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.

Labels: california, conferences, faults, granite, pleistocene, rivers, travel, volcano, weathering

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.
__________________________________________
* 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.

Labels: blue ridge, conferences, granite, igneous, metamorphism, national parks, proterozoic, shenandoah, structure

Returning now to some of the stuff I saw when I was out in Bishop, California for the GSA Field Forum I attended in September. One of the cool little spots we visited was "the flipping fault," a location on the Volcanic Tableland north of Bishop where an east-dipping fault scarp dies out and a west-dipping fault scarp starts up. Check it out:


Here, try one with annotations:


Here's a Google Map of the location, as seen from the perspective of a passing turkey vulture:

Notice how the road, Casa Diablo Road, goes right through the notch where the two meet. Complicating the picture a wee bit is a Pleistocene drainage channel which uses the same route between the two scarps (and diverges from the road in the lower-left).

Another view, further back and higher up:


And of course we must annotate that one too:


Recall that these are normal faults busting through the Bishop Tuff's upper welded layer, the "Ig2." In the annotations, I've sketched in the approximate position of the "hanging-wall cutoff" (lower boundary of each scarp) and the "foot-wall cutoff" (upper boundary of each scarp).

There are roughly equal numbers of east-dipping and west-dipping faults on the Volcanic Tableland. Originally, some creative structural geologists wanted to interpret this feature as an overall "propeller" shaped fracture: a so-called "flipping" fault (as in, it's one single fault that flips its dip direction in the middle). However, this was not the interpretation of our workshop leaders, who suggested that it was simply two faults that started independently and then propagated towards one another.

Taking a fresh look at these images now, almost a month after I visited the outcrop, I find that I agree with them. One thing that seems obvious to me now is how the east-dipping fault truncates on the face of the west-dipping fault scarp. My annotations reflect this interpretation. What do you think?

Labels: california, conferences, meetings, structure

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

Microbial Mats in siliciclastic sediments from the Archean to present

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

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

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

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

Topics include:

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

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

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

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

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

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

Labels: colorado, conferences, microbes, stromatolites

Whew!

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

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

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

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















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

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

Today I got the news that I've been accepted to two professional development opportunities that I'm really looking forward to:

1. SERC workshop: Strengthening Your Geoscience Program, June 2009, Williamsburg, Virginia
2. GSA Field Forum: Structure and Neotectonic Evolution of Northern Owens Valley and the Volcanic Tableland, California September 2009, Owens Valley, California

Yay!

Any other geobloggers or geoblog-readers going to be at either?

Labels: california, conferences, virginia

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

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

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

Yesterday, I mentioned the results of the Virginia DGMR symposium's breakout session on Blue Ridge geology. Today, for completeness' sake, I'll also post the results of the other two breakout sessions (one on the Valley and Ridge province, and one on water issues):

Session 2: Unresolved Issues in Valley and Ridge Geology
In general, the consensus was that continued support for detailed geologic mapping is needed, which provides essential information for a number of major issues that need to be resolved. Major issues discussed during the Breakout Session generally fell into one or more (much overlap) of the following categories:

Geologic Framework:
Need to find better ways to communicate the value of geologic mapping (e.g. beyond the anticipated development along the I-81 Corridor).
Better communication between geologists working in the BR and VR regarding the timing and influence of major tectonic events; presently somewhat disconnected.
Evaluate the influence of basement normal faults.
Better understanding of the sequencing of thrust faults in the VR.
Better understanding of the transition between brittle and ductile fracturing in the VR.
Influence of the Rome Trough on VR structural framework.
Better understand the link between Allegheny Front and BR overthrust.
Better define stratigraphic units with economic and geohazard potential that are currently lumped (e.g. SDu, Ols, etc).
More focus on deep stratigraphy, where there is potential for deep saline aquifers that may provide geologic storage of CO2.

Geologic Hazards:
Identify, evaluate, and prioritize geologic hazards in VR.
Karst/sinkhole digital database; better understanding of the interplay between geologic controls and land use.
Large block slides, recognizing risk areas.
Better understand the nature of brittle on ductile fractures in context of subsidence risk along the western margin of the Blue Ridge
Quaternary history (e.g. evaluation of flood risks)

Economic:
Better understand the distribution of high-Ca limestones; not just limited to the middle-Ordovician units.
Stratigraphic relationships between Devonian shale units (e.g. Millboro, Marcellus)
Evaluate occurrences and distribution of non-polishing aggregate resources.
Evaluate occurrences and distribution of high purity silica (glass sands); (e.g. depositional character of the Oriskany).

