NOVA Geoblog

A gecko you must see

2009-11-20T10:14:00.001-05:00

Mineral show at GMU this weekend

2009-11-20T08:36:00.001-05:00

FYI, locals:
18th Annual NVMC Gem, Mineral & Fossil Show at GMU in Fairfax
November 21 2009 - November 22 2009
Saturday 10:00 AM - 6:00 PM, Sunday 10:00 AM - 4:00 PM

Vintage oil ad oozes irony

2009-11-20T07:21:00.004-05:00

Life magazine, circa 1962. Via Google Books, via Grist, via Cassie W. on Facebook.

Humble Oil later became Exxon, by the way.

Adirondacks, continued

2009-11-20T07:09:00.001-05:00

This image, published earlier this week on NASA's Earth Observatory, reminded me that I haven't finished blogging up my time in the Adirondacks this summer yet:

I'll get back to it soon, I promise.

"The Coral of Life"

2009-11-19T18:01:00.005-05:00

Last night, four Honors students and I (and Lily) went to the meeting of the Paleontological Society of Washington for Richard Bambach's talk on Charles Darwin's geological perspective.

One thing I liked about the talk was the suggestion by Darwin that "The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen." (Notebook B, page 25). This strikes me as quite apt: trees are alive not only at the tips of their branches, but also all along the branches, down to the trunk and the roots. Corals, on the other hand, grow atop a pile of dead material, representing those individuals and species which are in the past. I like it.

PS - While I was Googling up the exact quote, I came across this intriguing looking article about the history of the "tree of life" analogy. Wish I had time to read it...

Pleistocene drainage channels atop the Bishop Tuff

2009-11-19T09:25:00.002-05:00

It's been a while since I last posted about my time in Bishop, California, back in September, when I attended a GSA field forum on the structural and neotectonic evolution of the volcanic tableland.

For reference, here's a list of the previous posts about that trip:
...Faults of the volcanic tableland
...The Bishop Tuff
...The flipping fault

So, picking up where I left off, I thought it would be worth a post to mention the gorgeous drainage channels one sees etched into the top "Ig2" welded layer of the Bishop Tuff. These channels are interpreted as being Pleistocene in age, when the area was wetter than it is now.

Here is a photograph of the most spectacular of these channels, as viewed from the rim:

We visited this vantage on our second day in the field. A hiking path at the bottom of the dry channel imparts a sense of scale.

Here's a Google Map of the area from the perspective of a hawk:

Where the road comes most closely tangential to the canyon is the point where we stopped to take a look at it, and where the above photograph was captured.

Further upstream along the channel, we find it broken by normal faulting. Check out the view across this graben (a graben is a normal-fault-bounded valley, downdropped relative to the highlands next to it). There, you see the distinctive crescent-shaped profile of the drainage channel, but offset along several fault scarps:

There are three scarps on the far side of the graben, and an additional one that Peter is standing on, on this side of the graben. Just behind Peter, you can see a broken relay ramp, too. View is to the northwest; those are the Sierras in the distance.

Here is a Google Map of the area, showing the drainage channel crossing the graben. This conclusively shows that the channel must be older than the faulting which produced the graben.

This Google Map shares its southeastern corner with the northwestern corner of the first one I showed. You can see this for yourself by dragging either one in the appropriate direction. They both share the white-knuckled place where the road goes straight down the fault scarp, rather than sensibly down a relay ramp. That wasn't my favorite thing to drive.

Here's another drainage channel, similarly bone dry, that we visited in our fourth day in the field. Perspective is to the east: those are the White Mountains in the distance:

The Google Map shows a more interesting relationship this time. Instead of the faulting cross-cutting the channel's orientation, this channel approaches the graben to the southeast, curves around (deflecting from its original downhill course) and drops down the relay ramp to the northeast, into the graben (breaking up into multiple channels en route). There, it resumes its original downhill trajectory to the southeast:

This suggests that at least some of these faults were rupturing the "Ig2" layer at the same time that water was flowing over the surface (i.e. before the Owens Valley's climate dried out, post-Pleistocene). The stream's course and the faulting were coeval.

So what was the source of these streams? Did they originate on the volcanic tableland, or were they derived from the Sierra Nevada, prior to incision by the Owens River (which makes a deep canyon a mile or two west of here)? Fred Phillips, of New Mexico Tech, holds up a piece of evidence:

That is not a rounded cobble of the Bishop Tuff. That's a rounded cobble of granite. While the majority of cobbles in these channels are locally-derived chunks of the Bishop Tuff, there are also clasts which originated elsewhere, beyond the volcanic tableland itself. This suggests a source area with a granitic outcrop. One candidate location is Casa Diablo Mountain, north of the (south-sloping) volcanic tableland. Another possibility is the Sierras, to the west.

Another possibility entirely is that the source of the cobbles could be anywhere, and they were brought to the volcanic tableland not by streams but by paleoindians, who used them as grain-grinding stones in their metates.

Once again, we need instructors

2009-11-18T12:02:00.003-05:00

Next semester, the Annandale campus of NOVA has need for two instructors: one for a section of Physical Geology and a second one for a section of Historical Geology.

Both sections meet (in different rooms) Monday and Wednesday evenings, from 6:30 to 9:20 pm.

