Friday Field Foto #29: Western Escarpment of the Guadalupe Mountains, west Texas

I did not take this photograph below…it was taken by my master’s degree adviser from a helicopter.

This is where I am right now…well, right now I’m on my way here. This is the western escarpment of the Guadalupe Mountains in west Texas. The prominent light-colored cliff-forming rocks at the top is the famous Permian Capitan Formation. In fact, the highest peak there is called Guadalupe Peak and is the highest point in Texas (8,749 ft). The Capitan is a fossiliferous limestone reef succession. The regional dip of the strata is to the east (to the right on the photo); a few tens of km away this limestone package dives into the subsurface and is the rocks in which Carlsbad Caverns is located. If you have the chance to go, you should do it.

The rocks underlying the Capitan Reef, although not as photogenic and striking, are incredibly interesting geologically. This escarpment is essentially a cross section of an exhumed Permian shelf margin. It’s difficult to explain in words, so I make a few annotations on the photo below showing what I’m talking about.

We are on a student-run field trip right now and one of the days is to hike halfway up in the area where the basin-restricted wedge pinches out against the underlying shelf margin.

You can find out more details about the geology and fantastic stratigraphic relationships exposed here, here, or here.

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