Other:
Source and structural implications of Eocene-age igneous rocks (Highland Co) and alkaline dikes (Augusta Co).
Need for improved educational outreach.

Session 3: Integrating Geologic and Hydrologic studies - Benefits and Challenges
The group was divided into geologic information providers, hydrologic information providers, and hydrogeologic information users. The provider groups developed a list of the most important types of information they provide. The User group developed a list of the most important types of information they need. Based on the results of this exercise and the interest of the group, the remainder of the meeting focused on addressing gaps in available information for end users.

Geologic data providers provide:
Geologic formation information - descriptions, structure data, "cover" materials
Fracture/joint data and analysis
Detailed and regional maps
Ground truth on karst features

Hydrologic data providers provide:
Well data - location, yield, logs, geochemistry
Spring data - location, discharge, geochemistry, dye trace results
Water use information - ground water and surface water
Technical /Assistance
Hydrographs

Users of hydrogeologic information need:
Geologic maps at an appropriate scale.
Water well data - yield, depth to water table, etc.
Hydrographs

Users noted the following characteristics of information would be helpful:
Widely available and accessible information (Internet)
Standardized - uniformity of format and methodology (example pumping tests) on at least a statewide basis
Geologic descriptions and maps could include a characterization of saprolite.

Providers and users believed there was good agreement between the type of information that is being provided and that which is needed. The clear problem was recognized to be a lack of data in many places and the lack of easily accessible information (digital format, available on internet)
To address this problem, it was suggested the users of hydrogeologic information may be able to provide some assistance, such as:
Well data - construction characteristics, yield, drawdown, geochemistry over time
Soil data - maps, field notes
GIS Capabilities and data processing - especially county governments.

An identified issue:
Disconnect in some cases between geologists and soil scientists

Next Steps:
Water for America initiative may be an opportunity for geologic and hydrologic data providers to work together at the state level and provide hydrogeologic information to end users.

Based on USGS efforts in Northern Shenandoah Valley, integrated studies have both benefits and challenges. A future meeting to highlight these may be helpful to state level geologists and hydrologists.

Labels: caves, conferences, geology, valley and ridge, virginia, water resources

At the DGMR Blue Ridge / Valley & Ridge Symposium the other week, we had a productive hour-long brainstorming session about unresolved issues in the geology of those two physiographic provinces.

I only attended the Blue Ridge session, and with the blessing of the conference organizers, I'd like to share the results of our ruminations here:

Unresolved issues in Blue Ridge Geology

General Outcomes:
Participants would like to see this as a start to a new state geologic map for 2015.
Participants would like have follow-up workshops to discuss these issues in detail.
Participants would like to develop research needs proposals on these key topics.

Specific Issues:
1. Ramp separating the Cambro-Ordovician carbonates from the rock of the Blue Ridge
a. What is its position?
b. Is it "thick" skinned?
c. Can field work (alone) resolve this?
d. What is its age?
How might this question be resolved?
A. Detailed geologic mapping at 1:24,000 scale across the Blue Ridge / Valley and Ridge transition
B. Applying geophysical techniques such as
a. Seismic reflection
b. Gravity studies
c. Reprocessing old data and reassessing old interpretations
C. LIDAR

2. Working out the problems with the Blue Ridge nomenclature and unit and fault correlations
a. Issues with variability in terminology and correlations across Virginia and between Virginia and North Carolina.
b. Map distribution of faults along the Blue Ridge - need to correlate their timing and extent
How might this question be resolved?
A. Detailed geologic mapping at 1:24,000 scale along the Blue Ridge (N/S) and across the Blue Ridge (E/W).
B. Models for the Blue Ridge need to be presented, discussed and synthesized.
C. Developing a basement "tool kit" for Late Proterozoic rocks: Since we can't afford to date every rock, there is a need for key characteristics for each unit to be agreed upon and applied in the field.
D. Expunge archaic terms and agree upon an appropriate vocabulary.
E. Regular focus group meetings and field meetings are necessary to resolve these issues.