Minimum degree requirements: an M.S., with at least 18 graduate credit hours in geology. Remuneration is probably millions of dollars, though I'm not sure about that, and I'm sure that's not why you would want to do it, anyhow. Contact my boss, Dr. Craig Jensen, if you're interested: cjensen@nvcc.edu

Ye NE/SE GSA abstract deadline approacheth

2009-11-18T11:03:00.005-05:00

I'm excited about next March's combined northeastern/southeastern GSA meeting in Baltimore, Maryland. The combination of (1) it being a joint meeting (with hopefully robust attendance) and (2) being reasonably close to NOVA means that this looks like an awesome meeting. The abstract deadline is coming up on December 8, so now is the time to act if you want to share some insights at the meeting. I'm going to submit an abstract called "State of the Geoblogosphere," to share the results of Lutz Geissler and Robert Huber's recent geoblog survey. (I had originally intended to do this at AGU, but I can't make the travel to AGU work out with some more important priorities, so it's going to be NE/SE GSA, instead.)

I should also note that I'm eagerly anticipating the post-meeting field trip called "A Traverse of Proterozoic to Paleozoic Laurentia, Virginia Blue Ridge and Valley and Ridge."

Here's the list of sessions and symposia as they stand now (note that they just added one about last week's storm that flooded many low-lying coastal regions of the mid-Atlantic states):

A. It All Starts in the Field: In Honor of Wallace A. Bothner. Jo Laird, University of New Hampshire; Steven Whitmeyer, James Madison University; Stephen Allard, Winona State University.
This session will highlight field-based research and education by geoscientists influenced by Wally Bothner. Topics include New England geology, Appalachian tectonics, and the cross-disciplinary nature of geoscience research and education associated with fieldwork and mapping.

B. The New Bedrock Geologic Map of Vermont: New Answers, New Problems, and New Uses of Bedrock Geologic Data. Nicholas M. Ratcliffe, U.S. Geological Survey; Marjie Gale, Vermont Geological Survey; Peter Thompson, University of New Hampshire.
The forthcoming bedrock geologic map of Vermont represents a 20-year effort by numerous geologists from federal, state, and academic institutions. This session will focus on new aspects and questions associated with the geology of Vermont.

C. Asbestos: Past, Present, and Future. Cosponsored by GSA's Geology and Health Division. Catherine Skinner, Yale University; Mickey Gunter, University of Idaho
This session will discuss and overview asbestos minerals, including problems of identification for researchers and regulators, as well as common perceptions. Get up-to-date scientific information useful for mineralogists/geologists, as well as individuals responsible for community decisions who know this as an expensive hazard.

1. The Iapetan Rifted Margin and Rift History of Eastern Laurentia. William A. Thomas, University of Kentucky; Denis Lavoie, Geological Survey of Canada.
The Appalachians have long been the model for understanding orogenic belts, and this session will explore the pre-Appalachian Iapetan rifted margin of Laurentia as a foundation and framework for understanding the evolution of the Appalachian orogen.

2. Laurentian-Gondwanan Interactions in the Paleozoic. Jim Hibbard, North Carolina State University; Cees van Staal, Geological Survey of Canada; Sandra Barr, Acadia University; William A. Thomas, University of Kentucky–Lexington.
The post-Middle Ordovician evolution of the Appalachian orogen is principally governed by the interactions of eastern Laurentia with peri-Gondwanan elements. This session focuses on the similarities and contrasts in middle to late Paleozoic Laurentian-Gondwanan interactions along the length of the Appalachians.

3. Tectonic Significance of Buried Terranes of the Atlantic and Gulf Coastal Plains. Wright Horton, U.S. Geological Survey; Paul Mueller, University of Florida.
Buried "basement" terranes are one of the last frontiers of eastern North American geology. We welcome contributions defining the boundaries, geologic histories and tectonic evolution (including supercontinent cycles), early Mesozoic rifting, and influence on coastal-plain structures, neotectonics, groundwater, and hydrocarbons.

4. Strike-slip and Transpressional Tectonics in the Appalachians and Beyond. Chuck Trupe, Georgia Southern University; Kevin Stewart, University of North Carolina; David West, Middlebury College.
The Appalachian orogen experienced multiple strike-slip and transpressional tectonic events during the Paleozoic. This session will explore the timing and significance of these events along the strike of the Appalachians.

5. Vorticity and Strain in Shear Zones. Ryan Thigpen, Virginia Tech; Micah Jessup, University of Tennessee.
The role vorticity variation plays in high-strain zones has become the focus of many kinematic studies. This session will examine the various aspects of applied and theoretical vorticity and strain studies in the context of shear zone evolution.

6. Geologic Maps, Geophysical Maps, and Derivatives from Geologic and Geophysical Maps (Poster Session). Michael W. Higgins, Geologic Mapping Institute; Ralph F. Crawford, Geologic Mapping Institute.
Almost all geoscience research is based on geologic maps. This session highlights innovations in geologic mapping, data management, 4-D interpretations, applications in water and land management, and using geophysical maps to interpret crustal features.

7. Landscape Evolution in the Appalachians: Rates, Dates, and Models. Greg Hancock, College of William & Mary; Paul Bierman, University of Vermont.
The Appalachians have a long history of groundbreaking landscape evolution studies. In this light, this session seeks contributions from field, empirical, and theoretical studies examining the style and pace of Appalachian landscape evolution. We encourage submissions on studies utilizing new quantitative techniques to obtain rates and dates.

8. Recent Advances in Understanding the Geomorphology and Quaternary History of the Appalachian Region and Adjacent Regions. Todd Grote, Allegheny College; J. Steven Kite, West Virginia University.
This session will focus on advancing our understanding of the Appalachians and adjacent geologically linked regions. Recent research into terrestrial surficial processes and paleoenvironmental archives from glacial and nonglacial settings is invited. Interdisciplinary research themes are highly encouraged.

