A shot from DC's Tidal Basin this weekend:

Labels: birdies, dc, plants

The Berkeley Seismological Laboratory (which initiated an RSS feed a few months back -- well worth subscribing to) has a post up today showing the seismic signals generated by last weekend's Yosemite rockfall. Check it out!

Labels: blogs, earthquakes, mass wasting

On Wednesday, April 1, the U.S. Geological Survey will kick off a new public lecture series at their national headquarters facility in Reston, Virginia.

The USGS "Science in Action" public lecture series will be held the first Wednesday of every month. These evening events are free to the public and intended for a general audience to familiarize them with science issues that are meaningful to our daily lives. The USGS speakers are selected for their ability and enthusiasm to share their expertise with an audience that may be unfamiliar with the topic.

The first one: From 7-8pm, Dr. John Jones, an expert in remote sensing, will discuss several projects in the Shenandoah National Park and the Everglades. Learn how science from satellites can help decision-makers address issues related to climate change, water resources, and habitat conditions.

Upcoming lectures will be about climate change, hurricanes, energy, glaciers, and a fascinating expedition down the Congo River.

Lectures are held at the USGS building located at 12201 Sunrise Valley Dr., Reston, Va.
For more information on the next three talks - speakers and abstracts - visit the USGS Public Lecture Web site or call 703-648-4748.

Hat tip to Dave Schumaker's Geology News blog.

Labels: meetings, virginia

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

Passing on some excitement:

For the filming of a TV pilot, there will be a simulated explosion on Wednesday, March 25 between 9:30 a.m. (tomorrow morning) and noon near Key Bridge in the District.

The explosion will produce a 20 to 30' fireball that will last for approximately 2 minutes.

Please pass along this information to others appropriate. The Department of Homeland Security and D.C. Police and Fire departments have been notified, along with the Washington Airports Authority. The Virginia State Patrol and Arlington Police Department will be contacted. If you have additional questions, contact Kathy Hollinger or Burt Warner with the DC Film Office at 202-727-6608.

The explosion will take place on the Potomac River just north of the Key Bridge and Jack's Boathouse (K / Water Street, NW under the Whitehurst Freeway). In the scene to be filmed, there will be six (6) sculling boats on the Potomac River and one of them blows up. CBS Paramount television is filming a pilot titled "Washington Field." This is a new television series about the elite Washington field office of the FBI and a team of agents with exceptional and diverse skills who are called together for only the most critical cases.

Labels: action, dc, news

The backlog of photos from my hikes several weeks ago still looms. I've showed you exotic cobbles, migmatites, graded beds, flood debris, and boudins, now for some folds...

As with the others, these are images from the Maryland Piedmont, along the Billy Goat Trail in C&O Canal National Historical Park.

Here's two repeats that fall, Venn-diagram-like, into the overlap area between the "graded beds" theme and the "folds" theme:




Now for some fresh, never-before-seen images:







(that's a fold cut twice oblique to its axis, resulting in an elliptical outcrop pattern).

Tiny folds:


Folds in one direction (top to bottom); boudinage in the perpendicular direction (left to right):


Found this one on the side of a cliff I probably should not have been scaling:


That's all for now... have a good Tuesday!

Labels: igneous, maryland, metamorphism, national parks, piedmont, primary structures, structure

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

Heh! This "clean coal" debunking campaign is directed by the Coen Brothers.

And another:

Behind the scenes:

Labels: climate change, CO2, coal, global warming, humor, politics

I'm returning now to the slew of new images I shot a couple of weekends ago on the Billy Goat Trail (BGT). Previous posts from these back-to-back morning hikes here, here, here, and here.

Today's theme: boudinage, the stretching & breaking of more competent rock units, and the gaps in between the 'chunks' filled in with less competent (more 'flowy') rock units, or by magma or other fluids. It's a behavior that's neither purely brittle nor purely ductile, but somewhere in between.

Boudinage of granite in metagreywacke:


Ditto (although some of this looks closer to hydrothermal quartz than granite, but there is some K-spar present...):


Felsite boudins in amphibolitic gneiss:


Pretty cool here; you can see that fluid magma filled in the gaps between the boudins. When this boudinage happened, the surrounding amphibolite was too viscous to flow into the gap. Furthermore, the asymmetry of these granite-filled tension gashes indicates some shearing: Was it a sense of shear that was concurrent with the boudinage (top to the left)? That was my initial take, but Kim (in the comments) suggested an alternative, which I like more and more: initial boudinage, and then later shearing in the opposite direction (top to the right). See the discussion in the comments section for more insight...



