Hello to the other geobloggers who read this blog!

I'm making my plans for GSA (Portland, Oregon) this week, and wondering if when we should get together for libations, conviviality, and rocks (and perhaps recording a podClast?). My talk is Monday morning, and I think I'll come out for a field trip the Saturday before the meeting. And of course the big digital innovations session is Tuesday. I may have to leave after that though... remains to be seen whether I can get people here to proctor an exam in my absence.

Anyone know a good pub in Portland? Anybody have field trip recommendations?

Labels: meetings, oregon

This is another photo from Saturday's hike. Unakite is rumored to be the 'state rock' of Virginia, though it's not in the state code. Regardless of its official status, it sure is a distinctive sight: An epidotized granitoid, unakite is identified by the distinctive pairing of pistachio-green epidote and pink potassium feldspar. There's some grey/purple quartz there too. In the mid-Atlantic states, it's only found in the Blue Ridge geologic province. Here, on the trail below Dark Hollow Falls in Shenandoah National Park, my friends and I encountered this lovely boulder of unakite bearing a vein of milky quartz.

The original granitoid was Grenvillian in age, about 1.1 billion years old. Presumably the metamorphism took place during Alleghanian mountain-building, between 300-250 million years ago. Unakite has been quarried in Virginia for use as a building stone, and can be seen as tiles on the first terrace of the steps leading from the National Mall up to the southern doors of the Smithsonian's National Museum of Natural History in Washington, DC.

Labels: blue ridge, dc, igneous, metamorphism, minerals, museums, smithsonian, virginia

Yesterday, I took a hike with some friends in Shenandoah National Park, and we encountered a bunch of interesting insects. I took a couple of photos, the best of which I'll share here.

Monarch butterfly caterpilar:


Moth Butterfly and hover-flies enjoying thistle nectar:

Labels: arthropods, national parks, shenandoah

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

Another in the photo/sketch series...

This is an outcrop I saw in the Teton range (Wyoming) this summer. It's a nice example of relative dating, I think...

Labels: art, geologic time, structure, wyoming

The Crazy Mountains are a range of mountains in south-central Montana, north of Livingston:

In this Google Map, you can orient yourself from recent posts by finding Bozeman, the Gallatin Valley, and the Bridger Range down in the southwest corner.

The Crazys are an Eocene intrusion, (Ar/Ar dates of ~50 Ma), and they are beautifully expressed on a geologic map as a radiating series of dikes around two central blobs of intrusive rocks (quartz diorites, etc.: dark pink on the map):

These igneous intrusions penetrated the Livingston Group, a series of volcaniclastic sedimentary rocks of late Cretaceous to early Paleogene age (hot pink on the map).

The day before my students arrived in Montana this summer, Lily and I took a hike in the Crazys, entering in the northern part of the range. We saw some cool dikes exposed along the road on the way in. Here's me pointing out the contact between a subvertical dike of porphyritic andesite cutting across subhorizontal layers of the Livingston Group:


Annotated version of the same photograph:


And here's a close-up of the rock making up the dike; mostly fine-grained and gray, but with some lovely big euhedral plagioclase feldspars as well:


That's about it for the geology I saw in the Crazys. Our hike kept us mostly in the forest, so clearly I'm going to have to go back some other time and spend more time there!

Labels: igneous, montana, mountains, sediment, travel, volcano

(deep voice) "Previously, on NOVA Geoblog..."

...We were looking at the structure of the Bridger Range in Montana, near Bozeman. We discussed the concept of Pumpelly's Rule, which suggests that outcrop-scale structures (meso-scale) can help us understand the regional structure (mega-scale), and that the asymmetry of certain kinds of folds can tell us where we are on that structure (vergence). [Link to post]



So the Bridgers are an anticline, overturned in the southern part of the range... but that's not the whole story!

Starting during the Miocene, the west began to widen. The Bridger anticline cracked in half along its axis and the western half slid down relative to the eastern half. The downdropped western half became buried in younger sediments, and that's the Gallatin Valley, where Bozeman is located. When the block of rock above a fault plane slides down relative to the block of rock below the fault plane, we call it a "normal fault." (It would be normal for a kindergardener to slide down a playground slide, but the reverse of normal for them to slide up it!)



