1 June 2012

Friday fold: Hoh Hoh Hoh

Posted by Callan Bentley

Another guest submission for the Friday fold – this is becoming a major trend!

Peter Selkin‘s student Rick Schwartz loaned us this one. Peter describes the outcrop this way:

The rocks here are Miocene turbidites of the Hoh lithic assemblage (sometimes called the “Hoh Terrane”) exposed at Beach #4 on the Pacific coast of the Olympic Peninsula. The train of folds here appears to be related to propagation of the fault near the bottom of the photo. Looking at the folds in detail, it’s pretty clear that the shale layers have flowed while the more competent sandstones buckled or, in some cases, broke. Classic chevron folding stuff. Nearby, there are a whole mess of steeply-dipping, overturned beds; I never checked to see if the beds here are upside down.