Some of the weirdest rocks on the Billy Goat Trail are these ones near Trail Marker 2. They are coarsely layered by composition, but I'm not able to figure out quite what the heck is going on with them. Is it just a gneiss with compositional banding ~3 inches thick? Regardless, it shows boudinage, both in horizontal cross-section...



...and in vertical cross-section:


When a rock gets boudinaged in two directions, it records flattening strain perpendicular to the plane of foliation, and goes by the colorful moniker "chocolate table boudinage." (Think of a Hershey bar's grid-like segments. If you smashed your hand down on it, the square chunks would separate from another and move apart, perpendicular to the direction in which you're pressing on it.)


Here's a quartz vein (cross-cutting metagreywacke) that's been boudinaged:



Part of this vein is milky quartz (on the left: white & easy-to-see), but part is transparent quartz (looks kind of grey in outcrop; difficult to see against a grey host rock), so I've used the wonders of Photoshop to turn that portion white, too, in this modified image:



Here's a new boudin that I never had seen before, on a diversion trail off the main C&O Canal towpath due to a breach in the Canal after Tropical Storm Hanna last year:


Lastly, here's something new (to me) that I found on my hike. It's a gigantic boudin of amphibolite in the foliated felsic rock showing chocolate-tablet boudinage that I showed up above. Unadulterated photo:


...And with annotations:


This is a big, angular block of amphibolite (about 1.5 m across) that has the foliation of the "gneiss" wrapping around it. Along strike of the foliation, there are two big rusty square holes, where I interpret other big boudins of amphibolite have weathered out. (As I showed the other day, the granite stands up signficantly better to weathering than does the amphibolite.) I was somewhat astonished to recognize this as a big boudin: it has very crisp edges, and is huge in comparison to other boudins that I am familiar with. Neat-O! I'm going to take my structural geology students here in a couple of weeks and have them examine and interpret these structures.

Labels: geology, igneous, metamorphism, piedmont, structure

One of my students, Rob M., forwarded this photo to me over the weekend:



He tells me his dad took it along the coast of Alaska. Pretty cool shot. Unlike most of the photos on this blog, you can click through to get a big version.

Thanks to Rob and his dad for permission to share the photo here!

Labels: alaska, glacial landforms, glaciation

Audio (and video) to share the sound of springtime froggies calling, along the Berma Road trail in C&O Canal National Historical Park:

Labels: amphibians, maryland

An article in today's Kids' Post discusses rock collections.

Hat tip to Brian R!

Labels: dc, minerals, teaching, virginia

Labels: maryland, structure

The Association of Environmental and Engineering Geologists is having NOVA adjunct geology instructor Steve Stokowski talk at their meeting on Thursday. His topic blends petrology (the study of rocks) with applied science.

Sexy Pictures, Busted Bridges, Broken Buildings, and Messed-Up Monuments: A Petrographic Odyssey

Microscopic analyses and geologic understanding are essential for the correct diagnosis and corrective actions necessary when rock, brick, concrete and similar building materials deteriorate, as these four case histories illustrate. The first case history is of the deteriorated brownstone loggia at the Oakes Ames Memorial Hall, North Easton, MA. The second case history is of a total replacement failure of a large memorial to WWII veterans in the Rhode Island Veterans Cemetery, Exeter, RI. The third case history concerns the use of defective, cracked, and residually expansive brick to construct the Prospect Mountain High School, Alton, New Hampshire. The final case history concerns deterioration of the 1930's Fore River Bridge between Quincy and Weymouth, Massachusetts. It can be expensive to correct the effects of the deterioration of common building materials!

Pulcinella's Restaurant
6852 Old Dominion Drive
McLean, VA 22101

AEG members, guests $30.00
Students $10.00

6 p.m. to 7 p.m. Social Hour and Section Business
7 p.m. to 8 p.m. Dinner
8 p.m. Presentation
9 p.m. Closing Statements

Labels: geology, meetings, minerals, science and society

I've gotten hooked on watching these TED talks. You should too.

Here's Peter Ward talking about mass extinctions. I like this because I saw Ward give a similar talk at NSF once, and meant to blog about it, but got distracted by a thousand other things, and now here it is, a year later, and I can finally showcase this talented scientist discussing his specialty:

It gets a little fringey towards the end with talk about battle wounds and preserving people, but I like scientists like Ward who think outside the box and connect up different perpectives and different fields of inquiry. Enjoy!