A Google Map "terrain" view to show how this is expressed physiographically - Bridger Range on the east, downdropped Gallatin Valley on the west:



And, zoomed out a bit to get some more regional context on how Basin & Range extension has left its mark on the physiography of western Montana, eastern Idaho, and western Wyoming:



I've visited some of these normal faults myself (solid lines); the rest I'm just inferring from the landscape (dashed lines). Basin & Range extension is one of the main reasons the west is so beautiful: those wide open spaces with mountains rising to define the horizon...

(sigh) ...I'm glad I got to spend so much of my summer out there. I'm looking forward to it again next summer. But in the meantime, this is the first week of classes at NOVA, and I'd best get back to work!

Labels: faults, montana, structure

An article in today's Post explains more.

Labels: coastal plain, maryland, plants

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

by Anastashia Cuddihy*

Eleven miles south of Mammoth Hot Springs, and at the northern end of Beaver Lake in Yellowstone National Park, lies a geological wonder¹: Obsidian Cliff. Although it is only half a mile long, it has been a source of confusion and contentious debate for years.

Map of the Obsidian Cliff area (Google Maps):


Obsidian Cliff was formed when a rhyolitic lava flow traveled down the plateau and formed the 200 foot cliff. What is so unusual about the cliff is that obsidian is characterized by being a quickly cooled glass; the quick cooling prevents any crystals from forming, leading to a glassy rock. However, the bulk of the obsidian found at Obsidian Cliff is just that - a tall cliff made of obsidian - and it is far too massive to have cooled quickly enough to form obsidian in the 'traditional' way. Since there is no possibility that this amount of obsidian was cooled quickly, geologists theorize that the rhyolitic magma that formed the cliff had an extremely low water content, which would have hindered the formation of crystals. A feature found at the cliff that is associated with relatively slow cooling is columnar jointing. Columnar jointing occurs when lava shrinks during the cooling process, forming cracks, and it contracts to form 6-sided columns¹. Without the formation of crystals, the magma would have cooled to become the obsidian found in the cliff.

Columnar jointing at Obsidian Cliff:⁴


Another solution offered is that the lava could have come in contact with a large body of ice, such as a glacier¹. Upon contact with the glacier, the lava would have been able to cool rapidly and form the obsidian, although probably only at the contact margin. However the low-water-content explanation is the more widely accepted. Underlying the obsidian is a purplish-gray rhyolite, which is visible along the cliff face². Upon close examination of the obsidian, one can see the swirls left in it by the lava before it cooled¹.

Flow-banding in Obsidian Cliff obsidian:⁴

(also note the spherulites)

While Obsidian Cliff is not the only place in the park to find obsidian, it is most abundant at that site. Obsidian can also be found at locations called Tanker Curve and Cougar Creek.²

Obsidian Cliff is known for more than just being an anomaly in the formation of obsidian. Obsidian was prized by Native Americans for making tools, and there was no place better to find obsidian for these tools than Obsidian Cliff. Since obsidian fractures conchoidally and has sharp edges when fractured, it was best used in arrowheads and spears and blades for hunting¹. Scientists can use the chemical composition of obsidian (such as the concentrations of trace elements like rubidium and zirconium; See figure) to trace it to its source.

Scatterplot of zirconium (Zr) plotted versus rubidium (Rb) for 143 samples of artifact-quality obsidian collected in Yellowstone National Park.²


Archaeologists have concluded that obsidian from the cliff was being used as far back as 10,000 years ago, up until the arrival of Europeans in the area in the 1800's, when explorers found the Shoshone tribe using obsidian-tipped arrows³. Obsidan from the cliff has been found as far away as the midwestern United States, and it is inferred to have arrived there through the extensive Native American trade routes, where the high-quality obsidian would have been highly valued.

Obsidian Cliff is obviously an important site, both for American heritage and science. It gives us a wonderful idea of how the volcanic structures of the park work and how varied volcanic effects across the park can be. It is not suprising that a park with such a varied and explosive geological history would be home to such an intriguing structure.

