I got to Pittsburgh around 1:30pm yesterday, which meant I had several free hours before the opening reception for new Fine Fellows. I took a bunch of photos of the exhibits there, but my traveling laptop doesn’t have the image processing software that I usually employ to resize these things, so for now I’ll just share this one. It’s a sandstone from South Dakota, age unknown, which shows beautiful parallel small faults. Viewed from this angle, the top has moved to the right relative to the bottom. I like the little lens-shaped zone in the middle where the strain is more pronounced. Reminds me of something I’ve seen elsewhere. You can click through to make it much bigger.
I think that the rock may be from Calico Canyon, which is near Buffalo Gap, SD. The rock is the Fall River (Dakota) Sandstone, which is Cretaceous.