9. Evolution of the Atlantic and Gulf Coasts from Rift Margin to Passive Margin. Amy Weislogel, University of Alabama; Delores Robinson, University of Alabama.
This session encourages all investigations relating to the break-up and rifting of Pangea to evolution of the Atlantic and Gulf of Mexico spreading centers and ultimate formation of the modern passive continental margins.

10. The Integration of Marine and Non-Marine Subsurface Sediments to the Interpretation of the Stratigraphic Record of the Atlantic Coastal Plain. Jesse Thornburg, Temple University; Stephen Peterson, Temple University.
Analysis of subsurface sediments is vital for a more complete record of the evolution of the Atlantic coastal plain. This session highlights uses and applications and the interrelationship of marine and non-marine subsurface sediments.

11. Stratigraphy, Correlation, Depositional Environments, and Paleontology of Pliocene to Pleistocene MIS 5 Deposits of the Atlantic Coastal Plain. Kelvin W. Ramsey, Delaware Geological Survey; John F. Wehmiller, University of Delaware.
This session will bring together stratigraphers, paleontologists, sedimentologists, and geochronologists studying the Plio-Pleistocene evolution of the U.S. Atlantic coastal plain. Emphasis will be on correlation of coastal plain units or landforms over broad parts of the region and with isotopic records of ice volume change.

12. The Impact of Climate Change on Barrier Island-Backbarrier Systems. Cosponsored by Eastern Section, SEPM. Michael S. Fenster, Randolph-Macon College; Duncan M. Fitzgerald, Boston University.
This session encourages papers that discuss how, if at all, climate change has altered the magnitude and/or frequency of coastal processes and/or how barrier-tidal inlet-backbarrier systems have responded to process changes over a variety of spatial and temporal scales.

13. Measuring and Modeling Coastal Morphodynamics: Beaches and Shelves. Art Trembanis, University of Delaware; Adam Skarke, University of Delaware.
This session seeks to bring together researchers in coastal morphodynamics pursuing observational and modeling studies, particularly those examining bedforms from ripples to shoals and those aimed at advancing our understanding of transport processes at the coast and on the inner continental shelf.

14. Coastal and Nearshore Processes Affecting Our National Parks. Courtney Schupp, National Park Service; Mark Borrelli, Provincetown Center for Coastal Studies.
Our coastal national parks provide opportunities to experience, understand, and protect these special areas. This session welcomes contributions pertaining to coastal and nearshore processes, geomorphology, or geology within and around national parks.

15. Estuarine Sediment Dynamics. Cindy Palinkas, University of Maryland Center for Environmental Science.
This session focuses on the dynamic sedimentary processes that occur in estuaries, including impacts on benthic organisms. Processes such as sediment transport, deposition, and erosion are considered, as well as their preservation in the stratigraphic record.

16. Connecting Continent and Sea: Paleoecologic Studies of the Eastern North American Continental Margin from Coastal Plain to Abyss. Neil E. Tibert, University of Mary Washington; H. Allen Curran, Smith College.
The continental margin of eastern North America includes terrestrial and marine deposits. This session will include a broad range of paleoecologic studies from these strata that facilitate our understanding of margin development and evolution.

17. Insights from Microfossils: From Geoarchaeology and Pollution Remediation to Climate and Sea-level Change. Miriam Katz, Rensselaer Polytechnic Institute; Francine McCarthy, Brock University; Ellen Thomas, Yale University.
This session will highlight a broad spectrum of innovative microfossil applications to research issues in terrestrial and marine environments, such as geoarchaeology, pollution remediation, sea-level reconstruction, Holocene climate change, and studies of anthropogenic impact and eutrophication.

18. Eastern Ichnology: Advances in Paleoenvironmental Applications of Trace Fossils. Cosponsored by Eastern Section, SEPM. Jacob Benner, Tufts University; Ilya Buynevich, Temple University.
This session focuses on research in eastern North America, including new work in the cradle of ichnology, New England. Paleontologists working with trace fossils or carrying out neoichnological experimentation and sedimentologists utilizing trace fossils in paleoenvironmental interpretation are invited to submit.

19. Geologic and Paleoenvironmental History of the Chesapeake Bay. Rowan Lockwood, College of William & Mary; Thomas Cronin, U.S. Geological Survey.
The Chesapeake Bay provides an ideal system for exploring how coastal ecosystems respond to threats, including human activity, climate change, and sea-level rise. This session focuses on the sedimentary record of the bay, from fossils to biomarkers, and its use for paleoenvironmental and paleoclimatic reconstruction.

20. Energy Resources in the Eastern United States and Associated Environmental Effects. Devin Castendyk, State University of New York, College at Oneonta; Joseph Graney, Binghamton University.
The demand for local energy production has never been greater. This session explores traditional and alternative energy resources in the eastern United States, and potential environmental impacts associated with development of these resources. Topics include nuclear, coal, natural gas, hydropower, geothermal, biofuels, wind, and solar.

21. Case Histories in Engineering Geology, Eastern United States. James T. Kirkland, Professional Consulting Corporation; Page Herbert.
The eastern United States, with its long history and intensity of development, offers a large and varied array of geological engineering problems. This session will highlight some of geo-engineering problems and the contributions geologists have made to their solutions.

