announcements, job opportunities, or brief mentions of newsworthy items hosted at other sources. Here's a list of 15 of my favorites:

• Geology along Windy Run, Virginia I
• Geology along Windy Run, Virginia II
• Ultramafics in the Piedmont
• Migmatitic
• Virtual Billy Goat Trail trip
• Another field trip transcript
• Shenandoah NP: Corbin Cabin area
• Western conglomerates, Culpeper Basin
• Massanutten Synclinorium field trip
• Perspectives on coastal tectonics
• Horseshoe crabs of Delaware Bay
• My favorite analogies
• Mineral habit and Japanese watermelon
• Rock varieties of Hawai'i
• Atop Mauna Kea

I think there are some trends here: field trip experiences and analogies are my favorites.

It's been a good year. Since I started this blog, I've travelled to Northern Ireland, Buffalo and Niagara Falls in New York, Montana, Kentucky, Wyoming, the Grand Canyon, Kansas, Colorado, Utah, Hawai'i, and as of next week I'm off to Ecuador and (knock on wood) the Galapagos. In that year, I've taught hundreds of students in courses ranging from one-credit field studies to four-credit Honors courses. I also took 14 credits of graduate coursework from Montana State, via the computer and in the field in the northern Rockies. At NOVA, I've gotten involved in some good activities, from greening the College to leading caving trips. I've published some articles and some cartoons, and been contracted to do art ranging from squirrel woodcuts to diagrams of coastal processes in the Gulf states. I got promoted; I got some grants; I expanded and maintained my network of geological contacts throughout the mid-Atlantic region and across cyberspace. I volunteered leading geology walks along the Billy Goat Trail and through Washington, DC, and served in various official roles for the Geological Society of Washington.

...All told, it's been a full year.

The blog has been successful. I've been delighted to get so much positive feedback from readers, and glad that the blog could serve as a case study in articles in Geotimes and EARTH. I'm also grateful for the corrections when I screw something up: I appreciate the critique and feedback. The counter I added in mid-spring (I forget exactly when) has tracked almost 50,000 hits. I put Sitemeter on in mid-August, and it's tallied up ~28,000 visits in those four months, with ~42,000 page views. That is kind of a lot, I think.

I'm very pleased to see that I have not been alone in this endeavor. The geoblogosphere has exploded in diversity and population over this same time, and I'm pleased to have been able to document that with the "Rise of the Geoblogosphere" talk at the Geological Society of Washington (and ensuing post) in September. Thanks very much to everyone who participated in the survey.

My hats off to Maria, Ron, and Andrew for paving the way for the rest of us, and to Chuck, Kim, Brian, and Chris for providing such compelling examples to emulate. I've been delighted to explore the world of blogging in a cadre of 'yearlings' that includes luminaries like Dave, Garry, Bryan, ReBecca, Ralph, Jessica, Silver Fox, Dave, Lee, and Julian, among so many others that I wouldn't be able to list them all. (I leave that to Lutz.) I am delighted to see relative newcomers like Ed, Chris, Chuck, Jesse, Michael, David, and (my former/future student) Jay on the scene; I also hope for the new year to bring the resurrection of some old favorites, like Mel, Chris, Jeannette, and Jim. My sincere apologies if I've left your worthy blog off this incomplete list.

Happy solstice, everyone! Here's to another year of discussion and sharing!

Labels: blogs, nova

Christie asks: What are your top ten geological resolutions for the new year?


For me, the list would include:

1. visiting the Galapagos Islands
2. visiting the high Andes (Cotopaxi, Chimborazo), Ecuador
3. finding a cool outcrop of graded beds in the Martinsburg Formation (late Ordovician turbidites in the Shenandoah Valley of Virginia) that Rick Diecchio told me about last week
4. "walking on the Moho" in Gros Morne National Park, Newfoundland (late summer)
5. seeing Snowball rocks and Ediacarans on the Avalon Peninsula, Newfoundland (late summer)
6. visiting Egg Mountain paleontological site, Montana
7. joining my colleague Ken Rasmussen's field trip to the Culpeper Basin, a Triassic rift valley in northern Virginia
8. some cool trip next winter break (2009-10): perhaps Patagonia? Or Antarctica?

I've also got some big teaching resolutions:

1. Running a successful and robust Structural Geology course for George Mason University (spring semester).
2. Running a successful and innovation Environmental Geology course for NOVA (spring semester).
3. Running a successful and safe Regional Field Geology of the Northern Rocky Mountains course for NOVA (summer semester).
4. Preparing and running a successful and groundbreaking Honors Historical Geology course linked with English Literature 242 at NOVA, where the English professor and I will bridge the two subjects with readings of Lyell, Darwin, "A Pair of Blue Eyes," and others (fall semester).

On other topics:

1. Finish my M.S.S.E. degree (July)
2. Buy a house
3. Put together a series of geology 'vodcasts' on local geology
4. Write a few freelance articles
5. Publish one cartoon per month in EARTH
6. Prepping (cutting and polishing) a backlog of rock samples from all over the place
7. Successfully moving the geology department into our new building

Labels: canada, ecuador, geology, msse, newfoundland, nova, south america, teaching, travel, valley and ridge, virginia

This just in from the office of Virginia's governor, Tim Kaine:

"In higher education, our October actions reduced schools' 2009 base budgets by 5 to 7%. For 2010, I have increased the reductions to 15% for all schools, except the community colleges and Richard Bland, which will have the reduction level increased to 10%."

Especially in light of what I posted earlier today, this does not bode well.

Full text of the governor's remarks here.

Labels: economics, news, nova, politics, virginia

The current issue of Newsweek features an article that quotes NOVA President Bob Templin on how more students are signing up for classes at community colleges like NOVA, just at the same time the state is cutting our funding.

Labels: news, nova, politics, teaching

It's that time of the semester, when the field trips are over, and the field trip essays start rolling in. These papers I assign are intended to be syntheses of the field trips I take my students on. I want them to interpret the landscape as a geologist would, and support each claim about geologic events in the past with supporting evidence observed or discussed on the trip.

I offer my students the opportunity to submit a rough draft of their field trip paper, and then I give them feedback about both content and formatting/writing style, so they have a chance to revise before submitting a final draft. Each semester, about a quarter of the students avail themselves of this opportunity for feedback before the "real" paper is due. Giving them quality feedback is a time-consuming process, but I feel it's important both to cement geologic concepts in their minds, and to guide them in developing their writing skills.

Accordingly, it's been a slow week for posting on this blog. I've been too busy with work. However, this morning it occurred to me that I could capitalize on my grading efforts by sharing a student essay with you all, edits and all. Why do I think you'll be interested in such a thing? (A) I think it gives some insight into the practice of teaching geology at the introductory college level, and (B) I think this is an excellent rough draft for an essay about Washington, DC's geologic history. The student's name, of course, has been redacted:

Labels: cretaceous, dc, geology, nova, ordovician, teaching

Last week was field trip week for me. I led trips to the Billy Goat Trail on Tuesday and Thursday, and to Washington, DC, on Saturday.

On the Physical Geology field trip to the Billy Goat Trail, we saw rocks like amphibolite, metagraywacke, and migmatite:







Hope and Ana checking out the migmatite:


The group poses with the migmatite, to show how close anatexis is to their hearts...


Jane examines lamprophyre in a weathered-out dike:


Noting the characteristics of metagraywacke:




Traversing 'Pothole Alley'... Joel looks chilly...


Our lunch spot... Alex pretends to dive into the Potomac River...


Traversing 'The Traverse':


On the Historical Geology field trip to DC on Saturday, we were amused to find a jack-o-lantern that had facial hair resembling mine...



But that's not all! We also saw some geology. While you can get a more complete picture at my "DC Rocks" webpage, I'll post a few new photos of new outcrops here...

Here's a nice slab of granite (very angular) set in metagraywacke matrix (metamorphosed accretionary wedge complex)...


Here's two members of the Georgetown Intrusive Suite, showing the (earlier) gabbro stoping xenoliths into the (later) granite:


I love field trips. I love seeing my students light up at being outside, at getting a handle on the stuff we talk about all semester in class. I think field trips are super duper important.

Labels: dc, field trips, granite, igneous, maryland, metamorphism, nova, piedmont, teaching, xenoliths

Yesterday, I pulled up the Venetian blinds in my office window at NOVA, and this is what I saw:


Naturally, I had to take a photograph. It's puuurty.

While I had the camera out, I figured I'd shoot a few photos of the rest of my office, since it's full of all sorts of interesting clutter. Rather than explaining what all the doodads are in these photos, I figured it would be more fun to just post them and see if you can identify them all:















Have fun!

Labels: fossils, igneous, maps, metamorphism, minerals, nova, plants, sediment

Starting this month and going into January, Arlington County, Virginia is hosting a series of free workshops designed to help citizens make more environmentally-sustainable choices in their homes and workplaces.


For more information, click here.

Labels: environmental, meetings, nova, virginia

We've got a couple of part-time positions opening up in my division here on campus...

Lab Assistant
Trainer & Instructor I, Math, Science & Engineering (Position BIU)

Starting salary rate $15.60/hour, no benefits. Up to 30 hours per week.

Assist in laboratory setups for biology, natural science, and
chemistry. Clean and organize labs. Store equipment, models and supplies as
directed. Perform other tasks as directed. Required: A.S. in chemistry or
biology. Desired: B.S. in biology or chemistry. Previous experience in lab setup
for college labs. Open until filled.

Science Learning Center Coordinator
Trainer Instructor I, Math, Science & Engineering (Position BIV)

Starting salary rate $25/hour, no benefits. Hours as needed, up to 25 hours
per week.

Assist in setting up and coordinating the Science Learning
Center. Provide help with student review, tutoring, and advising outside of
regularly scheduled class and labs. Organize study sessions and open study
hours. Gather needed equipment and supplies; properly store and inventory
these materials. Required: Bachelor's in science or related field required.
Master's degree in science preferred. Desired: experience teaching college
science courses; ability to work well with students, faculty and staff. Open
until filled.

If you're interested in more details, e-mail Mary Vander Maten at mvandermate@nvcc.edu. To be considered for any position, a Virginia State Employment Application must be received in the Human Resources office by 5:00 p.m. on the position closing date. Employment with NOVA is contingent upon the successful completion of a required background check. A Virginia State Employment Application is required to apply for all positions. You may download a Virginia Employment Application from this link (use MS Word 2003; you can then type on the form, and then submit it via preferred method of e-mail attachment).

Labels: nova

Several years ago, (former) NOVA student Theresa R. put together a nice little webpage with rock and mineral photos. My favorite part is a "gray rock quiz" at the end. Check it out and see how well you do!

Labels: igneous, metamorphism, minerals, nova, sediment, websites

As has been mentioned elsewhere, Virginia governor Tim Kaine made some big budget cuts last week. The Commonwealth of Virginia has a rule that they must have a balanced budget every year. So with the economy in such shabby shape and Virginia's income predicted to have significant shortfalls, Governor Kaine has decided to trim the Commonwealth's budget. The official revenue projections forecast a shortfall of $973.6 million for fiscal year 2009 and $1.54 billion for fiscal year 2010, or just over $2.5 billion for both years. According to a press release from Richmond, "Governor Kaine will balance the FY 2009 budget through state agency savings and spending reductions of over $348 million and additional steps, including a withdrawal of about $400 million from the Revenue Stabilization Fund."

Two entities in the state government that are getting hit particularly hard by the proposed changes are (1) the Division of Geology and Mineral Resources and (2) higher education.

(1) As I mentioned earlier in the week, this was an issue of much discussion at the Virginia Geological Field Conference last weekend. I would like to share here an excerpt from an e-mail I got after the conference from Chuck Bailey (W&M), the president of the VGFC:

Unfortunately, with Virginia's looming budget crisis, the State is planning to severely cut if not eliminate the Division of Geology and Mineral Resources (DGMR). Here are some of the planned cuts:

• 9 (out of a staff of 21) will be laid off
• 1 staff member will be transferred to the Division of Oil and Gas
• 4 staff members will be reassigned to support the Abandoned Mine Land project
• DGMR will be left with a staff of 4 on state-funded positions (of which 3 are currently supervisory) and will not, in any substantive way, be able to serve the Commonwealth. Details of the plan are on pages 14-15 of the Governor's budget reduction plan.

