Polished and slickenlined fault surface, Hurricane fault zone, Utah


I grabbed this example of a fault surface in 2008, when my students and I were mapping the details of a transfer zone along a part of the Hurricane fault just east of La Verkin.  I find that when non-geologists see this rock, and run their hands over it, they are astonished to learn that the polish and grooving was produced in Nature by faulting, and not ‘machined.’

Age & Formation
Canyon Member of the Moenkopi Formation of Triassic age, ~250 Ma.