Labels: evolution, fossils

GSW Spring Field Trip: Sunday, May 17, 2009

The Potomac Gorge: An Extraordinary Meeting Place of Geological and Biological Diversity

Led by: Tony Fleming, Natural Areas Geologist, and Gary Fleming, Vegetation Ecologist, Virginia Department of Conservation and Recreation

The Potomac Gorge between Great Falls and Georgetown is recognized as one of the most biologically diverse sites in the eastern United States, with an unusually large concentration of rare flora, fauna, and natural communities. For more than a century, the gorge has also enjoyed an iconic reputation as the region's premier geological area, both for its exceptional exposures of Piedmont bedrock and the complex tectonic history they reveal, and for the natural fluvial cycle of flood disturbance that still operates on the Potomac, the only Fall Zone river of its size whose flow is not altered by dams. Geology and ecology converge on this field trip, as we visit two sites where geologic processes exert a powerful influence on the distribution of unusual natural communities. At Turkey Run Park, we will hike past steep boulderfield communities and regionally rare sugar maple/mixed mesophytic forests more typical of New England, here growing on soils weathered from basic intrusive rocks in a cool microclimate created by processes driven by Pleistocene glaciation and the ongoing southward migration of the Potomac Valley. Chain Bridge Flats, by contrast, is a unique flood-scoured bedrock terrace hundreds of hectares in size that displays a complete ecotone of communities adapted to progressive changes in the form and intensity of natural flood disturbance as one approaches the river. Among these are disjunct, prairie grasslands containing calcium-loving plants more typical of the Midwest and Great Lakes. This site also is the largest and cleanest exposure anywhere in the Piedmont of the Sykesville Formation, the enigmatic and often inscrutable submarine trench deposit from the Taconic subduction zone that makes up much of the local bedrock. Here, a phenomenal array of textures, exotic inclusions, mega stratification, volcanic detritus, and metamorphic features can be seen together at a clarity and scale unlike anywhere else, providing insights into the origin of this enormous sedimentary melange.

Key Topics: Ecogeology; Georgetown Intrusive Suite; Sykesville Formation; Pleistocene and Holocene history of the Potomac Gorge; weathering, ground water, and nutrient cycling; flood frequency and dynamics

Field Trip Details: Hike departs promptly at 9:30 AM from lot C-1 at Turkey Run Park, and will follow the Potomac Heritage Trail towards Dead Run, returning to the parking lot by around noon. Eat lunch at the picnic area overlooking the old soapstone quarry at Turkey Run, before driving across the river to Chain Bridge Flats. Afternoon hike will depart around 1:30 from the parking area on Clara Barton Parkway immediately north of Chain Bridge, and will follow the towpath and ACE spillway out to the flats. Return by 4 PM. Expect spring wildflowers, poison ivy, some steep grades at Turkey Run, and rough terrain involving scrambling on rocks at Chain Bridge Flats. Sturdy footwear is a must. Bring lunch, snacks, and water. Restrooms are available at Turkey Run Park, but not at Chain Bridge Flats.

Questions? Contact Bill Burton at bburton@usgs.gov

Labels: field trips, gsw, piedmont, plants, rivers

Picking up where I left off last week with cool new pictures of rocks from the Billy Goat Trail, today we examine igneous beasties...

As you may have picked up from previous posts on this blog [e.g. here], the rocks of the Piedmont province are essentially the mangled remains of an ancient ocean basin: deep sea sediments, oceanic crust, volcanic islands, even microcontinents -- and all were crushed between North America and Africa during the mountain-building that closed the Iapetus Ocean and formed the supercontinent Pangea. Along the Billy Goat Trail, Piedmont rocks are exposed that started off as deposits of mud and dirty sand, but then were metamorphosed during mountain-building. From the bottom of the ocean to the center of a mountain belt: that forces rocks to change. In some places, they heated up so much that they began to melt.

When rock partially melts, but then the melt crystallizes in places (i.e., it doesn't completely drain out of the source rock), we call it a migmatite. The Billy Goat Trail has some spectacular exposures of migmatite. Here's three shots from the downstream end of the trail:







If migmatitic rock rips open while it is in this partially-molten state, that generates cavitites that the fluid magma flows into and fills. Here, for instance, you can see a rip in the foliated migmatitic metagraywacke that is filled with granite.


