DIRK WIERSMA / SCIENCE PHOTO LIBRARY DIRK WIERSMA / SCIENCE PHOTO LIBRARY
This small (actual height 150 mm) polished rock face shows intense deformation, both folding and faulting, in a metamorphic rock best labelled as an impure quartzite. Originally this has been a sedimentary deposit of quartz sand, alternating with clay and plant remains, deposited in a riverbed or the likes. In later geologic time these were deeply buried and the conditions of high pressure and temperature then in force altered the sand and clay beds into quartzite and laminae of carbon-rich schist and graphite. The intense forces at work brought about deformations in the rock known as foliation and microfolding as well as displacements by faulting. Eventually, uplift and erosion exposed this rock on the surface. Provenance unknown.
Model release not required. Property release not required.