Solitario-Sierra Madera-Odessa Meteor Crater
Perhaps I missed a post or two, but there may be a bit of confusion. I have visited all three. The Solitario (which seems to have started this) is in the Big Bend, mostly on Big Bend Ranch State Park. About 9 miles across, it is neither a caldera nor an meteor crater. It's a volcanic feature, though (a huge laccolith that blew it's top). The park sells an excellent geologic discussion of it, and the rest of the geology of the park. Odessa Meteor Crater . A meteor impact crater(astroblem). It looks like a crater and is about 550 feet across. It is geologically very young - about 63,000 years old. Bill describes it well. Sierra Madra - another astroblem on the north side of the Glass Mountains in southern Pecos County. It is larger and older than the Odessa crater, younger than 100 my (Cretaceous or younger). The center bounced back up and created a jumble of broken rock that is more resistant to erosion than its surroundings and now forms a central peak which sticks up about 800 feet. You can see it from US 385 north of Marathon. It's been drilled down to undisturbed rocks below it. DirtDoc