Further away from the source rock, mobilized magma can fill in planar fractures that cut across older rocks of many varieties. These cracks are filled in with magma that cools into igneous rocks, and we call them dikes. Here is a new dike I discovered on my hike last week: a vertical dike of granite about one foot thick, cutting across non-migmatitic metagraywacke:


Here's a granite dike cutting amphibolite; weathered out in high relief:


Same dike, from a slightly different angle (I leaned over to the left), to show how it pokes up above the amphibolite like a little wall:


Metamorphosed (some epidote present) granite dike cutting amphibolite:


These fractures didn't open up wide enough to admit large volumes of fluid (either magma or hydrothermal solutions), but there was some fluid flow along them. How do we know? The rock immediately adjacent to each crack weathers out in high relief, suggesting a higher proportion of stable, tough minerals (like quartz). [We've seen this before.] The base rock here is fine grained amphibolite.


Contact between a small granite pluton (or a large dike?) and neighboring amphibolite:


Tension gash in amphibolite, filled in with a mix of potassium feldspar and quartz:


Xenoliths of foliated biotite-rich rocks which I interpret to be metagraywacke that has had all its felsic melt expressed from it, then ripped off by the growing granitic magma chamber (stoping) and dropped into the magma (relatively low temperature, so the biotite doesn't melt), and rotating around to new orientations which do not match the regional foliation orientation. I'm seeing these as shreds of the 'depleted' migmatitic source rock...


Closer-up of these xenoliths #1:


Closer-up of these xenoliths #2:


Another cool thing I saw on last weekend's hikes was pegmatite. Pegmatites are present where there is a particularly watery magma. Water, the universal solvent, helps act as a courier, ferrying atoms around to where growing crystals can access them and add to their bulk. As a result, pegmatites are characterized by really large crystals. These potassium feldspars are highlighted by lichens which grow at the interface between the feldspars and the surrounding milky quartz:


Those same black-colored lichens can also highlight the cleavage planes of the feldspars:


Another big-ass K-spar:


...and another:


I love this stuff. Hope you enjoy these igneous treats as I much as I enjoy sharing them.

Labels: igneous, maryland, metamorphism, piedmont

I hereby initiate a geoblogosphere meme...

What are ten things that every geology major ought to know about? The only restriction is you're not allowed to list anything that has already been listed by a previous geoblogger. You don't have to list everything, just ten important things.

My ten:

1. The relationship between cooling rate and crystal size in igneous rocks.
2. The fact that rocks can flow, given sufficient temperature and pressure [and low strain rate, for the purists out there].
3. The idea that sedimentary rocks reflect specific depositional settings. By studying modern depositional settings and the sediments they contain, we can interpret ancient sedimentary rocks in light of the conditions under which they accumulated.
4. The fact that the chemical stability of molecular configurations (minerals) changes with different temperatures and pressures (metamorphism).
5. Large Igneous Provinces, and their potential role in tectonics and expressing mantle plumes.
6. Elastic rebound theory for the origin of earthquakes.
7. The notion of partial melting, and its relationship to Bowen's Reaction Series.
8. An understanding of the carbon cycle, and an understanding of the atmospheric physics that facilitate global warming.
9. The role that rivers play in shaping the landscape: nickpoints, terraces, quarrying, abrasion, drilling of potholes, etc.
10. The Earth is 4.6 billion years old, which is extremely old in comparison to human life -- and the reasons we think it's so old [Pb isotopes, etc.].

Please, add to these... So far Mel at Ripples in Sand, Chris at GoodSchist, Eric at The Dynamic Earth , Lockwood at Outside the Interzone, Bryan at In Terra Veritas, Kim at All My Faults..., Garry at Geotripper, and the Short Geologist at Accidental Remediation have added their top tens. Plus, Silver Fox at Looking For Detachment posted 4, and the comments section on this post has another suggestion from Michael Welland (of Through the Sandglass) and others. That's 85 things to know... and counting...

Labels: blogs, geology, 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

The March meeting of the Potomac Geophysical Society will be held March 19th at the Fort Myer Officers' Club in Arlington, VA in the Campaign Room. This month's talk will be: Geoarchaeology, Hydrology, and Wetland Morphology in the Belize Coastal Plain, by Sheryl Luzzadder-Beach (Assoc. Prof., George Mason University) and Timothy Beach (Professor, Georgetown University). Reception at 6:30. Dinner at 7:30. Talk at 8:30 PM.

Labels: belize, central america, pgs

Geological Society of Washington: Meeting 1432
Wednesday March 25, 2009

• Andrew Todd, US Geological Survey, Denver, Colorado - Abandoned Mines and Trout: The Interaction of Geochemistry, Metal Bioavailability, and Stream Ecology.
  
• Ian G. Macintyre, Smithsonian Institution, Washington, DC - The Almost Total Loss of Acropora palmata from Shallow Waters off Barbados, West Indies, Initiated by Catastrophic Destruction of a Major Bank-Barrier Reef off the Southeast Coast.
  