22. Selenium as an Essential Micronutrient: Geologic and Geographic Sources and Efficacy. Michalann HartHill, GHI Inc.
This session outlines selenium bioavailability in several geological environments, focusing on soils where Se concentration is often critical for transfer to humans. While Se can be considered toxic in high amounts, global patterns of Se bioavailability indicate Se deficiency might contribute to other and widespread diseases

23. Mercury in the Environment: From Maine to Florida. Julia L. Barringer, U.S. Geological Survey; Zoltan Szabo, U.S. Geological Survey; John Reinfelder, Rutgers University.
This session focuses on studies related to mercury's interactions with microbes (methylation, demethylation, reduction) and organic and inorganic constituents, mobility in different media, and atmospheric inputs in diverse East Coast environmental systems.

24. Hydrogeology of Wetlands and Watershed Processes. Timothy Callahan, College of Charleston; Vijay Vulava, College of Charleston.
This session invites contributions that demonstrate the role of the geologic framework in hydrology and water quality of individual wetlands or at the watershed scale, in both coastal and terrestrial environments, including depression and river-associated wetland systems.

25. Cave and Karst Deposits in the Eastern United States: Archives of Paleoclimates and Paleoenvironments. Russell W. Graham, Pennsylvania State University; Blaine Schubert, East Tennessee State University.
This session will focus on a wide variety of interdisciplinary records of paleoclimate and paleoenvironment preserved in cave and karst deposits in the eastern United States.

26. Interaction between Shallow and Deep Karst: Geologic, Hydrologic, Geochemical, and Biologic Indicators. Dan Doctor, U.S. Geological Survey; Bruce Lindsey, U.S. Geological Survey.
Mixing between shallow and deeper karst aquifer components has impacts on water quality, karst ecosystems, and the processes of karstification. We invite submissions that address the importance of interactions between deep and shallow components of groundwater flow in karst.

27. Ancient and Modern Carbonates of Eastern North America. Cosponsored by Eastern Section, SEPM. Bosiljka Glumac, Smith College; Sara Pruss, Smith College.
This session will be an opportunity for carbonate sedimentologists and stratigraphers to exchange ideas about differences and similarities and about prospects and challenges that various carbonate deposits of eastern North America provide.

28. Faculty and Student Perspectives on Undergraduate Research: Models, Challenges, and Best Practices. Dori Farthing, SUNY-Geneseo; Peter Sak, Dickinson College; Jeffrey Ryan, University of South Florida.
This session will highlight exemplary aspects of undergraduate-driven research. It will include models for mentoring, professional development, logistics, and strategies. Students and student/faculty teams will also present specific examples of undergraduate-driven research.

29. Innovations in Teaching Earth-System Science for the K–12 Classroom.Guertin, Pennsylvania State University-Brandwine; Tanya Furman, Pennsylvania State University.
Earth system science allows for a course of study where students learn about the connections and applications of science, technology, and society on our planet. Climate change, sustainability, and energy issues are certainly "hot topics" that require our students to have a strong background in understanding how the Earth works as a system. The systems approach enhances student learning even when SOLs focus on content and concepts from discrete subfields (e.g., geology, atmospheric science). We encourage K–12 teachers to submit their best practices for engaging students in Earth system science content.

30. The November Nor'easter of 2009 - A Preliminary Discussion of the Effects Throughout the Atlantic Coast Region.Art Trembanis, University of Delaware; Katie Farnsworth, Indiana University of Pennsylvania
During the second week in November of 2009 a historic Nor'easter, the remains of Hurricane Ida, blasted the East Coast with torrential rains, pounding surf, and strong winds causing severe flooding and erosion both at the coast, within estuaries, and on inland rivers along much of the Atlantic coast. This session will bring together scientists actively working on understanding the effect of the large November 2009 Nor'easter along the central Atlantic Region. We welcome submissions spanning effects along the entire Eastern seaboard ranging from the upper watershed down to the coast and out onto the shelf. The goal is to provide a forum for researchers to illustrate and share the characteristics of the storm (winds, rainfall, surge, erosion, etc.) from a broad suite of both remote and in situ observational systems (i.e. buoys, mooring, stream gages, satellites, post-storm surveys, etc.) together with model simulations of the storm.

Plume du jour

2009-11-18T07:00:00.001-05:00

A nice example of plumose structure, enhanced by a pronounced joint set which cross-cuts the be-plumed surface. Hammer for scale. White Mountain front, California, September 2009.

Eric Roston on Dot Earth

2009-11-17T11:52:00.004-05:00

My friend Eric Roston made a guest appearance on Andy Revkin's Dot Earth blog yesterday. Eric wrote The Carbon Age, but more importantly, he occasionally gets together with me and some mutual friends to drink homebrew. Good work, Eric: Cheers!

Yesterday's lecture attire

2009-11-17T09:00:00.003-05:00

Yesterday was the day we talked about dinosaurs and pterosaurs in Historical Geology. Accordingly, I dressed for the occasion:

(That is not me, by the way.) The t-shirt is by the very cool company Squidfire. I recommend you check out this design and their many other cool images on cool clothing at their website. Lily bought me this one - a gift much appreciated!

Citing my sources

2009-11-17T08:30:00.000-05:00

On Sunday morning, I mentioned a frozen pizza, and my interpretation of its geologic history. Afterward, Elli from UPJ wrote me a note asking if my post didn't actually quite closely resemble "Figure 1.42 in Davis and Reynolds"? (Davis and Reynolds' Structural Geology of Rocks and Regions is a popular structural geology textbook.)

Well, yep.... Yep, it does. That's the way uniformitarianism works. The same physical laws and less-than-fully-frozen pizza delivery methods that mildly deformed George Davis' pizza in in early 1980s still apply in late 2009. I'd like to point out (as a proud structural geologist) that my pizza was more deformed than Davis'. (It also had more ingredients.) Of course, he did a better job than I did, in describing and mapping that deformation:

(The full diagram also included a cross-section and a kinematic reconstruction. Used without permission, but with a sense of what I hope is 'fair use.')

