Friday Field Foto #99: Angular unconformity in Darwin Canyon, California
This week’s Friday Field Foto is from an area just west of Death Valley called Darwin Canyon. As you can see, there is a sharp, angular contact between two sedimentary formations — an angular unconformity.
Note person in lower right for scale.
When I took this photograph I didn’t have any specific knowledge of this geology because we were driving between stops. But 2 minutes on the google machine uncovered this fantastic web resource — Death Valley Geology: A Field Guide and Virtual Tour by Steven G. Spear from Palomar College.
The information for this angular unconformity is here and this is what they have to say about it:
The layers below the unconformity are the lower Permian Darwin Canyon formation seen at the folds up-canyon. The layers on top are Triassic marine deposits (and may correlate to similar age strata in Butte Valley). The angular discordance of the unconformity is about 20o. The age of this unconformity has been quite well dated. The youngest fossils in the beds from under the unconformity are Wolfcampian fusilinids of the Panamint Springs member of the Darwin Canyon formation. The oldest fossils from the layers above the unconformity are Guadelupian (Capitanian) brachiopods and mollusks.