• Thomas J. Casadevall, U.S. Geological Survey, Denver, Colorado - Lusi: Long-lived Mud Eruption near Surabaya, Indonesia.

John Wesley Powell Auditorium, Cosmos Club
2170 Florida Ave NW
Washington, D.C.

Refreshments 7:30 pm; Meeting 8:00

Future meetings 2009: April 22 (Bradley Lecture); Sept. 23; Oct. 14; Nov. 4; Dec. 9.

Labels: environmental, fish, gsw, meetings, mining, reefs, volcano

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

What's going on here?


(Michelle Arsenault of NSF for scale)







First person to answer correctly wins a "GEOLOGY ROCKS" bumper sticker!

Labels: contest, plants

Check out these amazing structural photographs, available in high resolution too!

Labels: england, northern ireland, republic of ireland, scotland, structure

I'm sure I won't be the only one to be writing about this today, but here's a couple of links to news items about Liberty University's "Advanced Creation Studies" students touring the Smithsonian Institution's National Museum of Natural History.

NBC (snarky!)
Washington Post (with photos)

Labels: evolution, museums, news, smithsonian, teaching

I mentioned seeing some cool stuff when I went hiking on the Billy Goat Trail last weekend.

One of the things that really caught my eye were multiple new exposures of graded bedding. These rocks began as deposits of sediment offshore from a volcanic island arc: they consist of turbidite deposits that were then squished and squeezed as that volcanic island arc collided with eastern North America during the closure of the Iapetus Ocean. As a result of this, they were metamorphosed and deformed. But in a few places, you can still see the relict graded beds that originated through the settling out of turbidity currents.

Here's some images:

I count four or five here:





A nice central fault zone displaced the central block downward:




This one is a little more subtle...


Here's one that's been turned upside down (by tectonics):


And there were also some folded examples:




A close-up of the hinge of this folded graded bed:


Pretty cool, eh? The only problem is these samples aren't on the Billy Goat Trail itself, which means I'll really never be able to show them to students except in photographs...

Labels: geology, maryland, metamorphism, national parks, piedmont, primary structures, sediment, structure

Sorry for the late notice... this is for today at lunchtime.



Abstract: The Silver Hill Mine in Davidson County, North Carolina was the first important underground silver mine in America. Discovered in 1838, it produced significant quantities of silver and lead into the mid-1840's. As the oxidized ores were depleted, abundant, rich, lead-zinc sulfide ores were encountered. These complex primary ores presented the mine operators with difficult metallurgical problems. Mine development and production slowed. Nearly a decade passed as the owners experimented with new processing and smelting technologies. These efforts were largely unsuccessful and the mine closed in the early 1850's. The Civil War created an urgent need for lead to supply Southern troops. The Confederate government operated the Silver Hill Mine to provide an alternate source of lead in case the mines at Austinville, Virginia should fall into Northern hands. Lead concentrates with high silver values were shipped from Silver Hill to the newly constructed Confederate smelter in Petersburg, Virginia. After the War, the mine continued to operate for several years but the problems of the refractory sulfide ores were not solved and the mine closed again. For more than a century after production stopped, the Silver Hill Mine was the repeated target of both mining companies and stock promoters.

Where: Pier 7 Restaurant, 650 Water Street, SW, Washington, DC (within walking distance of the Waterfront Metro on the Green Line) Free parking with validation from Pier 7 Restaurant.

11:30 - Social 12:00 - Lunch 12:30 - Speaker

Meeting cost: $20.00 for Washington, DC Section SME members $25.00 for non-members

Contact Steve Stokowski with questions

Labels: dc, history, meetings, minerals, mining, north carolina

Ladies and gentlemen, spring has arrived in the Washington, DC region. It is sublime. I'm very grateful that it's my spring break this week because even though I still have a ton of work to do, I've had the opportunity to get outside every day and enjoy a bit of the weather.

This weekend, I got up early both days and headed out the the Billy Goat Trail, a rugged hiking trail along the Potomac River's gorge about 12 miles upstream from DC. I departed from the trail itself both days, which was great because it brought me to places I hadn't seen before. I found a lot of cool new structures and rocks! Over the next few days or weeks, I'll be sharing some of those images with you, but for today, I figured I'd show you some 'soft' imagery, just to celebrate the fun of being outside on a hike on a lovely day. ...and wearing short sleeves, no less!