We have an obligation to fight these cuts with vigor. DGMR has served the Commonwealth well and needs to be maintained, even through the lean times. For
me it is clear that these cuts are a deliberate action to eliminate DGMR; consider the fact that within the Department of Mines, Minerals & Energy, of which DGMR is one of six divisions, the only layoffs are being incurred by DGMR.

Not only are these cuts are extremely shortsighted, but inherently unfair.
What can be done about this?

The most important decision maker who is likely to consider input from DGMR customers is the Secretary of Commerce and Trade. He needs to know how people use DGMR products/services, especially if they use them to make money or protect people and property, and why DGMR is important to the Commonwealth. Company letterhead is preferable. He is:

Patrick O. Gottschalk
Secretary of Commerce and Trade
P.O. Box 1475
Richmond, VA 23218

The Acting Director of the Department of Mines, Minerals and Energy (which includes the DGMR) is:

Benny R. Wampler, Acting Director
Department of Mines, Minerals and Energy
P.O. Drawer 900
Big Stone Gap, VA 24219

A letter to the Governor can't hurt either:

Governor Timothy Kaine
Patrick Henry Building, 3rd Floor
1111 East Broad Street
Richmond, VA 23219

People should contact their own Delegates and Senators.

A Virginia Geological Field Conference Yahoo! listserv has been set up to facilitate discussion for those who wish (search "thevgfc"). [Note: I would encourage you to read this discussion, as it points out that the total savings are pretty meager (~$10,000 for the upcoming fiscal year, because of severance pay and what-not) considering the crippling cut in services. -CB]

We need to act quickly and with forceful clarity on this matter.

Thanks,
Chuck Bailey
President, Virginia Geological Field Conference

Please take the time to write a letter to one or more of these officials to let them know what you think of the proposed cuts. Also, I'd like to give a shout-out to Lee Allison, state geologist of Arizona, who posted on this issue earlier today.

(2) The second major area where budget cuts are hurting this blogger is in the 5% cuts to higher education in the Commonwealth. Though I utilize the maps and studies produced by the DGMR, their budget cuts don't effect my paycheck. But when the Virginia Community College System has to slash its budgets by 5%, that does change my bank account balance. NOVA faculty and staff got an e-mail from our president last Thursday (10/9), informing us that though the College would continue to provide its services essentially uninterrupted with a 5% cut, faculty salary increases, scheduled for November, would be "delayed until July of next year." This is a real bummer, though for me personally the bright side of it is that I got my promotion before all this went down, so at least I secured that pay raise before things went sour. Just the same, I'm going to miss the extra cash that was 'promised' on the contract I signed at the beginning of the academic year. With everything getting more expensive, it's a tough on faculty when their salaries don't keep up with inflation.

So it's looking kind of grim in the Commonwealth, folks. While I don't think a letter-writing campaign will effect the higher education cuts much, the DGMR is a small entity that has gotten hit disproportionately hard. If you can write a letter to help save the DGMR, please do. It's an important state agency that does great work. Thanks!

Labels: economics, nova, virginia

Yesterday, I mentioned that the main point of this weekend's field trip was to attend the Virginia Geological Field Conference in Marion, Virginia.

We arrived on Friday night at Hungry Mother State Park, and got some background information and logistical direction from the trip's leaders and the various officers of the VGFC. We also got some sobering news about how Virginia budget cuts will affect the Division of Geology and Mineral Resources... but more on that tomorrow.

On Saturday morning, we headed out to examine the geology of the Pulaski and Saltville thrust blocks, two of the slices of Paleozoic sediments that got shoved bodily northwestward during the Alleghenian phase of Appalachian mountain-building. The point of the trip was to examine the structure and stratigraphy of these two thrust sheets, in an attempt to compare and contrast them. Both are an example of "thin-skinned" tectonics, where sedimentary strata are deformed (folded/faulted), but they are disconnected from the tougher underlying "basement" rocks (the crystalline rocks of the North American continent beneath). Sliding along a big basal fault called a decollement, these sheets of sedimentary rocks created the northwestern fringe of the Appalachian mountain belt; a zone called the "fold and thrust belt." (This is in contrast to the "thick-skinned" style of deformation exemplified by the Blue Ridge province immediately to the east, in which the basement rock is itself deformed, and shoved up on top of these younger sedimentary strata.)

Here's two of the three field trip leaders: Loren Raymond (holding map) and Bill Whitlock (talking into the microphone), giving us relevant details for our first field stop:


Fred Webb (the third trip leader) used the same technique of large graphics as an aid in explaining the local geology. Here, he explores the geology of Saltville, VA, from a scenic overlook:


Here's Fred and Loren using another visual prop to illuminate the distribution of sediment types (Knox dolomite versus Moshiem limestone) on a farm in the Rich Valley:

Does anyone else out there use large visual aides like these on field trips? I think it's a pretty good idea.

There were a lot of people who attended the conference: over 120! Here's the crowd at the Saltville Overlook stop:


...and the throngs of geologists shutting down traffic on the way to another stop:


...and still more geologists all over the right-of-way at our final stop of the day:

Kudos to the trip organizers for coming up with a coherent way of running the trip with so many participants!

So why were we there? ...To look at these deformed sedimentary strata, and increase our understanding of the deformation mechanisms that accomodated strain during Appalachian mountain-building. Here's a look at the Max Meadows tectonic breccia, a zone of crumbled rock at the base of the Pulaski Fault:


Just above the breccia, the rock is still pretty deformed. Here's some intense folding and boudinage in dolostone & shale layers:


At another location, Honors student Hope W. shows a fault in the Nolichucky limestone:


In other places, folds were the main variety of strain observed in the rocks. Here, we see this in the Honaker dolomite (with elbow for scale):


Ditto for this exposure of the (Cambrian) Nolichucky limestone (enthusiastic caver for scale):


After a superb lunch put on by a church group, we strolled out in some karstic fields in the Rich Valley. Here, several field trip participants drop down into a sinkhole:


I was interested to see that there were a lot of Mississippian-aged evaporite deposits in this corner of Virginia. Saltville's salt was from the Maccrady Formation, as is this gypsum (note fingernail scratch mark):


Here's the spectacular final outcrop of the day, where we looked at deformation within the Cambrian-aged Nolichucky and Honaker Formations, as well as the Mississippian-aged Maccrady Formation they override at this location on the Saltville Thrust Fault:


Of note to you environmental types out there: Saltville was not only the "salt capital of the Conferderacy," but it was also the site of the very first Superfund site (due to dumping of mercury as a byproduct of soda ash + chlorine production).


And I'll just conclude the photo section of the post with a couple of photos of cool spiders we saw. Each of these arachnids is a good three inches in length (including legs):

I think the upper one is a 'garden spider.' The bottom one is silver! I've never seen a silver spider before...


All in all, it was a good day in the field. We returned pleasantly tired and hungry, and had dinner at the Hungry Mother State Park "The Restaurant". Over food, we discussed the pros and cons of field trips like this, and slept well that night.

I was particularly pleased to meet up with and hang out with folks like Cy Galvin (part of my pre-GSW dinner group), Jon Tso (Radford University), Pete Berquist (Thomas Nelson Community College), Amy Gilmer (Virginia Division of Geology and Mineral Resources), and Chuck Bailey (College of William and Mary). Pete, Amy, Chuck, and I are all W&M geology department alumni. Chuck mentioned the good news that he will soon be joining the geoblogosphere too -- watch this site for an announcement of his (surely to be excellent) geology blog as soon as it goes live.

Labels: arthropods, conferences, field trips, nova, stratigraphy, structure, valley and ridge, virginia

This weekend, I spent three days on an extended field trip down to southwestern Virginia with NOVA adjunct geology instructor Chris Khourey and four of my Honors students. We left Annandale on Friday morning, and made our first stop at Willis Mountain, Virginia, site of one of the most productive kyanite mines in the world.

Here's a Google Map of the mountain:


The Kyanite Mining Corporation was very gracious in hosting us. I'd particularly like to thank Mike Morris, who took two hours out of his day to show us the site and the mining operation.

Why mine kyanite? It's used as a refractory mineral: that is, one that won't melt under high temperatures. A lot of their kyanite is heated in kilns to produce a second mineral, mullite. The mullite is even more stable than kyanite in high temperature refractory situations. (It won't melt until it hits over 1800 degrees C!) Additionally, they cleverly saw up big blocks into dimensional stone for countertops and the like.

The kyanite mined at Willis Mountain is in a quartzite which also includes a fair amount of pyrite and hematite. We heard about the different procedures used to extract the non-kyanite minerals so that their end product is relatively pure and of constant quality.

Here's Mike showing the overall anticlinal shape of the deposit:

It's a plunging anticline, as you can probably make out from the Google Map terrain view up top.

Some of the dimensional stone, which I think is pretty spectacular:


Close up of the kyanite (light blue, on left) in the dimensional stone.


Nearby Baker Mountain also hosts kyanite deposits, which show a deeper blue color (Mike wasn't sure why, but suggested that chromium may be responsible):


Inside a huge storage building where the mullite (white powder at our feet) is stored:


Atop Willis Mountain itself, showing the weathered kyanite quartzite exposed there:


Honors students ask questions of Mike:


Mike and Chris standing near some fresh boulders of kyanite quartzite:


It wasn't all metamorphism and mining... I also noticed these nice raindrop impressions in a drying mud puddle:


After lunch atop the mountain, we hopped back in the van and hightailed it for southwestern Virginia, on our way to the Virginia Geological Field Conference. More on that tomorrow.

Thanks again to Mike and the good folks at the Kyanite Mining Corporation for hosting our visit!

Labels: conferences, economics, field trips, metamorphism, minerals, nova, piedmont, teaching, virginia

In my new work with the Campus Landscaping & Beautification Committee, I've been asked to come up with a few locations for a pet project of mine. I want to create a series of "fake" geologic outcrops on campus so we can have a "fake" geology field trip without leaving campus. The idea here is to create outcrops (using real rocks) in contrived positions, so that students get experience with figuring out things like rock identification, relative dating, transgressive/regressive sequences, faulting, etc.

I got this idea from Matty (2006), which I stumbled across while xeroxing science education articles for an MSSE class this past spring. The basic point is to have clear, useful teaching examples that students can access outdoors (emphasizing those kinesthetic and naturalist intelligences), without having to deal with the costs (legal, insurance, gas, carbon footprint) of a "real" field trip.

As a first step towards coming up with recommendations about where our initial "fake" outcrops will be placed, I asked our campus architect for a map of the campus. I told him I would prefer one with topography on it. Sure enough, he gave me one with topography... and a 1-foot contour interval! I don't think I've ever seen a topographic map with that level of detail. Anyhow, it's a beautiful thing, and I wanted to share it with you. I've labelled the buildings with their two-letter call numbers. (I teach in the CT building, for instance, but my office is in CF.*) Check it out:

Comments on the map? Or on what you think ought to be included in a "Campus Geological Area"? You know how to comment...

* I hate these two-letter names. They are so utilitarian... Why must we call the CG Building "the CG Building," rather than Godwin Hall? That would be much more elegant and academic-sounding.

----------------------------------
Reference:
Matty, David J. (2006). "Campus landscaping by constructing mock geologic outcrops." Journal of Geoscience Education, v.54, n.4, p. 445-451.

Labels: maps, msse, nova

Here's two events you might be interested in, if you live in the DC area and are into the Earth sciences...

1) I'll be giving next week's Science Seminar at NOVA Annandale. I'll be discussing my geological experiences out west this summer in a talk called "Two Months of Rock and Road." It starts at 12noon on Friday, October 17 in the CE Building Forum, and will conclude by 1pm. Light refreshments served starting at 11:45am. Free and open to the public.

2) American Meteorological Society Environmental Science Seminar Series: "Ecosystem Health in a Climatically-Altered World: Is 'Species Rescue' Part of the Prognosis for the Future?" by Dr. Camille Parmesan, University of Texas, Austin, Texas. Friday, October 10, 2008; New Time - 10:00 AM - 12:00 PM, in the Russell Senate Office Building, Room 253 Washington, DC. Free and open to the public.