__________________________________________________
* Rockies course 2009 student

1. http://www.nps.gov/yell/planyourvisit/upload/Yell250.pdf
2. http://www.obsidianlab.com/research/research_yellowstone.html
3. http://wyoshpo.state.wy.us/aamonth/2000.asp
4. Photo by Charlie Corrick.

Labels: volcano, wyoming, yellowstone

After a post the other day, Michael wrote in to ask for clarification of "Pumpelly's Rule."

AGI defines Pumpelly's Rule thusly*: "The generalization that the axes and axial surfaces of minor folds of an area are congruent with those of the major fold structures of the same phase of deformation."

We saw some of this same idea expressed in yesterday's annotated photo series featuring parasitic folds on larger folded (and boudinaged) quartz veins. There were bigger folds there, and then those bigger folds were decorated with little parasitic folds. The idea behind Pumpelly's Rule is that you could get a sense of what the big folds are doing by looking at the little folds. But even more revealing than parasitic folds at the hinge area of a larger fold are the little folds that you sometimes see on the limbs of bigger folds.

Depending on the sense of the asymmetry of these folds, we call them either "S" or "Z" folds. The parasitic folds are more symmetrical towards the apex of the fold, but more asymmetrial along the limbs. Check out this diagram to see how small S-folds and Z-folds relate to the larger structure of the main fold. Blue arrows indicate the relative sense of shear on each limb of the main fold:


Pumpelly's Rule suggests that we don't need to see the whole picture to understand what's going on. Simply seeing the areas of the diagram highlighted in red are enough to give a sense of the bigger picture.

So how does that relate to this photo, which prompted the question?


Behind me in the photo, you can see an outcrop of the Cretaceous-aged Thermopolis Shale, exposed on Bridger Canyon Road, in the southern part of the Bridger Range, Montana. It has some sandstone layers in it. These sandstone layers, with their high color contrast against the surrounding black shale, record a series of lovely S-folds. The strata here dip moderately to the west. The S-folds relate the sense of shear on the larger structure of the Bridgers: they suggest that the bedding here is overturned, and that you're looking at the eastern side of a big north-south-striking anticline. In the southern Bridgers, therefore, the overall structure is an overturned anticline. Hiking west & uphill confirms this interpretation stratigraphically: as you go up, you go "back in time," encountering older and older strata: from the Thermopolis into the Kootenai, into Jurassic formations like the Morrison, the Swift, and the Rierdon.



Moral of the story: small observations can have large implications.

Raphael Pumpelly made this observation in 1894, presumably during his tenure as the head of the USGS New England Branch. Pumpelly sounds like he was an interesting guy, leading expeditions in Asia when that was a seriously sketchy prospect. In addition to his Rule, he is honored with a mineral named after him, pumpellyite.

* If you don't have a copy of AGI's Dictionary of Geological Terms, a good resource for looking things up online is this Dictionary of Mining, Mineral, and Related Terms sponsored by Hacettepe University in Turkey.

Labels: cretaceous, history, jurassic, montana, mountains, structure, websites

50 years and 2 days ago, the Hebgen Lake Fault slipped, and triggered the Madison River Landslide. Here's the article I wrote about it for EARTH magazine.

By the way, someone already pointed out to me that Orion's a winter constellation... d'oh!

Labels: earthquakes, mass wasting, montana

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

Unannotated photo:


Photo with quartz veins outlined, highlighting boudinage and parasitic folding:


Photo with vein quartz boudins and folds highlighted in yellow:


Sketch interpreting stresses that produced these structures:


This nice example of ~horizontal shortening and ~vertical stretching is seen in metagraywacke muscovite schist with hydrothermal quartz veins, near Potomac, Maryland. It is located on the C&O Canal, just upstream from the bridge going to Olmstead Island and the Great Falls overlook.

Labels: art, maryland, piedmont, structure

Very clever! (a comparison of tobacco-doesn't-hurt-you and climate-change-denier arguments) Hat tip to Tamino.

Great resource. (For those who love to wallow in data and want the freshest graphs for their students.) Hat tip to ClimateSight.