Here's a shot of typical scenery along the Billy Goat Trail. This is looking upstream:



One of my side-trips off the trail... because the water level was pretty low, I was able to get to some islands that are often inaccessible. This is the channel between the Rocky Islands (downstream of Great Falls, upstream of Mather Gorge):



This land is all part of the C&O Canal National Historical Park. Here's a spot where rains from Tropical Storm Hanna breached the wall of the C&O Canal, allowing its water to drain downward into the Potomac. Because the canal's towpath was located there, the Park Service has constructed a temporary path which detours around the breach:



I saw some good birds on my hikes there. Red-tailed hawks, double-crested cormorants, Canada geese, mallards, belted kingfishers, pileated woodpeckers, red-bellied woodpeckers, tufted titmice, chickadees, robins, blue jays, and great blue herons. Also, both local species of vultures: the turkey vulture and the black vulture. This is a black vulture (note the black, not red, head):



Here's some tracks: theropod dinosaurs? ...or great blue heron? You be the judge:



Here's a cool fish skull I found:



Of course, it wasn't all scenery, birds, and fish. There were rocks, too. I took a lot of rock photos, and you'll get to see them all in due course... But for now, let me start you off with the tame stuff. Here's some cobbles I encountered along the hike...

Cobble of the Seneca Sandstone (Triassic arkose) showing a mudchip rip-up clast:



Tilting it a bit, you can see other mudchips too:



Cobble of cement containing Seneca chunks:



Cobbles of quartzite of the Antietam Formation showing Skolithos 'worm' tube trace fossils:



I love these Skolithos tubes. It's hard not to love them, and they're everywhere around here. Like the Seneca cobbles, they come from source areas to the west (Culpeper Basin & Blue Ridge, respectively), and were transported to the Maryland Piedmont by the ancestral Potomac River.



My favorite Skolithos-bearing quartzite cobble:



...And the same cobble, end-on:



More to come, tomorrow...

Labels: birdies, blue ridge, culpeper basin, fish, fossils, maryland, national parks, piedmont, sediment

This was forwarded to me today; I'm posting it as a "public service announcement" for local cavers:


Prepared by the Virginia Department of Conservation and Recreation (DCR) Natural Heritage Program in consultation with members of the caving community and staff from the Virginia Department of Game and Inland Fisheries (DGIF). This statement is supported by the Virginia Cave Board, the Virginia Speleological Survey, the Cave Conservancy of the Virginias, the Board of the Virginia Region of the National Speleological Society, and the Butler Cave Conservation Society.

White Nose Syndrome (WNS) is a condition that has resulted in the deaths of hundreds-of-thousands of bats in the northeastern United States since 2006. It is associated with a Geomyces sp. fungus that grows at cold temperatures and colonizes the skin of animals in cold environments. This is consistent with properties predicted for a causative agent of WNS-associated cutaneous infection. More on WNS can found here.

This winter cases of White Nose Syndrome (WNS) have been confirmed in Pendleton County, West Virginia. In February, surveys of significant bat and recreational caves in adjacent Highland and Bath counties in Virginia discovered what appears to be WNS in Breathing Cave in Bath County, located near the Highland County border. On March 3 in response to caver reports of dead bats, a survey of Clover Hollow Cave in Giles County identified a second apparent WNS outbreak. Specimens from both sites have been sent to USGS National Wildlife Health Center in Madison, Wisconsin for analysis.

This winter, 18 Virginia caves in Giles, Bland, Page, Wise, Lee, Bath, and Highland counties have been surveyed for WNS. So far, signs of WNS have only been observed in Bath and Giles counties. However, since Highland County lies directly between Bath County and Pendleton County, West Virginia, along the same belt of karst, it is likely that WNS is present there as well. There is mounting evidence that humans may play a significant role in transmitting biological agent(s) responsible for WNS in bats. The strongest such evidence is that WNS is showing up first in the Virginias in recreational caves with high visitation. It is known that some of those cavers visiting the affected West Virginia Caves had previously visited WNS affected caves in New York. While it is unlikely that humans are the sole or even the primary vector, transmission of the disease by humans may increase both the rate of expansion and geographic extent of WNS.

The Virginia Cave Board and Natural Heritage Karst Program are asking for a moratorium (a voluntary ban) on all underground caving activity in Virginia until April 15, 2009. A new statement will be issued on or before that time. Please note that at that time, we may ask to further extend the moratorium. During the moratorium, three tasks will be accomplished.