What sorts of climate-related and compound stresses are various wild ecosystems encountering? What impact are these stresses having on these various ecosystems? How might one characterize the resilience, or lack thereof, of these ecosystems to these stresses. For those with the capacity to do so, how are ecosystems adapting to changes brought about by climate change and other stresses such as development? What is happening to those ecosystems that are showing signs of being incapable of either adapting in place or moving elsewhere? How do the rates of climate change and other stresses affect the odds that certain ecosystems will adjust and ultimately, survive? Are there ecosystems that now require, or will require, special human interventions in order to prevent their collapse and/or demise? What would these interventions look like and are they governed by existing national policy?

Buffet Reception Following; More information online at http://www.ametsoc.org/seminar

Labels: dc, meetings, nova

This weekend, I took 14 NOVA students caving in West Virginia. We hit three caves in the vicinity of Franklin, WV, on Saturday. On Sunday, we headed out towards Spruce Knob to experience two terrific caves: Stillhouse and the Sinks of Gandy. Here are some photos (and a video) of those last two caves.

Stillhouse Cave:









The sinkhole out of which we crawled...


Whose helmet is that emerging?


It's Hope!


A Cecropia caterpillar (according to What's That Bug?) that Tiffany found:

Sinks of Gandy:

The crew poses at the entrance. Gandy Creek flows through the entire cave!






Exiting into the light and trees and humidity and cows:


Ricky Q, caver man extraordinaire:


Video of the final watery exit from the Sinks:

I had a great time on this trip: felt like we all really bonded and had a fun adventure. Thanks to all the students who went and to the Student Activities counselor who co-led the trip with me, Jessie Zahorian! It was fun!

Labels: caves, field trips, nova, travel

NOVA students: This is a reminder that I'm going to be leading a two-day caving trip through the Annandale campus' Office of Student Activities. The trip runs from 8am on Saturday, September 13 to about 7pm on Sunday, September 14. We'll be going to a series of caves near Franklin, West Virginia: Trout, New Trout, Hamilton, and Keys. We'll also drive out to the Spruce Knob area to take in Stillhouse Cave and the Sinks of Gandy (which has a river flowing through it). I've led this caving trip many times over the past 15 years; it's awesome. Last time I took students there was for a GMU GeoClub trip in Fall 2005. Some photos from that trip are available here.

There is space for about 15 students on the trip. The trip has a cost of $35, which covers all food except for Saturday's lunch (bring that in a bag). For dessert on Saturday night at the campground, I'll be fixing Grandma Bentley's famous peach cobbler. If you're interested in going, please contact Jessie Zahorian in the Office of Student Activities at 703-323-3484 or jzahorian [AT] nvcc.edu. First come, first served! Other denizens of the geoblogosphere: sorry, but it's only open to NOVA students.

Labels: caves, nova, west virginia

Hey there! Do you (a) live in the DC metro area, (b) have an MS or a PhD in geology, and (c) want to teach? Well, NOVA might have a job for you. We encourage qualified applicants to send a c.v. and a brief letter of interest to Assistant Dean Craig Jensen at cjensen@nvcc.edu. Mainly we're recruiting for next semester, but we also had an instructor bail out on us this semester, so there is in fact a Monday/Wednesday afternoon class which will have to be cancelled unless we find someone ASAP.

Labels: geology, jobs, nova, teaching

As of today, I'm now an Assistant Professor of Geology at NOVA. (I used to be an Instructor.) Yee-ha!

The Rank ladder at NOVA has four rungs: Instructor, Assistant Professor, Associate Professor, and Professor. With positive evaluations and the credits I accrued from my MSSE program, I qualified this summer to climb up a step. (NOVA does not have tenure; just contracts of increasing duration.) In another couple years, I'll be able to apply for promotion to the rank of Associate Professor, but I won't be able to make the jump to full Professor unless/until I get a PhD.

I'm a bit torn about the PhD: I feel like it's a research degree, whereas I'm not doing research in my job at NOVA. I'm an educator. And it's a fair bit of effort, that whole PhD thing: getting a degree specializing me to do research that I don't do. On the other hand, it sure would be nice to be finished with explaining to people that I'm not a doctor. And I'm sure it would help inform my teaching -to some extent- it's just a question of gains versus effort.

Time will tell; I get the feeling I'm going to start itching for another degree come next summer...

Anyhow, for the moment, I'm pleased with the validation of being promoted. Yesterday, I updated my main NOVA webpage to reflect the change. ...And the moustache.

Labels: msse, nova

Fellow DC metro area residents -- there are a bunch of geology events coming up in the next couple of months that you may be interested in. Everything* listed here is free and open to the public.

Next Sunday, August 24, I'll be leading an event called "Geology Along the C&O Canal," at the Lock 8 River Center from 10am until 11am. My plan is to give an overview of the Appalachian mountain belt, then focus on the Piedmont "chapter" of that story, using local outcrops to illustrate the rock types produced. I'm not sure if you need to reserve a spot or not; Call Bridget Chapin at the Potomac Conservancy (number at link above) to inquire about details.

Friday, September 5: "Geology Along the Billy Goat Trail," I'll lead this hike along the famous Billy Goat Trail, examining its exquisite display of metamorphic geology and geomorphology. 12:30pm-4:30pm. Reserve a spot through the good folks at the Great Falls Tavern Visitor Center.

Wednesday, September 10: first Geological Society of Washington meeting of the fall. Beer served at 7:30pm, and the formal program begins at 8pm. At the Cosmos Club in Dupont Circle.

Saturday, September 20: I'll be leading my "History Before History: the Geologic Saga of Washington, DC" walking tour as part of Walkingtown, DC. The tour runs from 1pm until about 4pm, and involves about 2.5 miles of walking from Adams-Morgan to Georgetown. Limit of 30 people; interested walkers should reserve a spot with Cultural Tourism, DC, the nonprofit group that sponsors Walkingtown, DC each spring and fall.

Sunday, September 21: For those who can't make it Saturday, I'll again be leading my "History Before History: the Geologic Saga of Washington, DC" walking tour as part of Walkingtown, DC. The tour runs from 1pm until about 4pm, and involves about 2.5 miles of walking from Adams-Morgan to Georgetown. Limit of 30 people; interested walkers should reserve a spot with Cultural Tourism, DC, the nonprofit group that sponsors Walkingtown, DC each spring and fall.

Wednesday, September 24: Another Geological Society of Washington meeting, but I'll be delivering a talk at this one. My talk's title is "Rise of the geoblogosphere."

Sunday, October 5: I'll be delivering a talk called "A Geologist's Perspective on Climate Change" at the Chinn Park Regional Library in Woodbridge, Virginia. 2pm-3pm.

Friday & Saturday, October 10-11: The Virginia Geological Field Conference, in Marion, VA. "Geology of the Saltville and Pulaski Fault Blocks" is this year's topic. *This is the one item on the list that is not in the immediate DC metro area, and also the one item on the list that costs money -- registration is $45 for professionals, $20 for students. Transportation, lunch, and guidebook will be provided. See more details on the website. If you're interested in comparing and contrasting two Valley and Ridge fault blocks shoved westward during Alleghenian mountain-building, this might be of interest to you.

Thursday, October 23: the Earth's birthday, according to James Ussher. 4004 BC to 2008 AD; does that make it 6012 years old? Or is it 6011 years old, since there was no year "0"? Tricky... Regardless, I'll be serving lithosphere/asthenosphere cake/pudding to NOVA students in celebration of the day. (I posted on visiting Archbishop Ussher's church here.)

Wednesday, October 22: Another GSW meeting. Same time, same place, but this time I'll be back where I belong: in the audience.

Friday, October 24: "Geology Along the Billy Goat Trail," I'll lead this hike along the infamous Billy Goat Trail, examining its exquisite display of metamorphic geology and geomorphology. 12:30pm-4:30pm. Reserve a spot through the good folks at the Great Falls Tavern Visitor Center.

If you're into geology and you'll be around, I hope you'll join us on one or more of these events.

Labels: blogs, climate change, CO2, dc, geology, global warming, gsw, nova, piedmont

I spent a fair bit of today updating the "Scientific Illustrations" page on my NOVA website. I'll be adding a few more images there in the next week or so, including another commissioned set, but I figured I'd mention it here now, since I've practically gone cross-eyed working on it all day.

Labels: art, nova, websites

NOVA students: I'm going to be leading a two-day caving trip through the Annandale campus' Office of Student Activities. The trip runs from 8am on Saturday, September 13 to about 7pm on Sunday, September 14. We'll be going to a series of caves near Franklin, West Virginia: Trout, New Trout, Hamilton, and Keys. We'll also drive out to the Spruce Knob area to take in Stillhouse Cave and the Sinks of Gandy (which has a river flowing through it). There is space for about 15 students on the trip. The trip has a cost of $35, which covers all food except for Saturday's lunch (bring that in a bag). For dessert on Saturday night at the campground, I'll be fixing Grandma Bentley's famous peach cobbler. If you're interested in going, please contact Jessie Zahorian in the Office of Student Activities at 703-323-3484 or jzahorian [AT] nvcc.edu. First come, first served! Other denizens of the geoblogosphere: sorry, but it's only open to NOVA students.

Labels: caves, nova, west virginia

This map was in this morning's Washington Post. The red dots are currently-existing coal-fired power plants. The black dots with the central stars are proposed future coal-fired power plants.

Labels: CO2, coal, dc, energy, environmental, nova

On Monday, my Physical Geology students and I experienced a magnitude-2.0 earthquake during our final exam. The hypocenter was 1 km south and 6km down.

I pulled out the geologic map of the Annandale quadrangle (1986) by Avery Drake and A. J. Froelich to check for faults in that area. Here's a scan of the map:

You can see our campus in the northwest, and I've highlighted the epicenter of the quake with the red and green concentric circle. Interstate 495, the Capitol Beltway runs north-south through the center of this area. To the south and east of NOVA's campus, you can see that there's a mappable thrust fault (the Red Fox Thrust) which dips to the northwest, presumably under the epicenter and under the campus. However, the map provides no information on the angle of dip of this thrust. Is it steep enough to get to 6km depth a mere ~3km north of its surface trace? (The map's cross section shows it dipping at about 52 degrees, but that's pretty speculative.) Or if the dip is shallow, is there a deeper (perhaps parallel) thrust underneath it? (There is none shown within the map area, though there is one to the north of campus that dips to the north -- making it unlikely to be the culprit.) Alternatively, was Monday's quake caused by a new fault? Perhaps a normal fault which cross-cuts these Paleozoic thrusts?

No new answers -- only more questions...

Labels: earthquakes, news, nova

A quick update here on yesterday's "final exam" earthquake:

The USGS has upgraded the magnitude to 2.0, which seems more in line with what my students and I felt. They have also indicated the depth of the hypocenter as being about 6 km.

Talking to other faculty over the course of the day yesterday, I learned it was felt strongly across campus. Hardly surprising, considering we were essentially on top of it. My colleague Nancy Chamberlain wrote me an e-mail describing her experience: "It was a bang, a shake and a rattle. I flew out of my office exclaiming an earthquake... I was told someone dropped something upstairs but it really was an earthquake! I grew up in California and 10 miles off the New Madrid fault in St. Louis... I know an earthquake when I feel one!"

The Survey has also posted a few additional maps. For instance, to establish context, consider this map of historical seismicity in our area:

Labels: earthquakes, nova

Three-quarters of the way through my Physical Geology final exam this afternoon, the room shook and a low rumble propagated through our building. The students, many of whom were in the area on 9/11, instantly looked up with a very concerned "Was that a bomb?" look on their faces. To assuage their fears, and because I've previously heard similar rumbles coming from our HVAC ducts, I told them that it was just the cooling system, and not to worry.

Turns out I was wrong: it was a small earthquake with an epicenter about 1 km from here (we're about 1 km west of Annandale proper, and the USGS suggests it was 2km southwest of Annandale; see map below).

Almost on the epicenter of our own little quake! For us east-coasters, that's a big deal!

WTOP reported on it (Thanks to Ron Schott for forwarding me this link).

Here's the USGS quake page on the event.