Labels: climate change, global warming, politics

Wowzers.
Hat tip to Dave Petley.

Labels: hurricanes, mass wasting, taiwan

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

First Geological Society of Washington meeting of the new academic year
September 23
http://www.gswweb.org/
Dupont Circle, Washington, DC

Virginia Region of the National Speleological Society caving convention (but without the caving)
September 25-27
http://www.varegion.org/var/events/FallVAR/FallVAR.shtml
Battle of Cedar Creek Campground (Route 11, between Strasburg and Middletown, Virginia)

New York State Geological Association meeting
September 25-27
http://www.newpaltz.edu/geology/nysga.html
New Paltz, NY

Virginia Geological Field Conference
October 2-4
http://web.wm.edu/geology/vgfc/2009.php
Big Meadows, Shenandoah Nat. Park, VA

Labels: caves, gsw, new york, shenandoah, structure, virginia

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

All photos in this post by Rockies student Charlie Corrick.

Talking S-folds, vergence, and Pumpelly's Rule in the Bridger Range:


Hiking uphill and down-sequence in the Bridger Range:


Describing the Kootenai Formation:


Jared gets eaten by Big Mike:


Joel with a few columns of basalt:


Post-M.O.R.-tour, with the guide:


Victoria and a Triceratops horn:


Group at M.O.R., with Tyrannosaurus for scale:


Calcified bat, Lewis & Clark Caverns:


Inside the cave:


Beartooth Plateau:


Amanda enjoys the view:


Camp at Pebble Creek in Yellowstone:


Watching for wolves, Yellowstone:


Bison:


Obsidian at Obsidian Cliff:


Longhorned beetle that landed on our geologic map of Yellowstone:


More to come...

Labels: arthropods, dinosaurs, fossils, glacial landforms, mammals, montana, wyoming, yellowstone

Nora Noffke asked me to help get the word out about this cool conference... Here you go:
-CB

Microbial Mats in siliciclastic sediments from the Archean to present

May 21 - 23, 2010
Denver and Dinosaur Ridge, Colorado

Convenors:
Nora Noffke, Old Dominion University
Henry Chafetz, University of Houston

This inaugural conference presents an important geobiological review on microbial mats and the sedimentary structures they form in siliciclastic settings through Earth’s history, from the early Archean to the present. The meeting brings together an international panel of leading researchers to provide a state-of-the art overview of this field. This meeting is essential for all scientists interested in this rapidly growing field.The conference discusses modern microbial mats constructed by benthic cyanobacteria and other microbiota in aquatic settings. It will:

• explore the processes of microbial interaction with physical sedimentary processes;
• give an overview on the taxonomy;
• discuss the relation of the siliciclastic biogenic structures to stromatolites and;
• their distribution through time.

Topics include:

• early life,
• the rise of cyanobacteria,
• the evolution of microbial eukaryotes,
• the biological transformation at the terminal Precambrian,
• taphonomy of Ediacara fossils,
• influence of macroorganisms on microbial mats,
• extinction patterns, and
• stratigraphical significance

PROGRAM :
The conference will consist of talks, posters, and a field trip to Dinosaur Ridge.

Abstract submission:
The program includes talks of each 20 minutes and 5 minutes discussion, as well as poster presentations in the afternoon. If you are interested in a presentation, please submit your abstract for either talk or poster to Nora Noffke (nnoffke@odu.edu) or Henry Chafetz (hchafetz@uh.edu).

Abstracts should be unformatted. Abstracts are limited to ten authors, 100 or fewer characters in the title (including spaces), and 2,000 or fewer characters of body text (including spaces).
Authors will be notified via email of acceptance or rejection. Accepted abstracts will appear in the research conference abstracts volume.

Following acceptance, authors may wish to submit an optional extended abstract. Submission guidelines for the extended abstract will be supplied with abstract acceptance. The submission of abstracts opens September 1st 2009, and closes December 1st 2009. The notification of acceptance will be sent during December.

Special Publication:A SEPM Special Publication is planned for selected papers on this topic. Contributions to this volume are not restricted to participants at the conference. Please send an abstract of an intended manuscript to either Nora Noffke or Henry Chafetz. Invited manuscripts will be accepted until June 30, 2010 (firm deadline).

