Okay, back to Patagonia for this week's photo. This isn't in my specific field area, but very close to it and in the same formation. What's really cool about this area is the presence of clastic dikes ...

Igneous rocks are rebels. Sedimentary rocks follow straight-forward rules—they are deposited in horizontal layers, with the oldest sediments on the bottom. Igneous rocks can do what they want. Molten ...