Here's the Maryland Geologic Survey's seismometry. (source of image above, which is in Eastern Standard Time, not Daylight)

Here's the Washington Post's (brief) treatment of it.

I've gotta say, Ron Schott's up on it -- within an hour of the seismic event, he had e-mailed Tuff Cookie and I to ask about it. Pretty prompt! Thanks, Ron.


Update: Here's the Google Map showing the epicenter (green arrow). I've circled the building where I was giving the exam in the green circle:

Also: Here's the intensity map as it looked after I logged on and completed the "Did You Feel It?" survey:

Labels: dc, earthquakes, nova

Here's a photo of one of the cool things that my Honors students and I got to see on our recent trip up to Buffalo, New York (for the northeastern section meeting of GSA ):

That's an original, signed edition of the William Smith geologic map, brought to the meeting courtesy of the Buffalo Library. It is one of only two in the United States; the other is at the Library of Congress. The map found a home in Buffalo (of all places!) thanks to Chauncey Hamlin, the head of the Buffalo Museum of Science (then called the Buffalo Society of Natural Science) from 1920 to 1948. During his tenure, he assembled a collection of first editions of many seminal scientific works. First editions of Charles Lyell's Principles of Geology and Herbert Hoover's* translation of Agricola's De Re Metallica were also on display at the conference.

* Yes, that Herbert Hoover, at least according to Wikipedia.

Labels: geology, history, maps, meetings, nova

Here's another transcript of one of my field trips, again from uber-dedicated student Jill.

--- T R A N S C R I P T --- B E G I N S ---

Prince William Forest Park - Field Notes
Hike April 6, 2008
Paper due: Sunday, April 20th

Transcription Note - I apologize for the lack of words, at times. We were so near the river, the background noise of the river made it difficult to transcribe. Also, it rained during the morning. It was not the best day for a hike, but the weather outsmarted all of us that weekend.

Valley - Quantico Creek - Main Creek
South Fork - Main Tributary

(Tape #2?)

Field Notes - Weather: Raining...Callan cautions us about being nice to one another in the rain...

On Trail Observation - Top of high hill - rounded river gravel mixed in with sand & clay

On top of another hill - we will talk about it.

Volcano erupting signage. - Hawaiian volcano example. What it would have looked like 500 million years ago. Chain of volcanic offshore islands spewing out lava. As time goes by subduction is bringing those to the edge of North America until they eventually collide. Then all igneous rock - basalt rock gets slathered onto the edge of North America. Ex. - A snowball. New basalt rock is packed onto the edges - younger material added onto the edges.

Continents (low in density 2.7) never subduct. Oceanic crust subducts (2.9 vs. 2.7). Whenever the two butt heads, oceanic crust loses. Result is isotopically dated rocks which make up the continents and ocean floor. Ages are wildly different - 4000 million years (rocks which make up the continents) vs. 200 million year old (ocean floor). There is a huge difference. Continents are 40 times as old as the oceans.

Oceanic crust is constantly getting destroyed vs. continental crust which is constantly getting preserved.

Oldest rock is in the Northwest Territory of Canada.

Old Rag mountain. Rock from Old Rag is 1 Billion years old. 1 Page handouts. 1st event - Grenville Orogeny intruded granites into the crust. Granites are a symptom of mountain belts/building. And the granites cooled and became Old Rag. The Iapetus Ocean Basin was opened up. Cracks opened up into that granite into which mafic igneous rock (basalt) squirted into those cracks. Hiking up Old Rag - narrow little slots - which are those cracks. Floor is made up of dark colored, fine grained rock whereas the sides are coarse grained, light colored granite.

All that transpired before the stuff we are talking about today.

Volcanic rock is underneath us. We eventually will see it. First we will see sediments that accumulated at the bottom of the Iapetus Ocean right next to the volcanoes. Then at lunch today we will see some of this volcanic rock, itself.

We will get to see the rocks that made up volcanic islands.

We are at the boundary of sediments and the island arc further east.

Stop - signage. Small lake, dammed valley Sign about the Fall Line. 2 Virginia physiographic provinces meet. Region of the 1) Piedmont 2) Coastal Plain (as day goes by)

Boundary is the Fall Line. Coastal Plain is made out of very loose sediments, not stuck together in to a rock; loose gravel, loose sand, loose mud. Therefore, it is very easy to erode away. It is easy for water to strip it away.

Whereas the Piedmont is made out of hard rocks. (Like the ones we are gong to spend most of the day looking at). As water is draining from the Appalachian Mountains in the Atlantic Ocean, it is easy to strip away coastal rock and hard to strip away the Piedmont Rock. And, as a consequence, the boundary between the two you tend to get rapids and waterfalls. Those rapids and waterfalls line up on a line from Southwest towards Northeast - we call that line the Fall Line.

Here is the fall zone. The image on the left is a Geologic Map. You can see the difference in colors along the water. Coastal Plain layers vs Piedmont Plain layers. The Coastal Plain is draped on top of the Piedmont like a blanket. (see diagram). The deepest, therefore the oldest part of the Coastal Plain is a series of rounded river gravel. OK? Ring any bells? That is what we are looking at back there...these gravels. So, that is actually part of the Coastal Plain draped on top of the Piedmont. Right here we only find it on tops of the highest hills, but as we head east, it is found at lower and lower elevations. So, what we are going to see as we get down at the bottom of the hill - we are going to see our first little waterfall. Where the water of the South Fork of Quantico Creek which is the creek that carves this valley here where that is falling over some of these hard, difficult to erode rocks. And, then as we get down into Dumfries this afternoon, we are going to move out on the Coastal Plain itself where it is going to be very flat and the rock layers are very easy to erode. It is going to look very different - and it is a major theme we are going to discuss more over the course of the day. Since the sign is here, I figure I had might as well say something about it.

Stop. Our first actual outcrop of rock. I wanted to give you guys a chance to check it out. Outcrops are where we actually get to see some of the Earth is rock formations at the surface - and - you would think they would be more common, but they really are not. One of the reasons for that is we are trying to do Geology in the East. Out West, there are no plants, so all the beautiful rocks are exposed with these ugly forests that cover up the beautiful rocks. So, you only get to see the rocks where the forests have been stripped away. Like here, where a stream has cut down to reveal the rocks or sometimes when we build a road underneath. So, on the East Coast we are largely limited to the rock exposures that are in creek bottoms or in road cuts. We are at the creek bottom of the South Fork Quantico Creek coming out of that little lake from the dam upstream there. I want you guys to take 2 minutes. What you are going to do is examine them. I want you to make observations about this. I do not expect you to come up with the whole geologic history...

Little patches on the surface. Those are not rocks. Those are a symbiotic relationship between a fungus and an alga, right here where it is wet. Go.

So, yes. Yes, what is causing that? Something? The water. When these outcrops are first revealed they have nice angular edges like over here next to David. As the river flows over them with time they get worn down so they get nice and smooth. We will see some really cool smoothing out features downstream like the one, Kathy, you were noticing on that sign. Yeah, we will see some of that later on. Uh, Tee, what did you notice? OK, little sharp edges...OK...breaking...everything is parallel. We see this parallelism in the rock and that extends out to the stream making these little ridges of rock that extend out to the stream... (We will get to that - hold that thought). First, I want to talk about this parallelism that we are looking at here. Jill, what are we looking at here? Foliation. Right. Folio comes from the Greek word for plant or leaf - leaves on trees...(two choppers overhead go by...)

Foliation - originally folios to describe leaves and then eventually used to describe paper or books (a foliated structure...pages in a book parallel to one another is what we are seeing here in the rock). Something layered. What is it that is layered in the rock? Sediments from the breaking down of those mountains? Let us back up. You are right, but I want to make it a little bit simpler. What are rocks made out of? Minerals, right. What we are seeing here is the minerals all lined up in a certain direction. What force could line those minerals up? Pressure from what? A tectonic collision. The North American Continent pushing in this direction and the volcanic islands pushing in this direction. Let us go back to this idea of these two plates colliding - one is a volcanic island arc and one is the North American continent squishing together - this stuff got caught between - a sick analogy...a cute, little fuzzy kitten chasing a butterfly out in the meadow. Then it runs out into traffic on Route 66 and a big Mack truck comes along from one direction and a cement mixer comes from another direction and they collide head on and the kitten gets caught I the middle. The kitten changes its shape as a result of that collision - the kitten starts off with little kitten bones and fur all oriented in different directions, and as the two trucks collide, the bones get aligned perpendicular to the two trucks' collision direction. This is the mangled corpse of these sediments of /in the Iapetus Ocean. They have been crushed. They start off in all types of different directions. I will use my hands to represent two different directions - and then they rotate to the only stable configuration possible. Picture a bunch of papers on your desk. Push your hands toward each other and the papers end up lining upright the closer you put your hands together. The minerals here are all upright - all standing up essentially vertical that is..............See how straight this thing is? (A rock used as an example).

Break...then...

...bubble. OK. Did you guys see that in the back? OK, say again, speak up... "...crack in the rock and water filled in it, warm water and it crystallized into quartz." Right, and how do you know it was deposited by water? What is the clue that is telling you that? Hydrothermally deposited quartz. This white color is due to little tiny bubbles of water in that quartz mineral crystal. That is a sure indicator that that was originally deposited in a crack. Now, however, it is only the little chunk, just like that; then there is another little chunk there and another one there and there and there... They are a little bit pink because they have been stained by rust. Notice how they all line up in the same direction, too. Like this thing here is 7 cm wide by 40 cm long. Compression coming in East to West making everything line up North to South. Now, let us talk about the original sediments that got crushed here. (The so-called kitten). There are three rocks here in my hand; three different sandstones. 1) White quartz sandstone, 2) pinkish arkose (potassium feldspar) 3) greywacke - gray - all made of sand. This one is exclusively quartz. This one is a mix of minerals and has lots of potassium feldspar. Greywacke is a mix of sand and mud. It is a dark, gray color (clay as well). If I asked you to pick one of these three as the original source of these rocks before they got squished, which would you pick? Greywacke. See the color? If I put these three down, the one that blends in the most is the gray one, right? Now there are some other things influencing the color here, but yeah, if you zoom in on these rocks you will notice little grains which were originally sand and mud in this ancient, dead ocean - The Iapetus Ocean. When the tectonic collision happened, a lot of the mud reacted, becoming mica. Mica is another mineral, and a defining characteristic of mica is sheets; flaky sheets lining up one way once again indicating again that squeezing direction.

Zeta (sp?) was asking about some fractures cutting across, like here. See the fractures? There are a bunch of brittle features cutting across this rock. These rocks were squished in a flowing way and then later they were broken by brittle fractures. So, these brittle fractures may be related to the uplift of these rocks, over time. I do not know, or cannot say specifically if it is related to some tectonic cause.

But we know (with certainty) that that happened after the rocks had cooled down again. During mountain building, these rocks were hot and flowing. After mountain building, they cooled down and that is when they broke. To get these rocks to flow, they would have had to have been heated up to 350 degrees Celsius or so. Maybe higher. We will see evidence down the way of partial melting of these rocks. Partial melting yields granite magma. So, that is another symptom of mountain building. So, you have to get the rock up to 450 degrees Fahrenheit (when wet) in order to get it to melt. Using the Principle of Uniformitarianism, you can say they once were molten based upon how we know such rocks form today.

Greywacke. David - greywacke is from Old German for grey rock.

Making the distinction between a sedimentary rock and metamorphosed sedimentary rock...layers of sediment. You do not end up finding these big, long flaky bands of quartz...presence of all this mica. We do not get big deposits out there in the actual world where mica accumulates in big layers. We get layers of mud. So, the mica itself is a metamorphic mineral. Also, we do not see any continuity. As we look along the way here, we do not see that we can detect one layer of coarse grains or one layer of sand, mud, or anything like that. Instead, we see a sort of smeared-out looking feature. These rocks appear smooshed. What would you add to that, David? (The mica here is the metamorphic mineral, not a sedimentary mineral...B word....boudinage...)

