15 May 2012

Diabase dike in diabase

Posted by Callan Bentley

Seen in rip-rap on the side of Naked Creek, a week ago yesterday:

This boulder is exotic to its current location. It is typical of medium- and coarser-grained diabase from the Culpeper Basin, a Triassic rift valley east of the Blue Ridge. The main minerals are plagioclase (light-colored) and pyroxene (dark colored).