1. Scientists from DGIF and DCR will work to identify significant bat caves to which access will be limited in an attempt to slow the spread of WNS by humans. A significant bat cave is defined as a cave used by rare or endangered bat species, significant numbers of common bat species, and/or a high diversity of bat species. Input from cavers is sought and encouraged. A list of these caves will be posted on the VAR List of Closed and Limited Access Caves. Please note that many of the significant bat caves are already gated, closed, and/or have limited (seasonal) access.

2. Additional caves will be visited by biologists to better assess the current extent of WNS in Virginia. We will work to temporarily restrict access to caves in which WNS is present.

3. DGIF and DCR scientists will work with other biologists studying WNS to establish and refine protocols to reduce the possibility of transmission of WNS by cavers. The two major protocols under consideration are listed below. Comment on these protocols is welcome, especially during the moratorium period. Cavers choosing not to observe the moratorium are strongly urged to follow these draft protocols. Once the moratorium is lifted, all cavers will be asked to follow protocols to reduce the risk of transmission of WNS.

Draft protocols to reduce transmission of WNS in Virginia by humans

1. Geographic isolation of caving activity and/or gear: Cavers are requested to limit their caving activity to one caving area as defined by a county or group of counties. The designation of caving areas appears at the end of this document. We are asking this because sterilization procedures are likely not 100% effective, especially since neither the specific causal agent nor mode of transmission has yet been definitively identified. Cavers choosing to cave in more than one of the defined caving areas are asked to dedicate a specific set of clothing and caving gear for each respective caving area. If you must go caving in multiple areas, complete disinfection of vehicles is recommended between trips to different areas. Special care should be taken to segregate any cave clothing and equipment dedicated for use in a given area from all other sets of clothing and equipment dedicated for use in other caving areas.

2. Strict adherence to decontamination procedures when moving between caves (even within the same geographically designated area). After exiting one cave and prior to entering another cave, even within a designated caving area, decontamination practices as outlined by the U.S. Fish and Wildlife Service must be strictly adhered to. ALL equipment must be cleaned! These procedures are posted online here. To reduce the risk of harboring or carrying the disease on their persons, cavers should thoroughly clean and scrub themselves with soap and hot water following each trip to each cave. All clothes worn while traveling to and from the caving area should be laundered as soon as possible following caving trips.

List of Virginia Caving Areas
Alleghany Highlands: Alleghany, Bath and Highland counties
Shenandoah Valley: Frederick, Clarke, Warren, Shenandoah, Rockingham, Augusta, and Page counties
Middle James and Roanoke River basins: Botetourt, Rockbridge, Roanoke, Craig (except RT 42 south of Newcastle) counties
New River North: Giles, Montgomery, and Craig counties (only RT 42 south of Newcastle)
New River South: Bland, Pulaski, and Wythe counties
*Holston: Smyth and Washington counties
*Clinch: Scott, Russell, and Tazewell counties
*Powell: Lee and Wise counties
_________________________________________________________________________________
* - These areas are in the upper Tennessee River basin, and include the northeastern boundary of the range of the Gray Bat (Myotis grisescens). This species is not yet affected by WNS. If you are caving in these areas, please only cave in these areas. If you are not caving in these areas, please do not start.

Labels: caves, disease, mammals, virginia, west virginia

Heh heh.

Labels: earthquakes, humor

The National Academies' Ocean Studies Board would like to announce that Dr. Paul G. Falkowski, Board of Governors' Professor at Rutgers University, will be the speaker for the tenth annual Roger Revelle Commemorative Lecture, scheduled for Tuesday, March 17, 2009 at 5:30pm. It will be held in the Baird Auditorium in the Smithsonian's National Museum of Natural History (10th Street and Constitution Avenue). Dr. Falkowski's talk is entitled:


The ocean has been a feature of Earth's surface for at least 4 of the past 4.5 billion years, and has provided the primary environment for the evolution of microbes that drive the biogeochemical cycles on Earth. Over this long period of time, the ocean has witnessed extreme changes, ranging from complete coverage with ice to extensive periods when there was no ice at all; periods of extraordinary extinction of animal life, to periods of dramatic evolutionary radiation of animals. Throughout all of Earth's history, the ocean has served as the primary backbone of life on the planet; and the core metabolic processes have been successfully transferred across vast stretches of geological time. Humans, in contrast, evolved only about 200,000 years ago, and in that short period of time have come to successfully outcompete and plunder many of Earth's living resources. Over the past 100 years, in particular, we have increasingly altered the trophic structure of the ocean as well as its physical circulation and chemical properties. While human impacts will surely alter ecosystem functions the core metabolism of the ocean will go on. Rather, ironically, humans are the fragile species that will lose capabilities of using the ocean as a source of food and novel molecules. Our future is intimately tied to that of the ocean. We have to begin viewing the oceans as a key component of the Earth system; one that we cannot live without.