Boudinage. French for sausage. Describe a rock layer that has been broken into sausage like segments. Right here, look at this you guys. 1,2,3,4,5 sausage links. This quartz vein is broken (as a brittle phenomenon). Also, the flow was pinched out along the breaks. There are pinched out ends, like a string of sausages all in a row. This occurs at 10-15km depth from crust...right at the transition between brittle behavior in the upper crust where rocks break, and more flowing behavior in the lower crust. Brittle means breaking. Flowing is like silly putty or bread dough.

So, I wanted to elaborate on something. See picture...4 parts. Something we can deduce about these rocks. A preserved sedimentary structure called graded bedding: layers of rocks that are coarse at the bottom and fine at the top. No graded beds here today, but at the Billy Goat Trail, you will see graded beds. That tells you how these sediments initially accumulated. I am correlating these rocks here with the rocks at the Billy Goat Trail, based on similarities in their mineral content, and my knowledge of the area. I'm saying these rocks exhibit all characteristics of Billy Goat Trail rocks except we do not see any graded beds preserved here. In the Billy Goat Trail, there are a few lucky areas where we see graded bedding preserved. Why do I care about graded beds? Graded beds are deposited by currents flowing along at the bottom of the ocean. (Picture of turbidity currents). These currents are very dense, sediment rich flows, that go along the bottoms and they slow down. As they slow down, all the sediments caught up in the rolled up water settled out. The stuff that settles out first is the big stuff. The stuff that settles out last is the light weight, really fine-grained stuff. So, you end up getting these graded beds forming. Those formed down in a location like this, down in the deep sea in what we call an abyssal fan or a submarine fan, where sediments are coming off some land mass piling up in the deep sea making graded beds of greywacke. Again, greywacke means nothing more than a mix of sand and dark mud. So, that is what this used to be. Then it got crushed up. When did it get crushed up? When the Iapetus was closing, good. As the Iapetus was closing (let me pull out another graphic here) it was a scraping up all that sediment. OK, the subduction zone was going down the hatch, but the sediment on top of the oceanic crust was getting scraped off. It was building up into a big pile; a big, jumbled pile of sediment. That is analogous to a bulldozer moving over the ground scraping up a big pile of dirt in front of it, OK? Where the bulldozer is like the island arc, and then in front of the continents are the sediments it is scraping up. OK? So, that is what we are on here. Really, these rocks here are the big pile of muck that got scraped off the subducted plate and then later it got squeezed between the islands and North America. So, we call this big pile an accretionary wedge. Now, Dean, you were talking earlier about California and San Francisco. San Francisco is still on an accretionary wedge. The difference between Prince William Forest Park and San Francisco is, Prince William Forest Park then had that accretionary wedge caught between two continents; Africa and North America, and it squished. Whereas San Francisco, it just filled out. It has not been squished between two continents, yet. Give it another 50-70 million years, something like that. OK. Questions? (Why the silt...? C. - What silt are you observing? Does that just look like it is going into the hills?) What was stable in the middle of the mountain belt is no longer stable. The mica is rotting away. In fact that is why over here, when I was running my fingernail through these little grooves, there is a groove there to run my fingernail through. The mica is soft and it rots away really easily, so it ends up etching out. And, the quartz is very stable and so it does not erode away easily and that is why it makes these little ridges. So, guys if you have not felt this for yourself, come put your finger on the rock and feel this yourself. That is why, like, on the drive down I was noticing these big white boulders on the drive in. Those big, white boulders are made of quartz - it is stable. It does not break down over time. That is why when you go to the beach; the beach is made out of quartz sand. It is not made out of feldspar sand, mica sand or anything like that. It is quartz. Quartz is the stuff that lasts. (Student questions Callan. C. -- Yeah, right. Black beaches are where you are really very, very close to a basalt source. And, there are not...there is not ....adequate time to break down all those unstable minerals, so the beaches built up making those black minerals there. So, we are finding that there are some black minerals even on beaches here on the East Coast, but, the majority of it, when it is a nice mature beach, is quartz sand.)

One of the exercises I had Jill do this semester, and I had Dave do last semester, as well as the rest of my Physical Geology class is that I give them a little, bite-sized Snickers bar and they have to suck on this Snickers bar. The chocolate dissolves away very readily in their mouths followed by the caramel. The nougat lasts about 10 minutes or so. But even after you suck on this thing for about half an hour, the peanuts are still there. Peanuts do not dissolve, right. Peanuts are like quartz whereas all the other ingredients in the Snickers are more like other less stable minerals.

(Student talking about some observation). C.- Actually that is a great observation. Let us take that one step further. Imagine, now this creek here is not a creek but a road and you are driving down it. You take this turn and you take it a little too fast. Which way does your body get pulled? Right, towards the outside of the curve. So, basically, during flood times the creek comes in and slams into that wall right there and strips away the plants and strips away the leaves and strips away the dirt and it exposes rock there. Whereas the rock that is underneath the hill here is not getting hit head-on by the force of that creek. So, it fills up with sand, dirt, and leaves over time. I did hold this rock down here and I just wanted to point something out, it is a little bit difficult to see because the stupid thing is all wet, alright, just like us. But, this is a foliated metamorphic rock. Does everyone see the plane of foliation? So, if I were to line it up here with the regional foliation, it would look like that. Alright, but this one is loose so we can pick it up and examine the plane of foliation itself. And, there are little black needles there on the surface. Do you see those little needle-like minerals? They are needle-like mineral growths. Do you guys see them there? It is almost like if somebody took a bunch of chopsticks and dropped them on a desktop. The chopsticks were in this random orientation because they would be parallel to the surface of the desktop. OK? If I took all your pens and dropped them on top of someone's notebook, they would all splay out on top of that notebook but some might be pointing this way and some might be pointing that way. That is what you are seeing here in this plane of foliation. These are amphibole minerals. And the amphiboles are randomly oriented within the plane of foliation. Pass it around. I know David wants to get a good look at that with his lens. Make sure he gets that. Great. Good. (David and Callan have discussion about amphibole, spelling, etc...David asks, does the random orientation of the amphibole suggest that was it done when the pressure has been released. C. - No, I think basically that what we have here is we have flattening. Remember what we talked about was the different types of deformation; folding, faulting, and I think I said squeezing or flattening. These rocks have been flattened. And what we see is that the dominant pressure direction was coming this way and then the rocks, in order to accommodate that (here we go – here is my little Nerf ball. Yeah, I left my kitten at home...) Um, they are getting squished in this direction. Right now the Nerf ball ends up basically elongating outward this direction and growing in this direction, as well. So, like, you think about three dimensions, these right here are growing and this one...whhish....gets squashed. So, I think what is happening here is that flattening stress is causing the amphibole as they are growing...they ca not grow in this direction. It is like, try growing if the building collapsed on top of you. But, you can grow in this direction.)...we will see a couple of them here today. ...Dave, unfortunately it is not...it takes certain elements to make the amphibole, so unless those elements are present in the original sediments, you do not make it. Dave - OK. Student - Do you want to leave this here? C. Yeah, that is why I brought it down. C. - No, I would not break it, I would just kind of stash it over there underneath a tree or something so maybe in a year from now I can find it.

Another segment...

...you take away the fact that we have determined that these used to be sediments in the Iapetus Ocean basin, and then they got squeezed due to mountain building. Due to that Taconian Orogeny...this episode of mountain building that we mentioned back in the shelter. Taconian stands for the Taconic Mountains of New York, alright. (see the one page handout that I gave you). Dave - What are the compass directions here? C. - Essentially, North/South and then, East/West - squishing. Now is it actually that? Well, no its North/Northeast, but close enough. Dave - it is a good observation to make in the paper the direction in which the squishing seemed to happen. C. - Yeah, I would say that would be a great observation to make in the paper. Um - it may not have been originally in that direction though, because remember a later collision happened. That later collision also squished. So, it is like remember the kitten, Mac truck, cement mixer pile-up we had earlier? Then along comes a tank and crashes into it, OK? And then that ends up rearranging everything again. Dave - could the magnetic poles have changed here? C. - Uh, yeah, but we have no magnetic signature in these rocks. We are just trying to get in our head how - Dave - You did say North and South...C. - Yeah, so we are using modern day directions but then again North America would have been rotated around in a different position, so it is a complicated question. Sounds like it is a simple question but it is really not! Another student asks a question. C. - You do not have to understand about magnetic poles to understand what we are talking about...Dave - ...unless it is present day...(Callan brings discussion back around to)...yeah, that is all we have to work with and that is what is going to be most readily available to you guys. So, again, the one thing to think is this foliation essentially lines up on the same line from the Appalachians, basically from Georgia...Dave - OK, yeah, that is a better way to go, yeah. C. -....so, that, that is due to this first collision...Dave - ...Appalachians...to the ocean, like that? The Appalachians have...to the Ocean, like that? C. - Well, the Appalachians would be parallel to this. So, essentially we are looking at Maine up that way, Georgia down that way...ok, West Virginia, that way, and then the Atlantic out this way. Uh, I was in the middle of making a statement there and I got derailed.

(Dave - If these clay minerals had all been aligned and micas formed in the first compression, and they were tilted up in whatever orientation, and a second collision took place and it came from a different angle, would all this seem likely to get reoriented or would it preserve some of the old orientation? C. - Probably you would have some preservation and some would get reoriented, depending on where you have little bits that poked out, those being more susceptible to being re-rotated.) Um, that being said the overall structural grain of the Appalachians is this North/Northeast to South/Southwest direction, so, I mean I think we can just sort of simplify things - well, it may be an oversimplification - we can simplify things by saying these collisions all essentially came in one after another from the same direction. First, these volcanic islands during the Taconian Orogeny. There was a second collision that happened, later on, we are not really going to talk about that today - called the Acadian Orogeny. And then finally, Africa hit and that was the Alleghanian Orogeny. So, all these different orogenies were episodes of mountain building.

Oh, I know what it was that I was going to ask! When does the Taconian Orogeny happen? Well, Dana, that is just great. How did you know that!? She says 460 million years ago is when this actual collision took place. And, she is right, but, she is just pulling that number out of thin air. You can not see it. Student - she got it out of the papers C. - OK? Yeah, you are on the right track. OK, radioactive decay. So, certain minerals when they form, they take in radioactive isotopes, and then if you can go and you can say that that mineral is a mineral that only formed during an orogenies, then you can say, "Ah ha!" All you have to do is look at the radioactive isotopes that remain in that mineral and compare it to what they decay into. So, in this case the mica here has been isotopically dated. What they did was they looked at radioactive potassium 40 that is present in that mica and they compared it to the daughter product - the stable daughter which is called argon 40 And, the mica as we said earlier formed during metamorphism ...was a good state for the orogeny. The date is 460 million years ago. We are going to see a granite today, and the granite has a date of 464 million years ago. OK, so it is basically the same age. And it tells us about the same event, and granites, you remember, are another symptom of mountain building. So, we have got a really good view on the orogenies then by dating these two independent, isotopic systems. The metamorphic mica here, and then the granite that resulted from partial melting. I will remind you of that again when we get to the granite, OK? Alright, that is a good point to keep in mind. Student - So what overall type of rock is......C. - No, this is not granite, granite is much lighter color and granite does not have this foliation. Um - so this is a metagraywacke. All right. Meta, the prefix meaning change, and, greywacke telling you what it originally was.

OK., I know everybody is hungry, so we are going to hoof it. We are going to walk down to the Cabin Branch Pyrite Mine. We are going to be walking across and along the South Branch of...

...stop and maybe point out this point bar......do not feel like you have to take notes. OK, I’m not going to go over anything really important...


(Tape #3) After lunch...