In the interest of fully citing my sources, I'd like to explain my relationship to the pizza/structure analogy. Part I: In the spring of 1995, I attended one of the fun, rollicking pizza parties that Dr. J held for the William & Mary geology department. Dr. J provided blank pies and a slew of ingredients, and we hungry students could load them up as we saw fit. It was very generous of him, quite tasty, and a lot of fun. Lubricated by a goodly amount of Dr. J's red wine (which was present in gallon jugs), I (hazily) recall a fun discussion with some of my fellow geology majors. We were congratulating ourselves on having picked the coolest major around, and full of geo-ego*, our conversation focused on the fact that we could see geological principles everywhere!

Our pizza came out of the oven, and sure enough: look there! It was full of beautiful examples of (munch munch) stratigraphy! And structure! (chew chew, bite) And the ingredients were like minerals! (slosh, gulp) Wow! This is great!

Part II: The following fall, I took structural geology with Bruce Goodwin, and the assigned textbook was George Davis' Structural Geology of Rocks and Regions, first edition. And there, I found in the first chapter the pizza analogy illustrated above. With a frisson of personal recognition, I thought back to the pizza party. And I said to myself, "I like the way this author thinks! I'm going to like this class."

Indeed I did, and many years later, when it came time for me to teach structure, I turned to Davis' book, now in its second edition and co-authored with Steve Reynolds. It's still a great text, and full of good analogies and a sense of fun. I wonder how much that one diagram turned me on to structural geology: that single pizza sketch may have influenced the course of my life!

Part III: I made a pizza, and had a digital camera handy. Now you know the full story.

___________________________________________
* I hereby lay claim to coining what I'm sure will be a very useful term!

Ghost continents

2009-11-16T20:06:00.002-05:00

Omigosh. Check this out. Spooky cool!

Evaluating methane hydrates in the deep sea

2009-11-16T10:34:00.002-05:00

Eleanor Science Cafe tomorrow at the Eleanor Rooevelt High School cafeteria in Greenbelt, MD:

Evaluation of Potential Deep Sediment Methane Hydrate Deposits
Dr. Rick Coffin from Naval Research Laboratory Marine Biogeochemistry Section
5-7pm

Methane hydrates are recognized to exist in high concentrations in coastal oceans around the world. The Japanese are exploring the potential for hydrates in the Nankai Trough, off the coast of Tokyo Japan, for development as a dominant national energy source. This investigation has lead to Arctic tundra hydrate energy evaluation in the Mackenzie Delta and Prudhoe Bay by international governments, universities and industry. Exploration of for the hydrates depends on data from seismic profiling and deep sediment drilling. This approach to hydrate exploration is expensive. Recent studies have combined seismic profiles, shallow sediment geochemistry, heatflow and controlled source electromagnetics to predict deep sediment hydrate deposits. This approach provides a more thorough, less expensive, investigation prior to deep sediment drilling.

NRL has been involved in methane hydrate exploration of the coasts of New Zealand, Chile, Canada and in the Gulf of Mexico. In addition, there are current plans to survey sediment hydrate deposits off the northern coast of Alaska in the Beaufort Sea. These studies have shown a wide variation in the prediction of deep sediment methane hydrate deposits within and between the locations. General findings of these studies are the need for a thorough geochemical evaluation. Strong seismic blanking indicative of high vertical methane migration off the coast of Chile was observed to have a low vertical methane flux through the deep sediment. High vertical methane migration on Atwater Valley in the Gulf of Mexico was observed to be coupled with a high vertical chloride flux in the porewaters, which suggests deep sediment salt diapirs caused unstable sediment methane hydrate deposits. Bottom simulating reflection, coupled with seismic blanking were believe to indicate high vertical methane fluxes on the Hikurangi Margin off the coast of New Zealand. However, shallow sediment geochemical data taken through this region suggested very low deep sediment hydrate deposits.

This presentation will provide an overview of predicted methane hydrate deposits in different coastal regions and the advantages of combining different parameters in the evaluation. Work will include data from expeditions in the Gulf of Mexico at Atwater Valley and Alaminos Canyon, on the mid Chilean Margin, west of Concepion, and on the Hikurangi Margin, northeast of New Zealand. Data may be included from a September expedition on the Beaufort Sea. The approach will provide an overview of the benefits and issues with the interpretation of deep sediment hydrate deposits using different approaches for the field survey. This presentation supports combining a variety of parameters for these surveys.

Job opportunity in our lab

2009-11-16T10:06:00.004-05:00

Come be the Annandale campus' new Physics/Geology lab tech!

The position description is now available on the NOVA HR website.

2012

2009-11-16T07:49:00.002-05:00

Yesterday I went to see 2012, the new movie by Roland Emmerich. It was a LOT of fun. I love so-called "disaster porn" movies, the genre including Dante's Peak, Volcano, Cloverfield, Independence Day, the Day After Tomorrow, Deep Impact, the Core, etc. What these films have in common is that they gratuitously display major scenes of destruction as a way of luring audiences to the theater. Most have a plot stapled on too! And maybe some pretty celebrities!

The science is not all there, though. I'm sure you're shocked to hear that.

Here's Emmerich's scenario:
Planetary alignment --> solar flares --> neutrino storm --> neutrinos heat up Earth's interior --> crust gets detached and starts sliding around willy-nilly --> ~~hilarity~~ apocalypse ensues

Here's the problems with that:

Planetary alignments don't trigger solar flares.
Neutrinos (mostly) don't interact with matter in the Earth. (50 million neutrinos will pass through your body today without any issues that we're aware of.)

