9 March 2014
I just wanted to let readers know that posting will be light this week, as I’m down in Texas running my field exchange course with Joshua Villalobos of El Paso Community College. Joshua’s supplying 12 students, and so am I. Together with talented colleagues, we’re aiming to give these students, many of whom hail from traditionally-underrepresented groups within the geosciences, a world-class field experience that will take them from the Border to the Beltway. We have a week in West Texas and New Mexico this week, and then we are reuniting in May in Virginia to examine mid-Atlantic geology. The program is funded by a generous grant from the National Science Foundation as an experiment to see if we can recruit a more diverse suite of geoscientists by facilitating a top-notch field experience early in their educations.
Anyhow – I’ve got a Friday fold scheduled for the end of the week, but don’t expect anything before then. Bye!
7 March 2014
Happy Friday! Here’s a beautiful folded obsidian sample, replete with conchoidal fractures, on display outside the geology department at Arizona State University in Tempe, where I was last week:
6 March 2014
The Wallbridge Unconformity is a surface of stratigraphic hiatus or erosion between the depositional influence of the Tippecanoe and Kaskaskia epeiric seas. After Alan Pitts and I located ourselves in the Oriskany Sandstone (terminal Tippecanoe stratum), we looked stratigraphically above the quartz sandstone for the overlying unit, which should be the Needmore Formation shale (beginning of the Kaskaskia sequence). Indeed, the quartz sandstone was overlain by a black shale at the site:
This road cut is on the south side of the highway, facing north. Hence, it was in deep shade when we visited in late afternoon. Uncharacteristically, I see I failed to include a sense of scale in that photo, but the peaklike sandstone outcrop at left is probably about 7 meters tall.
A better exposure can be seen on the north side of the road, where it’s not only sunny, but the contact is more discernible.
I remembered to include a sense of scale for this shot. Thanks, Alan!
Here’s what strikes me about this exposure: the contact between quartz arenite below and black shale above does not appear to be abrupt or erosional, like I would expect a disconformity to appear. Instead, there are gradually thinner and thinner sandstone beds, and thicker and thicker shale beds. Let’s zoom in:
Fundamentally, this looks transitional (conformable). It doesn’t look like an unconformity. But it’s supposed to be one. So what gives?
5 March 2014
Today, a few more photos from the field trip last month to Corridor H, the fine new superhighway with so little traffic out in eastern West Virginia.
Our antepenultimate stop of the day was at an outcrop we inferred should hold the Oriskany Sandstone, a Devonian quartz arenite that lies stratigraphically above the Helderberg Group limestones and below the Needmore Shale. We were using Lynn Fichter’s indispensible stratigraphic column for our explorations, and while some of the Oriskany looked like what I expected it to, there was also a greater diversity of the unit than we expected: dark gray color in places (rather than the sugary white I recalled as classic Oriskany), conglomerates, etc.
We did find a bunch of brachiopod fossils, though, and that is something I associate with outcrops of the Oriskany such as those on Sandy Mile Road near Sideling Hill. Let’s see some…
Articulate brachiopod shells in cross-section:
Here’s another brachipod, a huge one with a relatively flat morphology, a strophomenid, I reckon:
Zoom in on the fine radiating costae on the shell:
I pried off some of the overlying sandstone to reveal more of this lovely beast:
And, just for variety’s sake, here’s a gastropod (snail) we found at the site, too:
4 March 2014
I recently read God’s Harvard, by Washington Post reporter Hanna Rosin. It’s a profile of the people and philosophy behind Patrick Henry College, a private Christian college located not too far from me, in Purcellville, Virginia. PHC is an Evangelical place that strives to serve its homeschooled matriculating freshmen with a sense of worldliness and mastery of the liberal arts, so that by the time they graduate, they are equipped to influence the country. They want to aggressively move the U.S. toward more conservative and Christian principles. When George W. Bush was President, an extraordinary number of White House interns (~7%) came from this one small school, a proportion akin to Georgetown University or other traditional centers of the academic elite. Let’s clarify what we mean by small: 300-350 students, and a couple dozen full-time faculty.
