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1 January 2018
New year’s day is the time I tally up my accumulated bird species seen in my yard on the forested slope of Massanutten Mountain. This is my sixth such annual list. Here are the previous iterations: 2012 (39 species) 2013 (52 species) 2014 (58 species) 2015 (65 species) 2016 (59 species) Here we go, in chronological order of first appearance in our yard: Red-tailed hawk Red-bellied woodpecker Mourning dove Raven …
28 November 2017
I believe in tinkering with my teaching, and reflecting on the new approaches to see if I think they’re worth keeping or not. One of the topics I teach is the geologic history of Virginia. I do this because it’s essential knowledge to put the students’ upcoming field trip in context, but it’s also a nice example of how geologic techniques can be applied to understand the history of a …
27 October 2017
What does it mean for a vein to be “quantankerous?” Well, to start with, it’s quartz. Second, it has to be disagreeable or cantankerous. This vein, seen in meta-arkose of the Catoctin Formation near the summit of the Blue Ridge at Rockfish Gap (not Afton Mountain), is such a quantankerous individual: You’ll notice its “S” shape, which might imply top-to-the-left kinematics. But just down the outcrop is this set of …
18 October 2017
The 2017 Virginia Geological Field Conference had a heavy arkose infusion. Meet some of these feldspar-rich Neoproterozoic sediments of the Lynchburg Group.
11 August 2017
For the Friday fold, Callan digs out images of Eagle Rock, Virginia, well aged in his digital archive for a decade!
15 April 2017
My son and I hiked Compton Peak in Shenandoah National Park this morning, and saw these two lovely examples of xenoliths. The example above is small, but it shows clearly the difference between the coarse, felsic basement rock (Mesoproterozoic granitoid, comprising the xenolith) and the surrounding fine-grained dark green metabasalt of the Catoctin Formation (Neoproterozoic). Here’s another, bigger example: These two Blue Ridge examples both illustrate the principle of relative …
27 March 2017
Explore a dozen photos highlighting the structural geology of an outcrop of limestone and shale near Lexington, Virginia. Cleavage refraction, overturned beds, boudinage, folds, and even a small fossil – we’ve got something for everyone. Bring the whole family!
27 February 2017
A new outcrop in Fort Valley shows Devonian fossil-rich mudrocks overprinted by a tectonic cleavage imparted during Pangaea’s birth throes.
25 February 2017
Some enormous concretions are encountered in a shale quarry in the central Fort Valley. Concretions like these are typical of the Devonian-aged Millboro Formation.