...but if you ignore those two basic fundamental problems, you can enjoy the death and destruction that result. It's a smorgasbord for the eyes.

One of the main characters is a geologist, which is cool. The scene of Yellowstone erupting was probably the neatest part for me, geologically. Even crazy man Woody Harrelson thinks so, and it's the last thing he ever sees. The magnitude 10-plus earthquake that hits southern California/Las Vegas is pretty awesome visually, but doesn't really square with geological realities of how earthquakes happen. Basically the way Emmerich runs the show, soCal breaks into a huge number of separate chunks which mainly move apart from one another, although occasionally they exhibit convergent motion (maybe 1% of the time). Mostly, it's huge chasms opening up, and people/cars/buildings/airplanes/trains/Russians dropping into them. And of course, "California slides into the sea" (that old trope which ain't actually what geologists predict for the Golden State*).

There's a plot, too, but who really cares about that? That's not why you go to see 2012. So I won't even bother. Go for the effects; revel in the destruction of the world, but try not to think about the death of billions. It's all about planetary chaos, adrenaline, eye-popping awesomeness. You know you like to watch.

Some reviews worth reading:

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* A better depiction can be seen in the AGI-produced Faces of Earth, episode 2, where Los Angeles (still a city much like the current one ~10 million years in the future), atop the block of continental crust west of the San Andreas Fault, slides past San Fransisco, briefly merging the two megalopoli into one.

Slumped pizza

2009-11-15T07:45:00.001-05:00

This pizza-ite clearly passed into the brittle-ductile transition while it was vertically-oriented. This event translated coherent ingredients downward, presumably along less competent flowing cheese/dough/slush surfaces. High-contrast olives serve as good marker units for detecting the overall kinematics: note their greater concentration at the paleo-bottom of the pie (also bottom of this photo). It is inferred that these olives were originally dispersed across the face of the pizza-ite at approximately equal distances. The overall pie has strained from an original circular shape to an elliptical one, and detached from the basement cardboard along a major fault. The "top" of the pizza-ite may therefore be regarded as an overall extensional regime, while the "base" of the pie is compressional. The highest-pressure zone at the base appears to have metamorphosed up some new substances, including an ice/cheese amalgam (darker yellow).

Subsequent to this photograph being captured, the pizza experienced a high-temperature, low-pressure event which has been theoretically located to the second rack of my oven, and then was broken into eight ~equal area terranes separated along a radial series of fractures. An episode of physical weathering pulverized the pizza-ite, followed by chemical disaggregation in a low-pH medium. The energy released by this process was sufficient to power the typing of keys on a keyboard, and ultimately generated a new entity: a blog post. Through the twin miracles of digital technology and structural interpretation, we can work out that the protolith of the blog post was the deformed pizza. Careful dating of this blog post reveals it passed through closure status at 7:45am on November 15, 2009.

The Shenandoah basement complex

2009-11-14T11:14:00.008-05:00

These days, I'm engaged in the lovely process of rediscovering the geologic record of Shenandoah National Park. This 'rediscovery' was prompted by the recent Virginia Geological Field Conference based at Big Meadows. While I wasn't able to attend in person (I was in Yosemite that weekend!), colleagues like Pete Berquist and John Weidner were there, as well as three of my Rockies students from last summer. They've all shared their perspectives on the conference with me, and John loaned me a copy of the field guide to the conference. This guide, authored by other colleagues like Chuck Bailey of William & Mary and Scott Southworth and Bill Burton of the USGS in Reston, makes for great reading. I'd link to it so you can read it too, but it's not online.

The guide led me to the revelation that there is a new geologic map of the park and the surrounding area that was published earlier this year by the survey. This map* is authored by Chuck, Scott, and Bill, along with their peers at the survey and other institutions. Why wasn't I informed? (Just kidding) It's a beautiful work of art and science. I'm having the NOVA duplicating services team print me out a copy this week.

The new insights offered by the map (and the VGFC field guide) include the fact that the oldest rocks in Shenandoah National Park are diverse and complicated. It used to be that geologists considered these rocks to be a granite gneiss called "the Pedlar Formation," which was intruded in places by younger granitoid plutons. Modern work in the park has revealed that it's more complicated than that. There are a dozen or more separate rock units comprising what the pros are now calling "the basement complex." These rocks are distinguishable based on texture, mineralogy, and age. (These newer, more precise ages are one of the key advances of recent work by John Aleinikoff of the USGS: the granitoids and their metamorphic successors have crystallization ages ranging from 1,183 Ma (+/-11 Ma) to 1,028 Ma (+/- 9 Ma).

I've updated my Shenandoah web page to reflect the new preferred terminology plus these new dates. More updates to come -- I've got many new tidbits of inspiration from reading the 100+ page write-up that accompanies the new map. The web page, like all of my web pages, is a work in progress. Nothing makes that clearer to me than a steaming helping of fresh science!