So there’s something distinctive about this place – in spite of its diminutive size, it has (or at least, had) a disproportionate involvement in the power structure of the United States of America. It’s not “just another Bible college.” That special something was what drew author Rosin in, and it appears that she was given extraordinary access to the place, profiling its students in detail, select members of its faculty, and most particularly, its chancellor, Michael Farris. Farris founded and ran the Home School Legal Defense Association prior to his venture into higher education, and he also once ran (when I was in college) for lieutenant governor of the Commonwealth of Virginia. Portrayed by Rosin, Farris comes off as driven so acutely to advance his mission that he undermines his own efforts, like a cannon so powerful that it knocks itself askew once it starts firing. (Military analogies abound in discussions of PHC, as most of its adherents see themselves fighting a mighty cultural war.)
The book charts the school from its founding through to a major kerfuffle when the least zealous faculty were fired or quit due to internecine conflict with Farris. He wanted them to be more explicitly Christian at each possible moment, and the faculty wanted to teach as they saw fit. It was a classic case of academic freedom. Some of the students were inspired by some of these faculty, and even staged a “Dead Poets Society” sort of protest when it all fell apart in 2006. The school survived. PHC continues to accept and graduate students, and presumably the remaining faculty toe the line better than their ex-colleagues managed.
PHC was in the news last month, incidentally, when a piece by Kiera Feldman in the New Republic documented a pattern of suppressing reporting of incidents of sexual assault at the college. I didn’t read the book because of that article, but having them both cross my radar in the same month deepens my sense of attention towards this interesting place. I’m interested in PHC because it’s higher education, it’s in my own state (like Liberty University), and it’s a distinctive manifestation of the ongoing cultural conflict between U.S. subpopulations. PHC is a creationist institution, to be clear. Everyone who teaches or learns there must subscribe to a statement of faith. Coming from a background of unfettered intellectualism, wherein conclusions are results rather than preconditions, I find it hard to imagine such a thing – but I guess that’s where books like Rosin’s come in, shedding some light on what would otherwise be mysterious.
Anyhow, I’m glad to know more about this singular place as a result of reading this book.
3 March 2014
A week ago today, I was in Tempe, Arizona, at Arizona State University, for a workshop on broadening participation (increasing diversity) in the geosciences. One of the neat things about ASU as a setting for this meeting is their enormous meteorite collection. I was particularly taken with the display of material from the extraordinary Chelyabinsk meteor detonation that occurred last year.
ASU has pieces of glass from windows that were shattered by the shock wave…
…as well as fragments of the meteorite itself:
Pretty awesome. Meteorite impacts are far less common today than they were early in the history of our solar system. When they do occur, they can delight, amaze, awe, and potentially even kill. A big enough one could wipe out a huge number of people. Chelyabinsk was a close one: people were hurt, but no one died. These fragments of (a) the early solar system and (b) human architecture are tangible physical reminders we would do well to heed.
2 March 2014
We visited the Philip Carter Winery this weekend with family. Baxter and I were pleased to see outcrops of charnockite scattered over the property (located in the middle of the Blue Ridge geologic province).
As any 18-month-old will tell you, charnockite is a pyroxene-bearing granitoid. It’s a distinctive and common rock type in Virginia’s Proterozoic basement complex. Here’s a close-up:
The dark green is pyroxene. The white is plagioclase feldspar. The kid shows signs of interest in rocks.
28 February 2014
For the Friday fold, let’s journey back to the Silurian, as exposed in the limestones of that age that were deformed during Alleghanian mountain-building (Pennsylvanian and Permian), and exposed along Corridor H in eastern West Virginia.
Some buckling (cuspate-lobate form) seen in that one…
A little pop-up with hinge collapse:
And, finally, as a digestif, consider this little morsel:
That’s a bite-sized Friday fold.
Have a good weekend!
27 February 2014
Over the past 2 weeks, I’ve been sharing some images here from a field trip the previous week to Corridor H in eastern West Virginia. I love this road, but I guess it’s fair for me to point out that sometimes in the middle of winter, this is what the outcrops look like:
…Yep. Next road-cut, please.
26 February 2014
More images for you today from my field trip a few weeks ago to West Virginia’s bizarro highway Corridor H, a quiet place built for roaring traffic. Its multistory roadcuts are fresh and profound; they offer the most incredible views into the mid-to-late-Paleozoic surface of Earth… and the creatures that lived there.
In the Devonian period, the Helderberg Group of limestones was deposited. It’s full of interesting fossils, the remains or traces of ancient lifeforms:
Here’s a solitary coral:
And now, a slab of thinly veiled crinoid columnals:
And lastly, a suite of ostracodes, odd arthropods (relatives of crabs and ants and trilobites and scorpions) with a clam-like shell enclosing their leggy bodies. They look like beans: