2 November 2012
Friday fold: dinner plate
Posted by Callan
Last week, I got the chance to show my new colleague John Singleton, the freshly-installed structural geologist at George Mason University, around the Billy Goat Trail in Potomac, Maryland. We spied a nice fold in a dinner-plate-sized slab that had broken off parallel to the profile plane of the fold:
It’s a nice example of a “similar” fold (where the layers are thinned on the limbs and thickened at the hinge area). This fold likely formed due to orogenic activity accompanying the docking of a volcanic archipelago with “eastern” North America in the late Ordovician period of geologic time.
Happy Friday!
Callan Bentley is an assistant professor of geology at Northern Virginia Community College in Annandale, Virginia. He is particularly interested in structural geology and the evolution of the Appalachian mountain belt. Callan draws cartoons and writes for EARTH magazine. He lives in the Fort Valley of Virginia.