When I was out in the park last weekend, I found this new outcrop of the basement complex, which shows some of this intriguing diversity:

Annotated version:

The outcrop is on the hike over Bearfence Mountain, described (and mapped) in the new VGFC field guide. It's a granite gneiss, partially altered to unakite (the plagioclase and pyroxene in the graniotid reacted in the presence of water to generate epidote. A pronounced foliation is cut by no less than 3 separate sets of fractures, two of which are filled in with fibrous quartz, and another by something dark. The granitoid formed during the Mesoproterozoic Grenvillian Orogeny, and was deformed later in that same episode of mountain building. The fractures formed at some point after that: just when, I can't say. Vein sets 1 and 2 are infilled with apparently identical compositions, which would be consistent with them being contemporaries. Vein set 3 has something else lining its fractures. At first I thought it was just mildew, but Elli suggested some mineralogical possibilities. Vein set 3 does not show the same amount of dilation as the other two sets. Cross-cutting relationships show vein sets 1 and 2 cross-cutting vein set 3, which suggests I was too hasty in labelling them in my photo. "3" is the oldest; "1" and "2," despite their names, are younger. Maybe they're related to Neoproterozoic breakup of Rodinia, or Alleghanian mountain-building, or uplift? So many mysteries...

More to come on this topic, surely, as I get re-introduced to my local national park.
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* Southworth, Scott, Aleinikoff, J.N., Bailey, C.M., Burton, W.C., Crider, E.A., Hackley, P.C., Smoot, J.P., and Tollo, R.P., 2009, Geologic map of the Shenandoah National Park region Virginia: U.S. Geological Survey Open-File Report 2009–1153, 96 p., 1 plate, scale 1:100,000.

Virginia state schools accepting more out-of-state applicants

2009-11-14T07:30:00.001-05:00

Ouch. Rough stuff for those in-state students applying to in-state schools. (Out-of-state students pay more money...) from the Washington Post.

Wally Broecker's talk at Carnegie

2009-11-13T15:30:00.006-05:00

Last night, Lily and I went down the street to the Carnegie Institution to catch a guest lecture by climatologist Wally Broecker of Columbia University. Broecker won the Balzan Prize last year, and this was 'the Balzan Lecture.'

Broecker was introduced by the Swiss and Italian ambassadors to the United States, as well as another man whose title was not made explicit, but who had the most pronounced eyebrows I have ever seen on a non-cartoon character.

Broecker's PowerPoint was written in all capital letters, and all Helvetica. It was a bold font for a man who has a reputation for boldness. He was blunt in his assessment of the climate crisis: "The problem is huge, and I wish I could live for fifty more years to see how it all plays out," he said. He pointed out that we are currently at "390" parts per million carbon dioxide in our atmosphere, up over a third from pre-industrial levels of ~280 ppm. "We're going up by two per year," he said, and that means that we will be at 450 ppm within 30 years. "If we want to stop at 450 ppm, we're going to have to go on a World War II footing."

He estimated that about 80% of humanity's energy comes from carbon, and stated "We must cut back to zero net emissions." However, he acknowledged that it is unlikely that we will be able to do this in the time we have (~30 years, see above), so he has come to the conclusion that the only way we're going to be able to avoid a doubling of CO2 is to capture carbon dioxide from the atmosphere and sequester it somewhere.

He showed both Keeling curves: Dave Keeling's CO2 data from Mauna Loa, and Dave's son Ralph Keeling's CO2 data and O2 data from La Jolla. (I've reported before on how compelling this oxygen data is: it's definitive information that shows the rise in atmospheric CO2 must be coming from the combustion of fossil fuels, a process which consumes oxygen by bonding it in an exothermic reaction to fossil fuel carbon.) Broecker then predicted that we are going to at least double CO2, triggering a rise in temperature of about 3.5 degrees C. He said, "This will not be a total catastrophe, but it's going to be a huge mess." He discussed ecological changes which will likely result - species shifting poleward or towards higher elevations, but able to migrate at different rates, which will be rough in terms of keeping ecosystems coherent and functional.

He said that water vapor is actually the biggest contributor to the greenhouse effect, and that it amplifies the warming caused by CO2. The partial pressure of water vapor over the oceans goes up by about 7% with each degree of warming: this means that a degree of warmth caused by CO2 would trigger a triple warming because of its effect on water vapor. He discussed uncertainties in our understanding of the climate system: the role of aerosols, the role of clouds. "We're perturbing climate," he said, "on a planet where we don't understand the whole thing."

He discussed his Columbia colleague Klaus Lackner, who has developed a plastic compound that can capture carbon from the air. Lackner has proposed a facility using filters of this compound, and estimates each facility, about the size of a shipping container, could remove 1 ton of CO2 per day, about the equivalent of 20 U.S. automobiles' emissions. Each facillity costs about as much as a car, so Broecker proposed paying for them by tacking a 5% surcharge onto automobile sales. They also cost money to maintain, and the calculation suggested that if we added a tax of 25 cents per gallon, we could generate enough income to maintain these carbon-capturing facilities.

The grants that Lackner got to develop this technology totaled about $6 million. Broecker pointed out that we pay (Yankee) baseball pitchers about $6 million per year, and that it's a shock and a shame that so very, very little is being invested in solving the problem of accumulating carbon emissions. He said, "That is peanuts compared to the amount of money that is being spent on any other serious problem on this planet."

Norway's 13-year record of success in storing captured carbon in deep sea sandstone reservoirs was his next topic, and he went on to suggest that we should try trial experiments where we inject CO2 directly into the deep sea's water, given that it has a ~1000-year circulation time. Below 3500 m depth, liquid CO2 is more dense than seawater, and would either sink or form clathrate slush. Broecker suggested it's quite possible it could be stable down there, and we need to figure out if in fact it is before it's time to actually start injecting it. Greenpeace opposes this idea, and Broecker said, "environmentalists are their own worse enemies." In Iceland, an experiment is being done where the small amount of CO2 that comes up in geothermal water is being re-injected into basalt. He pointed out that Iceland is investing MUCH more per capita in carbon capture and sequestration experiments, and lamented that the rest of the world was being so lackadaisical with its funding.

