2 November 2012
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.