Labels: colorado, conferences, microbes, stromatolites

The Smithsonian's National Museum of Natural History, Department of Mineral Sciences invites the museum community to a memorial service commemorating the life contributions of Tom Simkin, the founding director of the Smithsonian's Global Volcanism Program. Simkin also served as president of the Geological Society of Washington. A memorial program will be held at Baird Auditorium on Tuesday, September 8 at 10:30 AM, followed by a reception in the Executive Conference Room. We welcome your attendance. Please send your RSVP (yes only) to Sally Kuhn Sennert (KUHNS@si.edu) by 1 September to help us make catering estimates for the reception.

Labels: gsw, museums, smithsonian, volcano

Lola helps me plan a winter break journey...

She goes berserk for large expanses of paper... A few minutes after I took this picture, the little brat punched a hole in the map and ran off in a sprint. Sheesh.

Labels: argentina, chile, lola, maps, patagonia, south america, travel

Working through my backlog of e-mails, I find that I have a few more Rockies course final projects to share with the world:

Laurie's website on Yellowstone geothermal features.

Jared explores Ringing Rocks.

Kevin suggests "more study is needed."

Ken discusses Grinnell Glacier:

Amanda reviews the Tetons:

Labels: glacial landforms, glaciation, montana, mountains, stromatolites, volcano, water resources, wyoming

A quick sketch of a glacial boulder that I showed you two days ago...



Here's what caught my eye:



What else do you see here?

Labels: granite, metamorphism, new york, structure

Yesterday, I asked you, "What is the origin of these red polka-dots on this apparently white sample?"



And I gave you a hint that this cobble was photographed at the "half drumlin bluff" site I detailed the previous day! And the fact that the word "apparently" was in italics was also a hint.

Well, here's the deal -- this is a red cobble, with a white coating. I think Paul said it was the Oswego Formation, a fine-grained reddish sandstone. I think what's going on here is that all the limestone powder in the till is readily dissolving during rain storms, and the dissolved calcite gets carried along in solution, flowing over and around larger clasts like this cobble. Then, as it dries out, it begins to precipitate a coating of calcite all over everything (maybe with entrained clay and silt particles too?). Then along comes a little sprinkle of rain, and individual raindrops splash away this encrusting solution from little circular areas, revealing the red rock beneath. I saw this same phenomenon on several cobble and boulder lithologies, not just the red ones.

What do you think? Plausible?

Howard came pretty close in the comments (though this is the top side of the cobble, not the underside), and as the sole guesser, I reckon that entitles him to the prize. Howard, send me your mailing address if you want a bumper sticker.

Labels: contest, new york, sediment

Bill McKibben on political conservatives and climate change. (Orion) - This addresses what I see as a fundamental contradiction in modern political discourse: the fact that a lot of "conservatives" aren't into conserving natural systems. It bugs me & McKibben both.

Weather vs. climate (Surprising Science, a Smithsonian blog)

The new Wooster Geologists blog, featuring some awesome imagery of the Canadian Rockies.

Some advice about finding the right geology grad program for you (from Christie at the Cape)

Labels: climate change, global warming, politics, websites

The Smithsonian's National Museum of Natural History is looking for a creative individual to work on contract in the capacity of Producer/Writer for a new Human Evolution website. In this capacity, the individual will work with the Museum's Human Evolution Web team, and coordinate with the Web Development Contractor to bring creative solutions to presenting the human evolution story, shaping, editing, and writing multimedia content. We are looking for someone with experience writing science stories, producing multimedia, and developing content for museums. For more information, contact Robert Costello, costellor@si.edu.

Labels: anthropology, evolution, jobs, museums, smithsonian

A quick contest:



What is the origin of these red polka-dots on this apparently white sample?

Hint: this cobble was photographed at the "half drumlin bluff" site I detailed yesterday!

First one to answer correctly is entitled to a free "GEOLOGY ROCKS" bumper sticker!

Labels: contest, new york, sediment

Very cool!

Here's my favorite... Or maybe this one? ...Or potentially this one? No, no: definitely this one.
Actually, this is pretty cool too. Sigh... too many to choose from. Too hard to pick just one fave...

