21 July 2017
My friend Ander Sundell at the College of Western Idaho is the source of today’s Friday fold. It’s from somewhere in Sardinia, and I think you’ll find it visually striking:
The rocks here are Silurian phyllites generated from mudstones that were deposited on the floor of the rheic ocean basin. The color and grain size variation do an excellent job highlighting compositional layering. They were deformed during the Variscan Orogen, which the last phase of a composite mountain belt that ultimately formed Pangea. This photo shows an excellent example of axial planar cleavage.
Guest submissions of Friday folds are always welcome. Thanks for contributing, Ander!