This event is free and open to the public. For planning purposes, please complete this brief registration form. You are encouraged to post the event flyer or to forward it to your colleagues. For more information, contact Pamela Lewis.

Please visit Roger Revelle Lecture Series for information on Roger Revelle and on previous lectures.

Labels: dc, meetings, oceans, smithsonian

The Geological Society of Washington now has a Wikipedia page, thanks to society historian Jeff Grossman (USGS). Check it out; add to it.

Labels: gsw, websites

Nevada's Yucca Mountain site for a proposed nuclear waste repository has lost much of its funding in President Obama's proposed budget. Personally, I think this is a good call - I never thought that the Yucca Mountain site seemed viable for the geological long-term. For a facility being designed to outlast human civilization (warning signs are not written in English, but in sign language that's predicted to still be useful when potential meddlers show up 10,000 years from now), Yucca Mountain is located in too tectonically-active an area for my liking. Basin and Range extension, with associated earthquakes and volcanism, imperils the facility's security over the long-term.

But then where do we put this nuclear waste? We've got more and more of it every day. I'm a fan of nuclear energy because I feel that in spite of the risks associated with radioactive leaks, it's a proven technology that looks better all the time because it produces no carbon emissions. To me, the relatively short-term (local) risk of radiation leaks is outweighed by CO2's long-term (global) risk of climate change. Provided sufficient security, I think it's a great "halfway house" between fossil fuels and 'alternative' energies like solar, wind, and geothermal.

Yucca Mountain has several advantages in terms of its location: it's dry, and it's not in someone's backyard (far from large populations -- though Los Vegas residents might quibble with the definition of "far"). But Nevada's regular seismic shaking (3rd in rank among the U.S. states, after California and Alaska) and the proximity of some young volcanic extrusions make me think it's not so great a spot if you want the waste to stay put. I'm thinking that the best place for nuclear waste would be in the craton, the stable interior of the continent. I'm thinking: Canadian Shield, maybe in Minnesota or Michigan or Wisconsin. The issue there is water: you would be trading tectonic stability for saturation and precipitation.

I'll readily admit I'm not an expert here -- just a geologist speculating on an issue that's more complex than mere geology. What do you think? Where's the best place to store nuclear waste until radioactive decay makes it reasonably safe? Use 10,000 years as your hypothetical timeline, bearing in mind how different the world is today than it was 10,000 years ago.

Labels: CO2, earthquakes, energy, environmental, michigan, minnesota, nevada, volcano, wisconsin

The Commonwealth of Virginia has put up a website soliciting suggestions for the expenditure of the state's share of the federal stimulus package. Got a good idea? Drop them a note.

(The Washington Post reports on a decaying bridge in Arlington County as a good candidate - I drove under this bridge on Tuesday morning. Thursday morning at 4am, softball-sized chunks of concrete fell off the bottom onto Route 50. Yikes.)

Labels: economics, politics, virginia

Lichens are symbiotic associations between fungi and algae. The fungus provides the alga with a place to live, and the alga photosynthesizes and shares some of the resulting 'food' with the fungus. One provides room; the other provides board. It benefits both species to hang out together, and provides a nice example of two phylogenetic 'branches' of the 'tree of life' merging into one. There are many varieties of lichens, living in a diversity of habitats, but they're easiest to spot in colder zones where they are first in line to colonize raw rock surfaces.

When I was in Ecuador in January, I saw a lot of lichens, and took some photos of them. I'm not a lichen expert, and I won't attempt to name these varieties. I'm more interested in them as aesthetic phenomena. I find them beautiful.

This one reminds me of ripples on a pond's surface, spreading out over decades and centuries:


The orange here is also a lichen:


These wispy lichens were three-dimensional structures that were found all over the ground surface (not encrusted on a rock) in the paramo ecosystem.


They were present in such profusion in Cotopaxi National Park that the ground looked from a distance as if it had a light layer of snow on it:


Other ground lichens:




Lichen-bearded goofball:

Labels: ecuador, fungi, humor, plants, south america, travel

From NASA's Earth Observatory:

Labels: nova, snow

Labels: granite, metamorphism, piedmont, quartz, structure, virginia

Brilliant! Especially in light of the new fossil evidence about the origins of whales released earlier this year.

From last week's issue of the New Yorker, which I've got time to read today because it's a snow day here in DC!

Labels: art, evolution, fish, fossils, humor, mammals

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