3. When did the Blue Ridge develop its topographic relief?
a. Timing?
b. Is it in a steady state?
c. What is the history of the various erosional surfaces throughout the BR's evolution?
d. How does this correlate with the other physiographic provinces?
How might this question be resolved?
A. Detailed geologic mapping at 1:24,000.
B. Utilize low temperature chronometers such as U/Th/He at a sufficiently detailed spatial scale.

4. Role of the Mesozoic system in the Blue Ridge story and geometry.
How might this question be resolved?
A. Detailed geologic mapping at 1:24,000.
B. Need more geophysical studies.
C. Examine the effects/association of these fractures with water
D. Examine the relationship between features and mineral resource deposits
E. More detailed fracture studies are needed
F. Compare and contrast the Mesozoic rifting with previous rifting cycles
G. A seismic risk assessment needs to be done.

5. Mylonites in the Blue Ridge
a. Triclinic deformation
b. Palinspastic restoration of the Blue Ridge in 3 dimensions.
c. Oblique convergence in Thornton Gap area.

6. Is there an unconformity between the Catoctin and the overlying sedimentary units?

7. New mica ages and their implications for deformation timing
a. Is this related to thrusting sequence?
b. Ages in the Swift Run and Weverton ages were likely the maximum temperature. Deeper rocks likely represent cooling ages.

8. Issue with the cover sequence west of the Blue Ridge - just where is the PreCambrian / Cambrian boundary?
a. Middle of the Chilhowee group?
b. Is all of the Chilhowee group Cambrian in age?
c. Is it in the Lynchburg formation?

9. Are there any Ediacaran fauna in any of the Neoproterozoic sediments?

10. There is a need to reconstruct paleoenvironments in the Blue Ridge
i.e. Mt. Rogers' glacial deposists, etc.

11. Paragneiss story
a. What is the time/temperature path these rocks took?
____________________________________________________

Again, I'd like to thank Amy, Matt, Laurie, and the rest of the dedicated staff of the Division of Geology and Mineral Resources for organizing the symposium and following up with this break-out session digest. Everyone I know who was there felt it was really useful. Facilitating discussions like these between geologic researchers is a key function of a robust state geology agency, and it chagrins me to think there will be less of this in future years due to the recent budget cuts.

What do you think of this list? Are these the most important issues in Blue Ridge geology? What would you add or refine?

Labels: blue ridge, conferences, geology, virginia

As I mentioned yesterday, the Virginia Department of Geology and Mineral Resources has an excellent rock garden outside their office in Charlottesville, displaying a diverse suite of large rock samples from across the state's five physiographic provinces.

Here's Rick Diecchio (George Mason University) providing a sense of scale for the rock garden:


Here's a few of the samples that caught my eye, with my shoe providing a sense of scale (size 12, specifically) in each image...

Aquia Formation sandstone with Turitella fossils (Paleocene); King George County:


Balls Bluff Siltstone with mudcracks (Triassic); Culpeper County:


Conococheague Formation collapse breccia (Cambrian); Augusta County:


Cranberry Gneiss (?) showing well-developed lineation (Mesoproterozoic); Grayson County:


Kyanite quartzite (probably Ordovician metamorphic age); Prince Edward County:


Fossil Sigillaria tree trunk from the Wise Formation (Pennsylvanian); Wise County:


Unakite, the state rock of Virginia according to some (Mesoproterozoic); Rockbridge County:


Here's a link to the PDF (1.82 MB) with all the details about all the rocks in the garden, an impressive achievement just like the symposium.

Labels: conferences, fossils, igneous, meetings, metamorphism, primary structures, sediment, virginia

I spent this past Friday (12/12) at a symposium put on by the Virginia Division of Geology and Mineral Resources, in Charlottesville, Virginia. This excellent branch of our state government just had their budget disproportionately slashed, but they aren't letting it bring them down. In fact, they're breaking new ground in their unparalleled service to the geological public. In honor of the groundbreaking Virginia geologist Tom Gathright (who was in attendance), they organized a day of scholarship and conversation about recent advances in the geology of the Blue Ridge and Valley & Ridge physiographic provinces.

Rick Diecchio (of George Mason University) and I drove down together, getting up at the unholy hour of 5am in order to get there on time. Once there, we trundled past their excellent outdoor rock garden (about which I will post tomorrow), and inside to join the gaggle of more than a hundred geologists from the USGS, Virginia universities and community colleges, transportation agencies, environmental agencies, and the DGMR itself.

