Slaty turbidites, Chilkat State Park, SE Alaska.

These beautiful turbidites are exposed along the shore of Chilkat State Park,near Haines. Not only is the setting amazing --that's Chilkat Inlet and the Chilkat Range in the background-- but they're also very instructive. Note how the cleavage exists only in the shaly layers, but it curves as it approaches the sandy layers. This "cleavage refraction" occurs because the finer-grained shales take up more strain than the coarser sandstone. And the sandstone is typically graded --the very first photo in this collection gives a close-up view of two graded beds.

But to heck with all that... it's a wonderful place just to wander around!


On to the next photo: Glacial cirque, Glacier National Park, Montana.
Back to the last photo: Aerial view of the Wallowa Mountains, Oregon

Back to Ten favorite geology photos from 2015