Hat tip to Lee Allison!

Labels: structure, tech, websites

Working through my RSS feed from the past week when I was out of town: Sheesh, it sure builds up if you don't stay on top of it! A couple of notable items to share:

The geography of tapirs, from the Why Evolution Is True blog.

The declining emphasis on literacy in our society, from Alternet.

Women geoscientists who read and/or write blogs: complete this survey!, from Kim.

Outcropedia, a new web project to catalog and share key outcrops.

Climate change graph jam, from Tamino. (With follow-ups from Lockwood)

Skeptics & athiests visit the Creation Museum. (ABC News)

Labels: blogs, evolution, graphics, humor, maps, politics, websites

Labels: glacial landforms, glaciation, new york, sediment, travel

Yesterday, I asked you to see what you see here:


And today, I shall tell you what I saw...

Here's what it reminds me of:

...An Olenellid trilobite (slightly deformed)!

Here, I'll sketch it for you:


Garry Hayes came closest to my vision by suggesting the foam pattern resembled Marella splendens, Walcott's "lace crab" of the Burgess Shale.

Labels: art, arthropods, contest, fossils, structure

Tthe deadline for submission of applications for the GSA's Subaru Minority Student Scholarship is 15 August 2009. At the present time they have very few applications for this $1,000.00 scholarship to an undergraduate student, so they are contacting campus representatives like me to encourage submissions. Details about the scholarship and the application.

Labels: scholarships

Last week, I visited the Taconian Unconformity in the Catskills region of New York. I found out about the outcrop via the informative website the USGS put together in 2003 to explain southeastern New York's varied and interesting geology (Click here for a map).

Here's me at the angular unconformity, demonstrating the layering with my forearms:


Here's the same outcrop, sans goofball, avec annotations:


This is a classic angular unconformity. It even graced the cover of the (excellent) GSA publication Excursions in Geology and History: Field Trips in the Middle Atlantic States (Frank Pazzaglia, editor; cover photo by Marli Miller). Why should we care? Because like the "original" angular unconformity at Siccar Point in Scotland (described by James Hutton), this outcrop represents a lot of geologic time. First, during the Ordovician period, the Austin Glen formation had to be deposited as layers of clastic sediment in an ocean basin. Then, during the late Ordovician Taconian Orogeny, those layers had to be deformed: folded and buckled so they stood up on end, and then eroded down to their nubs. Then, on that newly-formed erosional surface, a fresh layer of sediment had to be laid down, in this case, the Rondout Formation was deposited as a layer of carbonate mud during the late Silurian period. Then, that too was deformed, during the Devonian period's Acadian Orogeny. Finally, the whole package had to be uplifted to the surface and exposed (in this case, when a highway roadcut was completed). That's a lot of time!

I'm delighted to have had the opportunity to visit it first-hand!

Labels: devonian, maps, mountains, new york, ordovician, silurian, structure, travel, unconformities

Just back to DC after a lovely week up in upstate New York, enjoying the scenery, hiking, and geology. Here's a little treat for you: a foam pattern on a stream, en route to Big Slide Mountain in the Adirondacks. What does it look like to you?


...I'll tell you what it looks like to me, tomorrow...

Labels: contest, new york

New Paltz, New York (a big climbing town).

Labels: humor, new york

I made it to Lake Placid. It's raining buckets here.

Labels: mountains, new york

Good morning! I'm in New Paltz, New York, right now, on my way up to the Adirondacks for several days of fun, to be followed by a visit to a geologist pal in Drumlin Land, and then a quick excursion to visit some other friends in Canada. Later this morning I'll visit the Taconic angular unconformity outside of Catskill, New York. I'll try and post photos and whatnot as I go, in the same manner as yesterday's ptygmatic fold post -- my first ever remote post from the new iPhone. But I forgot to bring the iPhone charger, so we'll see how I do... Anyhow, stay tuned.

Labels: canada, mountains, new york, tech, travel, unconformities

Here's a nice fold I saw the other day at the Smithsonian:

Labels: museums, smithsonian, structure