Thursday, May 31, 2007

Friday Field Foto #19: Trough cross-bedding

I'm puttin' these up a day early because we are actually going on a 4-day field trip starting tomorrow. Yay!This photo is a shot looking down on the bedding plane of cross-bedded sandstone. The pencil is in the area between two migrating arcuate dunes. If you're lucky enough to get a bedding plane exposure of cross-stratified deposits you can use them as paleocurrent indicators. In this case, the pencil is pointing downstream.
This is in a shallow-marine unit of the Cretaceous in central Utah.

All Friday Field Fotos are taken by me unless otherwise noted.