Geologist Peter Thompson photographed these rocks in East Thetford, Vermont. What is the rock type, and what would you call structures like this?
Answer
This is slate that has been deformed by kink folds. The thinly layered rocks were placed under stress by tectonic forces, in this case related to a nearby Mesozoic fault, which formed during the breakup of Pangea.
This week’s contest winner was Walter Trzcienski