The morning session consisted of a series of talks about the Blue Ridge. We heard from Bob Millici (USGS), Scott Southworth (USGS), Chuck Bailey (W&M), Mark Carter (DGMR), Bill Henika (Virginia Tech), and Karen Rice (USGS). I won't post any of the juicy data details we heard, for fear of spilling any unpublished beans, but there was some cool stuff we learned about. There was also a poster session in the well-appointed library. Pete Berquist (Thomas Nelson Community College) and I had lunch out in the rock garden, where I chatted with three undergrads from our alma mater.

The afternoon session was given over the the Valley & Ridge province. We heard from Scott Eaton (JMU), Steve Whitmeyer (JMU), Dave Weary (USGS), Randy Orndorff (USGS), Joel Maynard (Virginia Department of Environmental Quality), and Wil Orndorff (Virginia Department of Conservation & Recreation, Division of Natural Heritage).

My favorite part of the day, though was a break-out session to discuss unresolved issues. There were three break-out groups: one for water issues, one for the Valley & Ridge, and one for the Blue Ridge. I went to the Blue Ridge one, and really enjoyed this unique setting. I mean, here I am in a room with a bunch of people who spend the majority of their professional time trying to understand how the Blue Ridge got put together, and we're just brainstorming together, thinking about big unknowns, big gaps in our understanding. The DGMR staff is compiling these results, and once they're distributed out to the participants, I'll post them here on NOVA Geoblog. We've been asked to share the results. Since there were two geobloggers in the room (me and Chuck), we reckoned that's a quick way to disseminate some of our ideas.

I'd like to thank the DGMR for putting on such a great meeting, in particular during such lean and uncertain times. The day was positive, affirming, and valuable on many levels. Readers, remember that you (yes, you) can still write to the governor and other state officials to protest the crippling 75% reduction in the DGMR staff.

Labels: blue ridge, conferences, geologists, meetings, valley and ridge, virginia

I've already posted some images from the VCCS Science Peer Conference a week and a half ago. Outside the offices of the Wintergreen Nature Foundation, they've arranged a series of large charismatic rock samples from the region. Some of them are from the Blue Ridge (where Wintergreen is located) and some are from adjacent physiographic provinces. These samples are from the Valley and Ridge province, showing some cool features sometimes found in sedimentary rocks.

First, some articulate brachiopod fossils in quartz sandstone (internal/external molds). This wasn't labelled as to its source formation, but it looks a lot like the Oriskany Sandstone, a major ridge-former in the Valley and Ridge. Quarter for scale.


Second, a breccia in limestone. (FYI, Andrew's Oakland Geology blog has another nice image of breccia today.) Perhaps a collapse breccia? Again, the sample wasn't labelled, so I have no idea which formation it was derived from. The white in-filling is calcite. Quarter for scale.

Labels: conferences, fossils, sediment, valley and ridge

The Virginia Community College System (VCCS) organizes conferences occasionally where faculty in different disciplines can get together. This weekend was the "peer conference" for the natural and physical sciences. It was held at the lovely mountain resort called Wintergreen, in central Virginia's Blue Ridge Mountains.

Here's a map of the area:

That's the Shenandoah Valley on the left (part of the Valley & Ridge province), the Blue Ridge in the middle (running from NE to SW), and the Piedmont province on the far right. Wintergreen is a bit SW of Charlottesville.

The conference was fruitful and interesting. I enjoyed getting to meet a bunch of the other VCCS geology faculty and discussing what we want to do in the future in terms of supporting one another and professional development. I gave a talk about new technologies in geology instruction, which included information about the geoblogosphere and other sundry web resources I use. My colleague Erik Burtis at NOVA-Woodbridge led us on a cool "field trip" to Glacial Lake Missoula, via Google Earth.

I spent a lot of time talking with Pete Berquist, from Thomas Nelson Community College, discussing next summer's Regional Field Geology of the Northern Rocky Mountains course. We laid out a series of goals for the students, and created a tentative itinerary. Pete and I took a great hike at the end of the first day, poking around in the rocks and watching the sun set over those gorgeous mountains. Friday evening, there was a cool astronomy session, where Ed Murphy from UVA showed us the Ring Nebula, the Andromeda Galaxy, and assorted other stuff in outer space. He had a great laser pointer that extended a green laser line up about 80 feet into the sky... Very useful for pointing things out. Low light levels in the forested mountains meant excellent stargazing. Saturday morning, Bill Warren of Lord Fairfax Community College gave a good talk about the global energy crisis, and potential solutions. I picked up a few good resources there that I'll use next semester in teaching Environmental Geology. And then when the conference concluded, there was a geology "hike" out to look over the landscape. By driving us to a couple of different overlooks, Doug Coleman of the Wintergreen Nature Foundation showed us spots where we were able to look east into the Piedmont, and west into the Valley & Ridge. Pretty cool, though we didn't look too closely at the actual rocks exposed there. Fortunately, I have an inclination to do that on my own... as you'll see below:

