You are browsing the archive for March 2019 - Mountain Beltway.
29 March 2019
Friday fold: Plunging Purisima
AGU’s Centennial year is also the 35th anniversary of the publication of Clyde Wahrhaftig’s unique field guide to the geology of San Francisco. A team of geologists is updating “A Streetcar to Subduction” for a modern digital audience, and recently did some California field work to visit key sites. Check out one of them here with the Friday fold, as we visit a plunging syncline in the Purisima Formation on the coast near San Mateo.
27 March 2019
Timefulness, by Marcia Bjornerud
[Note: this book review was scheduled to run in the July 2019 issue of EARTH magazine, but with the announcement two weeks ago that EARTH was being shuttered, I was notified that nothing contributors or freelancers had written scheduled for after April 2019 would be published, and the rights were returned to me. While that’s disappointing, it frees me up to publish it here instead. Enjoy!] _____________________________________________ Geology is a …
25 March 2019
The End, by Phil Torres
I’ve been fortunate lately to get to meet and interact with Phil Torres, independent scholar of existential risks. At my prompting, Phil came to a GSW meeting where Peter Brannen was talking about mass extinctions, and later he came to my class to talk to my Historical Geology students at NOVA about risks humanity faces. I figured it was about time I read his books, and now I can report …
22 March 2019
Friday fauxld: concentric weathering rinds
Here’s a deceptive Friday “faux”ld I saw last week on the South Page Valley Road whilst learning about the Martinsburg Formation outcrops there: Looks like an isoclinal fold in this slab of siltstone, but the curvy lines are just concentric weathering rinds. Not a real fold at all! I hope everything you see this weekend is more straightforward and less deceiving. Happy Friday!
20 March 2019
The Dinosaur Artist, by Paige Williams
A book review of Paige Williams’ “The Dinosaur Artist,” a tale of international trade in dinosaur skeletons.
18 March 2019
New discoveries in the Martinsburg Formation
A virtual field trip to examine some deepwater clastic sediments shed off the first phase of Appalachian mountain building, and deformed in the third phase. It’s a lovely day for a field trip to the late Ordovician!
15 March 2019
Friday folds: two more from Oman and Chuck Bailey
Friday is that special day of the week where we take a break from our hurried lives and gaze longingly at great photos of folded rocks in exotic corners of the world. Today, we return to Oman, and we say, “Oh, man!”
8 March 2019
Friday fold: Dent de Morcles
The Friday fold is a recumbent anticline/syncline pair, deforming the K/Pg boundary in the Swiss Alps, as photographed from the air by Bernhard Edmaier.
1 March 2019
Friday fold: Gold Harbour, South Georgia
Near Antarctica, South Georgia Island is a good place to find glaciers and penguins. And, as it turns out: massive recumbent folds! Let’s take a look.
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.