OK, so granite you remember is produced by the partial melting of other rocks - remember I showed you that other diagram where you had a bunch of starting minerals and then the light colored ones sweated out - they melted? Whereas the dark colored ones stayed behind. So, here, it is a metagraywacke that is being partially melted. And the minerals that are easiest to melt those metagraywacke are quartz, feldspar, and mica - some of those are basically melting out and they are leaving behind the darker colored minerals. Ok, so we are producing these granite blobs and these blobs of magma are moving up to the crust and eventually they are settling down and crystallizing into granite. Remember we call these blobs plutons. So, here in this diagram which is part of your handout, I have got a diagram showing you some igneous plutons, OK? So that bodies that were magma and have crystallized into solid igneous rock, like a granite - OK, here is one pluton, here is another pluton - they cooled underground. Now, basically these plutons are these wet batches of magma and they are moving up through the crust. What happens to the pressure that is on them the higher up they go? Yeah, it is released and as a result they erupt - basically the granite separates out and the stuff that is most readily removed leaves the granite. So, think about a bottle of soda - did anyone bring a carbonated soda? David did. David brought a ginger ale. So, when he popped the top on that, OK, it started off as just liquid, but when he popped the top he released the pressure on the liquid inside. And as a consequence, a gas that was dissolved in the soda came bubbling out. Carbon dioxide came bubbling out of the solution. The same thing is happening to this granite which, remember, originally was magma. As it gets up to shallower depths in the crust, gases and things start coming out of it. It is leaking fluids into the surrounding rock. OK, so it is intruding into this rock and so these fluids and gases are penetrating the surrounding rock. Some of those fluids and gases would probably be water vapor, another one would be carbon dioxide, another one would be hydrogen sulfide, um a bunch of different fluids, OK? And one of the things that these fluids are taking - with - them, (I think I have got my mouth.../sandwich repeat) - OK, the fluids are carrying with them metals. Alright, metals readily dissolve in those fluids that are carried out of the granite by the fluids. And as those fluids penetrate the surrounding rock, they cool down and the metals are deposited there. Frequently, the metals are - they glom onto sulfur. Sulfur joins up with lots of different metals and then it settles out in this big sulfide deposit which surrounds the granite pluton. OK? So, it is kind of like a halo or an aura surrounding the pluton is this big aura of sulfides deposits - sulfur mixed with metals. OK? So, some sulfide minerals contain galena, some of you are familiar with galena, it is beautiful, it is got this silver luster, and these little cubes. Um, another really important one is pyrite. Pyrite is nothing more than iron sulfide. The chemical formula for iron is Fe - the chemical for pyrite is Fe. OK, it is nothing more than iron mixed up with 2 sulfurs. For every one atom of iron, there are two sulfurs bonded to it. And that makes this mineral called pyrite. Then, what color is pyrite? Golden. Yeah it is sort of this golden color and it looks a lot like gold, if you do not know what gold looks like. Um, it is got that same golden luster. Well, they were mining this pyrite here. We have already said it is not gold so why are they mining it? What on earth is the point of pulling up fool's gold from the ground? Gunpowder. C. - Gunpowder. So, basically, they are not interested in iron, they are interested in the sulfur. The main thing they are using the sulfur for is gunpowder. It is also used in many other industrial applications like making soap and refining glass and other things like that. But, not nearly as exciting as warfare. Jill - Civil War? C. - The pyrite mine right here actually started in the aftermath of the civil war, and then it actually hit a fever pitch during WWI, when there was a really big demand for gunpowder. So, they were pulling lots and lots of pyrite out of this mine, processing it to extract the sulfur and then using it to make gunpowder. So, geologically why there is a mine here is that the granite is essentially sweating out all these fluids. The fluids are rich in dissolved metals. It is just like when you sweat, there is salt in your sweat. And if it dries out on your shirt, you get a little white crust left behind on your shirt, right? So it is the same thing her except for instead of salt crustiness left behind, you will see a metal crust. So, the same granites that were produced during the Taconian Orogeny were sweating out these deposits of pyrite into the crust. Later on, people came along and said, "Hey, we can make use of that, let's make a mine here. We will dig into the hills and dig out as much pyrite as we can." So where we are right now is we are sort of geologically on this dome surrounding one of theses plutons, OK, we are in this sweaty armpit region. So, what I want to do now, is I want to go and find some pyrite and look at it. So, what we are going to do is walk back over here to this area where there was nothing growing. And, we are going to go look for some pyrite. Does that sound workable? Eventually we will come back to this place, so if there is something heavy you do not want to carry, you can leave it here and then come back and pick it up again. (Student question - inaudible. C. - The granite pluton was. Yeah, so the granite - the body of magma which would eventually cool into a granite. We will visit that granite this afternoon). (Student - So it is coming out because it...C. - the granite was, yeah, and as it is getting to shallower depths in the crust, it is devolatilizing, so the various gases that are dissolved in it are coming out. So, it is starting off here during partial melting, then the granite is organizing itself into these blobs, they rise through the crust, as it rises it is sweating out into the surrounding rock all these mineral deposits. Alright, sometimes as it moves into the crust, the crust cracks open and you end up getting veins of pyrite or veins of hydrothermal quartz. Some of those veins of hydrothermal quartz have gold in them, actual real gold. Including in the northwestern corner of this park, and by the Billy Goat Trail in the Great Falls area. So, there are gold bearing quartz veins in this area and they are coming from the same source. They are essentially being sweated out of this granitic magma. (Student - ...keep that in mind if the dollar keeps going down. C. - That is right, we will start mining our National Parks.) OK, other questions? Let's go.

(New Spot.) Now, I'm going to start talking now about some of the environmental damage that the mine caused. In this area, where the ground was near the mine operations, they were filtering the lower grade ore, you know the stuff that did not have enough pyrite in it, and they just kind of dumped it, alright? And, that is what we are sorting away here, right? And that pyrite is then soaking out here at the surface of the Earth in water, and that water is oxygenated water. And, those two ingredients end of completing a reaction of water, oxygen, and pyrite. Water, of course, is hydrogen and oxygen. Oxygen is just oxygen. And, pyrite is iron and sulfide. So, basically, after that reaction you end up getting iron mixed with oxygen and hydrogen which is rust (FeOOH) and sulfuric acid (H2So4). So, two things are being produced here due to the weathering of the pyrite; rust and sulfuric acid. Rust is what is making the soil so darn red right here. It is staining everything red. Look at David's boots right now - they are getting all soaked in this red mud. Alright, the other thing is sulfuric acid. What is the effect of sulfuric acid that you see right in this area? Basically, most plants cannot grow in super acidic soils; soils that are essentially drenched in sulfuric acid. As a consequence, nothing grew here for a really long period of time. It was basically a day of awakening - completely environmentally degraded. So, the ground was basically an empty wasteland and then the Parks said, "OK, we have got to clean up this mess." So, they took a series of steps to essentially reclaim the land. OK, this is something that frequently has to happen where they do mining - reclamation - basically making it look like a decent landscape again. And, what they did was they brought in a lot of limestone. Limestone is made out of calcite, and that reacts with acid. So, basically it is a buffer through the sulfuric acid. And, when they laid down all these limestones in the area, some of them are dissolving away as soon as they get set down. They are taking away some of that acid. It is kind of like Tums in the landscape - that is a great way to think about it? Did you have some Tums this morning? David - no. So, it is like Tums through the landscape and it is working better in some areas and not as well in other areas. It is not working so well right here. There is still a lot of sulfuric acid right here in this area which is why you can actually go and pick up rocks there. There are no plants growing out. That is thanks to the acid. Same as that little patch there at the end of the trail - there is nothing growing there. That is so weird for the East Coast to have an area where there are no plants growing. That tells you there is something seriously messed up with the soil underneath.

One of the things I would like you to do, is I would like to have you test the pH of the waterways. You might want to clean off your hands first, because the way you are going to be able to read this thing is to check the color of the paper. Alright, this is a little pH paper here. It is going to change different colors depending on the pH of the water you put it in. Now, you want to make sure you are putting it in relatively clean water otherwise you will get sediment on this which is going to give you a false reading. OK? So, I'm going to give everybody a little strip here. You can choose to test this water here, somebody should go test the water of the South Fork, and somebody should retain their strip so we can test the water of the Main Fork of Quantico Creek. OK, so we want to collect data at several different points, to several different iterations at each point, so we have reliance on the data and then we will share everything we get.

Everybody tests. OK, what do you have? 6! What do you got? (Everyone testing.)

Results 5 or 6 - somewhere between a 6 and a 5....slightly acidic. He just put it on his tongue and it is a 7. So, your tongue is pH neutral, which is a pretty good thing for your body. So, he has a reading of between 5-6 so that is just slightly below neutral, so this area is slightly acidic. That is not as acid as it once was, but it is more acid than just what regular old water would be which is 7. So, as the number gets lower in pH level, the more acidic. Higher is more alkaline. End of segment.

...sweating out of a granite pluton. Then the fact that this was mined for awhile for the purposes mainly of making gunpowder, and one of the elements that make up pyrite is sulfur, and then the breakdown of that sulfur at the conditions found at the surface of the Earth here; mixing it with water and oxygen, making rust and sulfuric acid, and then the Park surface had to treat the area by putting down essentially the geologic equivalent of Tums with limestone chips in order to get rid of the acidity. Oh, and another point that we could make here that the plants that actually are growing here are pine trees. These are acid tolerant plants. Their needles, themselves, are acidic. So, their needles are dropping - so look underneath those pine trees. You see the carpet of needles underneath, right? Those needles are essentially making that soil more acidic and that makes it harder for other plants to grow there, OK? They make a special kind of acid called a tannic acid. It is the same thing if you brew your tea for too long - it is a sort of bitter thing and it makes your stomach hurt. That is essentially what is going on over there with those trees. OK, let's move.

Testing pH at new location. (Dave - So are these the rocks that they dumped? C. - Yeah, so this is the ........that basically have water coming through them. The water is...)

OK, so I imagine we all do not want to stand here for too much longer. Did everyone see that vein of pyrite that Topher found? Time to work our way back to the path.

New location.

...C. - I'm going to turn upstream on Quantico Creek. (Jill - Confluence of Quantico Creek). We are going to look for a place to cross Quantico Creek. We want to be on the other side of it.

New location.

C. - I want to point out we are at the confluence here. So, here is the South Fork of Quantico Creek, which flows under the bridge we just walked over. Right, here coming into the main stream of Quantico Creek, the two merge right here (Jill - the confluence) and they flow downstream. Where we actually want to go is where there are a bunch of branches across the creek down there. It is probably only 200 yards from where we are right now. All right, but, unfortunately there is no great way to cross the creek right here. So, we have got to go upstream a ways, until we get to a good creek crossing. As far as a bridge and cross over. David, if you want you can wade across, but, I do not want to make every...

New location.

...flow. Where were these lava flows accumulating? Jill - Volcanoes. C. - Volcanoes, where were the volcanoes. Jill - the island arc. C. - Yeah, the chain of islands offshore, you remember, ancestral North America about 500 million years ago. Then, subduction narrowed the ocean basin between them, and eventually they got added on to the edge of North America. Now, how do I know these are lava flows? Great. Color, texture, and maybe the mineral content. Yeah, so there are some good color indicators here. What color is this greenstone? It is a very descriptive name - greenstone. It is probably in the Old German for - just kidding. So, greenstone is metamorphosed basalt. Remember basalt is what is coming out of the volcanoes today in Hawaii. (Student - asks question. C. - Well, we call it magma if it is below the surface and we call it lava if it is above the surface. Once the lava cools we have to give it a rock name. The typical name we use for the dark colored rock is basalt). Basalt is what made up the oceanic crust and what made up these volcanic islands. So, when the basalt gets metamorphosed it undergoes chemical reactions and those chemical reactions turn it green. The main green mineral here is called chlorite - it is basically a green mica. There is also epidote. Right here there is a pistachio colored mineral. You guys see that one? It is sort of a bright green? Filling in little veins over here? It is epidote. Alright, so basically, I know Topher is going to ask about this - the "take home message" is that these were once lava flows that got metamorphosed. How do we know that? The Principle of Uniformity. When you see lava flow that gets metamorphosed in the world today they change color into a green color. The reason is that they grow chlorite minerals and epidote. ....yeah, well there is some other stuff. Remember these have gotten squished. So, a lot of the original layering is lost. They are foliated. They are foliated and again it is that squishing effect. OK, I want you guys to come and look at these rocks here. There are little white circles in the rocks. Oh, see these white blobs here? OK, what is going on here is the same thing we were talking about earlier. When you release pressure on a lava, it causes gases to come out of solution. Just like when David opened his Canada Dry the bubbles formed. When lava erupts at the surface bubbles form in the lava and gases come out, right? If those bubbles do not pop before the lava sets up into rock they are preserved as little holes in the rock, like Swiss cheese. We call those vesicles. The vesicles have gotten filled in with mineral deposits. Those mineral deposits are known as amygdules. Amygdule is for the Latin for "almond." So, these were originally decided to look something like almonds - set in a piece of bread, like that. There are some really nice ones over here with mineral deposits. Generally the minerals that are filling them in are quartz, well Let us just say, quartz. David - something about popping. C. - ...if they do not pop, it leaves hole. Later on that hole could get filled in with a mineral deposit. This is important. The bubbles form as gases are coming out of lava, then some of those bubbles pop, we do not have any evidence of it. But, some of the bubbles do not pop and those bubbles get filled in later on with mineral deposits which make these little white blobs in the greenstone. And, notice that these little white blobs are not perfect spheres. Up here they appear kind of like this. Why is that? They got squished - like a little kitten's eyeball. That is due to that tectonic squishing. You can see that they are all basically squished like this line up at the plane of foliation. Alright, they lay exactly parallel to the plane of foliation. That is why the sphere became a pancake. So, they are little pancake shaped fossil gas bubbles from a lava flow. We call them amygdule because they got filled in with mineral deposits. If they were still empty holes, we would call them vesicles. ( ...you can see epidote down here in veins... come down here with David and you can see them.)

Barely audible due to noise from river. C - ...ancient volcano island rock... ...Chopawamsic....Dave and Callan in a lot of discussion about the volcanoes, flows, etc...evidence of it all...Callan sticks to history of Virginia....at one time you could have walked from Ohio to Morocco. Now those rocks were once sediments in the ocean deposited way down...

...discussion about potholes....barely audible. The role in carving it out. When water come flowing through here, there is a vortex of water. Filled with sand, silt, and it acts as liquid drill bits. Layers of quartz and mica, quartz and mica. Quartz stands out in high relief. Sand gets in there and preferentially eats away the mica. So, that is a pothole and potholes are one of the ways that streams are cutting down in areas of waterfall where they are adjusting from one level to another level. Alright, Let us go ahead and work our way back to the trail and we are going to start climbing uphill, towards the bathroom...

OK, so here we have another tree that is tipped over, and it has brought up a nice, fresh sample for us. We can see here more of that gravel that we saw when we first started on the trail today. This is not a rock. This has not been stuck together into a rock - it is just loose gravel...David - it is a root ball, right? C. - Yeah, it is a root ball of a tree. You can pick up the loose grains of sediment, and let it run through your fingers. Actually, I encourage everyone to do this. You will feel that this is a mix of sand and clay, and the clay will feel very sticky on your hand, and then these nice, rounded pebbles and cobbles of mainly quartz, OK? Most of which is present here is quartz. Student - Sand and all that is what is left over after the quartz was left. C. - Well, basically, you said it yourself. This is a very poorly sorted sand pile. This is a mix of different grain sizes, which indicates that it was dropped very rapidly. Now, what does the rounding tell you? Jill - it was well sorted. C. - ...well traveled. It is not well sorted, it is poorly sorted. Yeah, the rounding tells you that this quartz cobble started off somewhere far away and then it traveled a long distance to get here and as it traveled it got more and more rounded. This one must have started off a little bit closer. Alright, because this one is a little bit more angular. And that is typical of river systems because river systems end up draining a whole area. Rocks are dropping into them from far away and nearby and they are both tumbling downstream together. And, Jill, that is how you interpreted this, right? Jill - yeah, well no, sorry, I was off in a zone. C. - Jill, how would we interpret this deposit, how did this form? Jill - Well, basically, it came off of an uplift, and it traveled downward, and it was deposited into a system of water...C. - OK, what kind of water? Jill - Probably very fast. C. - OK, good, why do you say that? Jill - Because, it looks like they are rounded, I mean...obviously they passed through...Student - ...it is the size of the rock...C. Yeah, it is the size. Student - it is a well-rounded big rock. C. - Yeah, it is obviously a well-rounded, nice big cobble of quartz. And, it takes a lot of water energy to move something this size. Jill - Yeah, definitely. C. - OK, good, so what kind of body of water has the energy to move big cobbles like this? Jill - River, a river. C. - Yeah. Rivers, OK? Because we just saw, in fact, I just destroyed my vocal chords trying to shout over - rivers have a lot of energy. Whereas a lake does not have so much, a swamp - less. The ocean has a fair amount of energy, but you generally do not get big cobbles like this in an ocean because as soon as rivers flow into the ocean, they slow down, and then they drop all these things, and then they carry maybe the sand and the mud further out into the ocean. Those are all that really make it into the ocean. So, this is a river deposit. And, when you think about it you might think it is a little bit weird, because we were just down at the river and we just hiked uphill, and now at the top of the hill we see these river deposits? What is going on here, Cathy? Cathy - The river was once up here? C. The river was once up here, she says. These were not recent flood deposits. So, these are ancient, and the reason I know that is I can come up with a rough date for these deposits based on fossils that we find within this same gravelly unit. Now, this gravelly unit here, do you think it is a particularly good setting for preserving fossil remains? Callan hits the “unit” with large cobble, again and again. C. - Do you think that is good for a fossil? All right. Think about the river here. As these things are moving along, all these boulders are smacking into one another and grinding around. This is a lousy environment for preserving fossils. It is a miracle that we have any fossils at all from this unit. The fossils that we do have from this unit are very poor and they have been broken up a bit but we can still identify them and they are dinosaur bones. Alright, we found 3 or 4 different dinosaur bones from this one unit. There are some sauropod fossils, sauropods are the big, sort of lumbering, vegetarian dinosaurs with the long necks. We found some of their teeth and some of their leg bones. OK, there is a species called Astrodon johnstoni, it is the state fossil of Maryland. Basically, Astrodon means star-tooth. Think about your molars in the back, and you have these little points for grinding. There is a series of five radiating ridges for grinding up vegetation. So, Astrodon johnstoni. Also, we found some raptor fossils in here. At any rate, these dinosaur fossils date back to the Cretaceous. Cretaceous is a period of geologic time that ended at about 65 million years ago. It started at about 120 million years ago. The best estimate for an age on this unit is about 100 million years old. One hundred million years ago a river was flowing along this area, and that river was meandering. It was cutting in at a cut bank and it was depositing materials on a point bar. This is an old point bar deposit. OK, remember we saw piles of gravels that look a lot like this being deposited down at Quantico Creek today. So, this river was no longer cutting down, it was simply meandering back and forth on the landscape. Now, something must have happened between what we were just talking about at the base of the hill, and the deposition of these river gravels. We have this great big mountain range that had gotten built up, right? The size of the Himalayas - what happened to that? It was eroded down to essentially a flat level, and over that flat level, this river was meandering back and forth depositing gravel. OK? Then at some point after that what happened? Sea-level dropped and what did the river do in response? It started cutting down again and carving new valleys like the valley that we spent most of the day hiking through, OK? So we have evidence here of a higher sea-level at some point where these rivers were meandering along depositing gravels as they flowed eastward from the west out toward the young Atlantic Ocean. The Atlantic Ocean, by the way at this point, was 100 million years old. The Atlantic Ocean was born 200 million years ago and these gravels were deposited 100 million years ago, therefore, that is about 100 million years into the history of the Atlantic. One of the reasons that I’m able to say that these rivers were flowing from the west to the east, is we find signatures of rocks that we know only come from the west. Like we find pieces of granite that we find from the Blue Ridge Province. And these Blue Ridge granites have blue-quartz in them. Which is an indication that these are from the Blue Ridge Province. Yeah, there is some nice blue-quartz in this sample to right up there by my thumbnail. It has sort of a purplish sheen to it. You guys see that? The other thing that sometimes we find here is quartz cobbles that have a trace fossil right in them. That tells us that that came from the west, the river brought it this direction deposited it here, therefore that river was flowing from west to east. The same direction the rivers are flowing today. Now when the Appalachians were real, real young, it was the opposite. The rivers were starting here in the highlands above our heads and draining off to the west. Student - that is why you find Appalachian rocks way out in the west - west of us...C. - Yeah, there is some fairly compelling evidence in fact that the Petrified Forest of Arizona was buried underneath Appalachian sand and mud. In Arizona - so we are talking Mississippi sized rivers draining these young Appalachian Mountains, transporting the sediments to the west, and then basically they snuffed out a forest out there in Arizona. We can go and pick up a certain mineral from those sands, and that zircon has a chemical signature that is more analogous to the Appalachians than it is to any local source out there like in the Rockies. So, it indicates again at that time the mountains were here and the lowland was there. Who has got their handout handy, the one with the colored map on the back? Callan explains map....Kp designation which stands for Cretaceous. The sub p there indicates the Potomac and this is called the Potomac group. They are exposed up and down the length of the Potomac and you find them on tops of the highest hills. Same unit atop Tyson's Corner. You find it on top of Mt. St. Alban where the National Cathedral is. You find it on top of Mount Pleasant in D.C. - river gravels, river gravels, river gravels....Say that three times fast. So, this surface on top of which the river gravels are deposited is a period of missing time. The last geologic evidence we have in this area is the intrusion of granites. That happened around 460 million years ago, and then the next thing that is recorded in this area is the deposition of this gravel on top of it, which happened 100 million years ago. So, 360 million years of geologic time are missing in this area. We can say nothing about them from Prince William Forest Park. You have to read the geologic record to find out what is missing from those 360 million years. OK? Student - How come no one could think about water or erosion? C. To erode away a Himalayan sized mountain range takes a fair amount of time, and so it took a long time to grind down those mountains to that level. Plus, during the Cretaceous, the world was quite warm and sea-level was quite high. There was very little glacial ice, if any, and at that point then you have this combine effect of having ground down the mountains plus sea-level being high and that is when it deposited gravel all over this area. Wow, so this is like a little mud stone, right. Student - I get extra credit. C. - I would not call this a schist, it does not have nice physical minerals, but I would not mind calling it a mudstone. This is a little clast of mudstone and this is very typical of some mudrock layers that are typical out in the Valley and Ridge Province and that would be consistent with the story of basically transporting eastward. That is rose quartz there...OK, the first thing we are going to do when we get back to the visitors center is use the restroom, and then we are going to go and visit a fossil tree and that fossil tree is growing during the same period and it was probably growing along the banks of the river.

This was deposited by a river after the Appalachian Mountains were ground down. It is Cretaceous in age. It never experienced mountain building. If this had gotten caught up in that collision in would not be a loose pile of gravel, mud, and sand, it would be a rock. What would we call this if this had gotten cemented together into a rock? A conglomerate. Nature's version of cement with big chunks set in a little fine-grained matrix.

And, I do not really know what that means, I mean....

...on the trail today you are not leaving behind your skeleton, but you are leaving behind traces of yourself. Right? So, the thing that this Skolithos worm tube tells us is that it is a piece of the Antietam Formation. Antietam Formation is a big sandstone unit that is out on the western slopes of the Blue Ridge. And you can find them near Antietam National Battlefield, where the bloodiest battle of the Civil War was fought. You can also find this same rock along portions of Skyline Drive and there is an area where David and I have hiked near 66. There is a nice big exposure of it near Front Royal. So, basically it is telling us that the river transport direction was westerly - consistent with the blue-quartz. Sedimentary transport from west to east.

...Fossilized Bald Cypress Tree. It is really not in any danger of being degraded or anything like that, but it is in danger of having stuff grow on it. It is the mineral itself that will break down. All quartz. The quartz was derived from Cretaceous river gravels...And as it met this wood, it percolated through the wood, soaked into it, a chemical reaction took place, and it precipitated silica in place of the wood. This similar process has occurred in the Potomac Formation. In Washington DC, when they were digging out the foundation for the Ronald Reagan Building, they found more of these there. Also, at the base of the Mayflower Hotel, they found these fossil tree trunks down there. And, what do all these areas have in common? They basically have these cretaceous, Potomac Group river gravel deposits. So, you can imagine growing along the banks of this ancient river, Cypress Trees. How would you recognize a Cypress Tree if you saw one today? Yeah, Bald Cypress, and they have got these weird structures that rise up out of the waters. They call them knees - Cypress knees. They poke up above. I noticed in a place up here there are little tension gashes and they are filled in with silica, too. You see that - these little gray, blobs cutting across up there? So, it is like the tree itself is being deformed. It is fracturing and then the silica is depositing in those cracks. Yeah, so David is asking a question I do not have the answer to which is where is all this silica coming from in the groundwater? The groundwater has various things dissolved in it at various places at various sources, you know, that is about as specific as I can get. David - Silica does not dissolve easily in rainwater. C. - Right. David - It has to be warm to dissolve.

C. -...when things die, they just tend to rot. Fossilization is a very rare circumstance, when an organism gets preserved over time. Yeah, so wood tends to rot, so things eat it, beetles eat it. Well, one of the interesting things that is contrasted in this specimen as opposed to the one they found underneath the Reagan Building, or underneath the future site of the Reagan Building, is that one is jet black. This one is very, very light colored, it has got rusty. It basically suggests more oxidized conditions in terms of its preservation. Student - Where is the other one? C. - The other one is in Rock Creek Park. If you take my Bedrock of DC Geology Trip, then I will show it to you. It is jet black and it is also got pyrite preserved in it. Pyrite is again something that breaks down in the presence of oxygen as we have seen today at the Cabin Branch Pyrite mine...where it broke down into rust and sulfuric acid...so, it is more of a typical preservational environment. Low oxygen is more likely to be preserved. So, this is somewhat anomalous, but it is a beautiful specimen. What I just love about it is the grain of the wood here.

(Last segment - Granite outcrop in creek)

...water to get in there. What happens to water in the winter? It freezes. The water freezes and expands in volume by 9%. So, that opens up that crack a little bit wider. That means it is more than likely going to break down pieces, and when those pieces get broken out you carve out a little valley in the rock, right here. The quartz itself is stable, right? But, the neighboring area is not necessarily as stable. So, if you look around this area, you can actually see this quartz vein has actually become this little valley here and it narrows down...Do not take my word for it, come see. Now I want somebody who has never taken a class with me ever before, what is this? A sausage! What is the word for sausage? A boudinage! Oui! A boudinage! Alright, there is a beautiful boudinage in the last quartz vein, there. Now in order for boudinage to happen, it has got to be hot. It has got to be under lots of pressure, right? That is something that I said happened about 10-15km depth in the crust. So, that boudinage must have taken place during mountain building when this rock was still deep and hot, after the granite had already solidified because you ca not break a granite. It went through the quartz vein until the granite was already solid, right? So sometime after 460 million years ago, but before 100 million years ago. (Dave - Does the orientation of that, uh, boudinage tell you anything about the forces? C. - It well could. I have not measured its orientation myself, so I have not even thought about trying to put that into a regional context. But, yes, orientation of different rock structures like foliation or dikes, um - joints which are what we call these little cracks in the rock - those all often tell us something interesting about the forces that went to work on the rock. Now where Adrianna (student) is standing, we see a really interesting feature. Alright, here this granite dike has been faulted. You see here? This crack is not just a crack, it is a crack on which the two sides have moved relative to one another. There is an offset here about 1 inch in this granite dike. And, look here, there is another segment and it is offset about a centimeter. And, then another one, and another one, and another one, and another one. Do you guys see that? It has basically been broken and the rocks over there where Adrianna is standing have moved probably about, you know, just judging from this alone, maybe about by 5 inches that way relative to the rocks where I’m standing. That is a brittle behavior, OK? That is strictly breaking the rock. Alright, you do not see any real evidence of flow, there, OK, unlike the boudinage. (Background discussion/question...C - No, because this water does not have a lot of quartz in it. In order to get quartz to dissolve in water as Davis was pointing out earlier, it has generally got to be kind of warm to dissolve quartz better than cold water like this.) Student - What is the difference between a dike and a vein? C. A vein is just one mineral - like we saw epidote vein in the greenstone and we see quartz veins here. But, a dike is many minerals because it is an igneous rock. It is a tabular mass of igneous rock. And this is - this crack opened up, magma squirted into that crack, solidified into rock, and later it was broken and faulted. David - Wherever you see lines and stuff, you have faults. C. - We can only call it a fault if we have clear evidence of offset on either side. Still, like this one here maybe a fault as well, but I do not have anything good that tells me there is an offset on either side. Jill - So, instead of displacement in a rock, it is just a brittle behavior? C. - You might note that it is a brittle behavior that accommodates a displacement. The displacement can happen by flow or it can happen by breakage. In this case, it is breakage. Jill - It is a displacement? C. - Yeah, it is displaced. (...a 2 second bit of talking over each other/discussion back and forth between David and Callan.) C. - Cathy had a good question like did this happen during the collision? Alright, it is a great question. I would say that this is such a strictly brittle behavior (we can even see like little shards of the dike in there) right there along that zone, that I would say that this happened sometime after these rocks cooled down. And, earlier, I evoke this tremendous mass of rock overlying this location, right? 10-15 km of overlying rock that has been removed. Now, so does that mean that this rock, right here, has been exactly at this point three dimensionally in space through all of time and that there were mountains 15 kilometers tall on top us and have been beveled down to exactly this point? Or, did this rock start off 15 kilometers down and then basically uplift as erosion went to work on the landscape? Or, was it both? So, maybe it started off 7 kilometers down with 7 kilometer tall mountains. The mountains were eroded away, that means the crust is lighter and it pops up. Then more erosion goes to work on it. So, that means the crust is lighter and it pops up. More erosion goes to work - finally exposing the granite at the surface. David - are joints in granite often a loading and unloading feature anyway? C. - Well, a lot of joints in granite are unloading features. A joint is what you call a crack in the rock along which no movement has occurred. But, oftentimes we see that they are parallel to the topography. And these are distinctly not parallel to the topography. They are vertical. If we were to see a similar joint set running through the rock like this way, you know these rocks were under lots of pressure - now on the surface they are under no pressure. Sometimes we see granite actually expand, and then that thing fractures as it expands out, and those fractures then run like this, like an onion skin. That is stuff you see up in the high Sierras in California. Topher (sp?) was just saying he would been out there, up in Lake Tahoe - and then up in Yosemite to see these big granite domes, like Half-Dome, which are sheeting off layer after layer because the granite is actually unloading, and the sheets are just popping off. Are you making a movie of me? Jill - yeah. C. Just do not put it on You-tube or anything, OK? Alright, David noticed something cool, Let us turn our attention over this way.

Look at this. There are two intersecting joint sets here. Now, a joint set is basically more than one joint that is oriented the same way. So, we have got one joint that is basically going like this. OK, very regular. And, you have got another joint set that is going like this through the rock, also very regular. Their intersection produces these little columns like square columns of granite that go downwards, right. So, like we might actually see some up movement - no, none of them are loose. Well, anyhow, these things may be related to the unloading but if they were related to unloading, I would expect to see a third joint going like this through it basically divvying it up into tubes. We do not see that, but I expect it has something to do with tectonic readjustment during the uplift process. Alright, and after the rocks are cooling down and getting uplifted as the overlying rock gets stripped away by erosion, they crack, you know that is a stressful experience for a rock. It happens vertically, sometimes like 7 kilometers or 10 kilometers, something like that. Great observation. Now, what is colonizing those cracks there? Student -What? C. - Colonizing the cracks? Student - Lichen. C. Yes, and moss. Yeah, this is lichen. This is a crustose lichen, and this is a foliose lichen. Foliose lichen has leaves, right, like folios. And, the crustose is like crust on the surface of the rock. Um, yeah, because those cracks end up holding water, that is a good place for moss. Moss likes that - it grows along those cracks. You know, if I was to take a picture of just the moss here, to show you where the moss wants to cover up the joints...... (river is too loud).

How old is this granite? 464 million years old, + or - 5. That means somewhere in the range of 459-469 million years. OK, what else have you guys noticed? There are plenty of other cool things to talk about here? I'm going to climb back over there. C. - Good. I heard nickpoint, I heard waterfall, I heard pothole. OK, the river here is adjusting from a higher level towards a lower level. You can see that it is carving out a nice, deep valley downstream, whereas upstream we do not see that big of a valley. There is a valley, certainly, but its not a serious a size as it is downstream. There is a series of waterfalls downstream from here, and the river is adjusting to a ....level, over and over and over again. Somebody brought up the term nickpoint. I think you did. The profile of a river is like where it starts off at a higher elevation and then it is descending towards a lower elevation. Those little nickpoints are where the waterfalls are. Um, this is a nickpoint right here. This nickpoint is retreating in an upstream direction. Over time, the river will adjust, and basically will be cutting down in an upstream direction, and then the downstream area, if it gets too steep will try to get flat, by mass wasting which will widen the stream valley. Oftentimes we talk about the Grand Canyon haven been cut by the Colorado River. It is only partly true. The Grand Canyon was cut deeper by the Colorado River, and the Grand Canyon got wider over time due to a landslide, not wasting events. So, gravity does not like having a whole bunch of rock supported by neighboring rock. It is more likely to collapse. So, that is the same thing here. The Quantico creek cuts downward, and over time the valley has been widened and widened and widened. Sometime on your own come back to downtown Dumfries and see how wide the valley is, because it is quite wide. Alright, questions? Jill - Did you say earlier that was an example of columnar jointing? C. - No, I was just saying that the intersection of these two joints just end up making these kind of vertical four sided columns of granite. Like you take a block of cheese you go chop, chop, chop and chop, chop, chop. You end up having these little columns of cheese. It is not columnar jointing. It is a completely different process.

Where the moss was the first one to colonize this joint, so you can see that this joint is filled in with moss, and here there is frost wedging to get this expansion of the dike, and various other process have made a little deposit of dirt here in the crack. And, a seed landed in that dirt, and the seed took root. Is this an ideal place for a tree? Probably not. But, it is growing where it ended up. In time of really high floods, you know it is probably more than likely to be stripped away. Notice that the majority of the trunks coming off of this thing are all tilted in a downstream direction. OK, that probably happened during flooding. Um, yeah so, probably not ideal...

Jill - I have a question about nickpoints. Is it like the vertical cut in the waterfall? C. - A nickpoint is basically something we describe on a river profile. The way we recognize nickpoints is we look for water dropping from one level to another. Jill - it is not like an event...C. - it is a feature. Jill - ...it is a feature. C. - And, I would only be comfortable here saying this is one nickpoint here, and there is another waterfall downstream where you get another sort of 10 foot adjustment. I would say that is a second nickpoint. And, one of the neat things at Great Falls is that as you hike along the Billy Goat Trail is, when you go up to Great Falls you can clearly see one, two, three jumps in elevation. There are three nickpoints bunched together at Great Falls. Here, they are more spread out. Jill - but there was an event that created it, right? Callan - Basically, as sea-level drops a new water fall develops there and then that starts working its way upstream. So long as it outpaces sea-level rise it is going to keep propagating upstream. Dave - ...sea levels are rising. C. - Well yeah, I mean sea levels are rising, so lower nickpoints could get drowned and then there is not going to be any more erosion going on. Jill - so basically they are faults...they are faults? C. - No, a fault is a break in the rock in which movement has occurred. These are simply levels in the rock - the river has eroded down to this level, then as base level drops, OK, the river is now eroding down to this level. So, a waterfall develops here and then it moves upstream over time. But, the actual rock underneath is not necessarily faulting. Jill - OK.

Yeah, this is an interesting blob here. I'm noticing this shape. It juts inward here and it juts outward there. It appears to be faulted where this side has moved over to the right relative to that side. That side moved to the left. The way we typically describe these things is when you have a fault - say there is a fault running through here about like that, OK? You look across to the other side, and you use the direction that side tends to move. In this case, the other side looks like it went to the left. It's a left-lateral fault.

--- T R A N S C R I P T --- E N D S ---

As before, I would be pleased to hear any comments / insights / suggestions you might have.

Labels: field trips, nova, piedmont, teaching

It started raining in DC on Sunday, and it basically hasn't quit since then. Rock Creek is running high and frothy, and the Potomac has about seven times as much water in it today as it did 36 hours ago. The USGS has only one gauging station on the Potomac in the Piedmont -- at Little Falls, approximately on the DC/Maryland border. Here's what that gage's data (available free online from the Survey) tells us (as of last evening) about the river's recent discharge trend:

Labels: dc, nova, piedmont, rivers, sediment, water resources