Catoctin Formation greenstone (meta-basalt), showing chlorite-rich portions (left) and epidote-rich portions (right). Quarter for scale.


More Catoctin, the volcanic breccia layer. Lots o' epidote. Quarter for scale.


Is this a quartz vein or a granite dike?
At first glance, it appears to be your standard hydrothermal quartz vein full of milky quartz, but then you'll notice that it's not just quartz. There are also two crystals of orthoclase feldspar in there. (The dark shapes are just empty holes & shadow, not mafic minerals.) I pointed this phenomenon out before, but I'll state it again: I think that hydrothermal quartz veins and granite dikes are not separate phenomena, but points along a spectrum of composition. Quarter for scale.

Looking southeast towards the Piedmont:


Looking northwest towards the Valley & Ridge:

Labels: appalachians, blue ridge, conferences, igneous, metamorphism, piedmont, valley and ridge

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

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

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

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


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


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

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

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


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


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

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

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


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


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


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


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


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


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


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


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


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

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


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

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

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

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

Here's a Google Map of the mountain:


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

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

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

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

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

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


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


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


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


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


Honors students ask questions of Mike:


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


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


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

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

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

Geo-bloggers: It's your last chance to sign up for Science Online '09.

Chris Rowan and I are both planning on attending. Hopefully some other geo-bloggers too?

Got this today from the conference organizers:
"Registration is almost full! We are already at 196 registrants - and the capacity is 200. Counting on some people to unregister or not show up, we will cap at 230, but we expect to get there within the next day or two - so it is the last chance to register right now. If something comes up later, you can unregister easily...."

Labels: blogs, conferences, meetings

Hoo boy! A busy trio of days for me. Thursday and Friday were devoted to an intensive 16-hour Wilderness First Aid training course (WFA). And today I led a twelve-hour field trip to Shenandoah National Park.

As you may recall, I got a grant to cover the tuition for six instructors (four from NOVA, two from Thomas Nelson Community College in Hampton, VA) to get WFA Training. Because he is totally cool, my dean also threw in $500 to cover an additional two instructors from our division on the NOVA-Annandale campus.

So, thanks to the grant and my dean's add-on, eight people who lead field trips for the Virginia Community College System got free Wilderness First Aid training! I'm pretty excited about that. Now, I think we stand a much better chance of saving a student's life if something were to go wrong on a trip.

The training was pretty intensive. Nancy Chamberlain of our Parks & Recreation program organized the event (assisted by geology student Quinn F.), and kept us well fed. The training itself was provided by Wilderness Medical Associates. They did a great job.

Here's the crew:

From left to right, that's Victor Zabielski (NOVA-Alexandria), Beth Doyle (NOVA-Alexandria & Annandale), Jen Martin (TNCC), Erik Burtis (NOVA-Woodbridge), Pete Berquist (TNCC), Ken Rasmussen (NOVA-Annandale), me (NOVA-Annandale), and Kirk Goolsby (NOVA-Annandale).

Pete and I are both products of the undergraduate geology program at William & Mary, he in 2001, and I in 1996. Here, Pete splints my simulated "broken leg":

(That's the way we are down at William & Mary. We help each other out.)

Do you lead field trips? Do you know what to do if a student breaks a leg? ...or goes into anaphylactic shock? ...or gets a stick through their eyeball? I'm sure glad I have answers to these questions now, and would recommend this (or more?) medical training to anyone who takes students more than 2 hours away from professional medical help. There's some serious @#%* that can go down in the backcountry. I feel like field trip leaders have an obligation to get trained in how to handle that @#%*.

Labels: conferences, field trips, grants

I'm also psyched about joining NAGT's ranks because they offer a series of grants. Getting small educational grants is my new hobby, so I'm looking forward to making some good stuff happen at NOVA with some sum from NAGT.

Labels: conferences, field trips, google, msse, teaching