Finally, he discussed the 'geoengineering' solution of pumping SO2 into the stratosphere to filter out some incoming solar radiation (as happened naturally in the aftermath of Mount Pinatubo's 1984 eruption). Broecker and colleagues did a paper back then to calculate how much SO2 we would need in the stratosphere to counteract the warming effect of CO2 + H2O vapor, and found it to be about 30 million tons of SO2 per year. He calculated that you could deliver it with 747 aircraft, but you would need 250 of them, flying around the clock, year-round, to do it. The cost would be about $15 billion. Whether he advocated this approach was unclear to me, but that's where we ended up. The end.

Applause, more "hosting" from Mr. Eyebrow (who tried to inject a positive note into the grim discussion: "It will be okay. We're so smart; we will figure it out!"), and some audience questions. A walk home for Callan and Lily, followed by a gin and tonic.

Final GSW of the year

2009-11-13T14:40:00.001-05:00

Wednesday, December 9, 2009: 1437th Meeting

PRESIDENTIAL ADDRESS

Compression, extension, compression:

an Appalachian geologist's 25-year journey through the Wilson Cycle

Bill Burton, U.S. Geological Survey, Reston

Refreshments start at 7:30 p.m. The formal program starts at 8:00 p.m.
Meetings are held at the John Wesley Powell Auditorium
2170 Florida Avenue NW, Washington, D.C. (directions)

Charles Darwin has a posse

2009-11-13T07:52:00.003-05:00

Heh! I love it.

Via the Axis of Evo blog. (You should also check out author Colin Purrington's Flickr photostream.)

Idiots!

2009-11-12T08:27:00.003-05:00

The past week has been one of the more frustrating weeks for me at my workplace. It's been a litany of bureaucracy and incompetence, and my faith in (some of) my coworkers has dropped precipitously. I had to send twenty e-mails to get the college Catalog updated with my correct position title and educational information. Yesterday, I saw a delivery man pushing a cart, opening the door with the handicap access motor (wasting the building's heat), and his special cargo that he needed the cart for was... a lone letter measuring 8.5" by 11"! The particular incident that's raised my ire this morning is the following:

We run these one-credit Field Studies in Geology courses, GOL 135. The Spring 2010 Schedule of Classes lists the different sections of GOL 135 inconsistently across NOVA's different campuses. Here's a comparison between the Alexandria and Annandale campuses' listings. Guess which campus is going to have its sections fill up with students based on this? Guess which campus is probably going to have to cancel classes due to insufficient enrollment? (Guess which campus I work at?)

Someone has screwed up here, and I'm not pleased about it. Grrr.

New TED talk from Edward Burtynsky

2009-11-12T05:40:00.005-05:00

I've mentioned photographer Edward Burtynsky before. He's got a fresh new talk up on the TED website -- a short one, just under 4 minutes. The theme: oil's landscape. Check it out!

Oncolites

2009-11-11T11:11:00.011-05:00

A block and half away from my new condo, there stand a trio of imposing churches, at the corner of 16th Street NW and Columbia Road NW. A Google Map of the corner in question:

The one I want to discuss today is on the southwestern corner of this intersection. It's currently a Unification Church, but the structure was built in 1933 as the first chapel of the Church of Jesus Christ of Latter Day Saints (the Mormons) in DC. According to Chris Barr, an attorney and amateur paleontologist who is compiling an "Accidental Museum of Paleontology" about DC's building stones that include fossils, "two grandsons of Brigham Young contributed to its design and artwork, and the church consciously echoes the design of the Mormon Temple in Salt Lake City." Not only that, but they opted to use exterior buuilding stone shipped in all the way from Utah!

Chris's website about all the fossil-containing DC building stones is nearing completion, and I will post a link here when it is live. In the meantime, I wanted to share some of the information he compiled about the rocks which makes up the exterior of the Unification Church: Utah Bird's Eye "Marble."

Here's what it looks like:

The elliptical shapes you're seeing here are oncolites (sometimes called "oncoids"), and they are essentially little ellipsoidal stromatolite balls. A little grain of this or that gets encrusted by calcifying algae / microbial slime, and layer upon layer gets added with addition growth of those slime layers, growing up through the calcite they trap. It's not a true marble, in other words: it's a limestone.

These limestones with oncolites originated in a large freshwater lake called Lake Flagstaff, approximately 66 to 58 million years ago (Paleocene). The lake was present in northeastern and central Utah. According to Chris Barr, the stone used on the exterior of the Unification Church was quarried at "8,000 feet in elevation, in what is now the Manti-La Sal National Forest in the mountains more than 60 miles south of Salt Lake City."

Some of them have partial void spaces internally, which have since been filled by sparry calcite:

The horizontal layering of the non-spar gunk inside these voids provides a little paleo-horizontal "level" to help reconstruct which way was "up" when these sediments were deposited. (This particular block is on its side in the wall of the church; I've rotated the photo to paleo-up using Photoshop. (That's also where the arrows come from!)

For some perspective on the recent history of the building where these cool rocks are displayed, I'll quote from Chris Barr's soon-to-be-released website: "Changes in the neighborhood, the growing needs of the Mormon community, and the prospect of costly repairs to the walls, led to the end of services in 1975 and the sale of the chapel, which was purchased by the Unification Church in 1977. The Mormons constructed a new, larger chapel in suburban Bethesda - a structure that also provides a visible reference to the temple in Salt Lake City."