A few of my favorite pet rocks
For the 4th edition of The Accretionary Wedge blog carnival, which is hosted over at goodSchist, we are showing off our favorite pet rocks (or “deskcrops” as coined by Thermochronic).
The first shot below is an “overview” shot of three of my favorite deskcrops (or, more correctly in this case, bookcasecrops).
1. Permian Evaporites of the Castile Formation
Stopping along Highway 62/180 in between Guadalupe Mtns National Park and Carlsbad Caverns is a favorite for geology field trips of any kind. At this location, you are not in any national park and can smash and grab as much of this rock as you want. The photo below is a close-up of these beautifully-varved evaporites (alternating calcite and anhydrite, and some halite in there too).
2. Permian Turbidite
Also from the Permian Delaware Basin of west Texas and New Mexico, this sample was given to me by my master’s advisor. It is from the Cherry Canyon Formation and nicely shows the “a”, “b” and “c” divisions of a Bouma turbidite sequence. The “a” division is a the base and is normally-graded and structureless (just the very bottom of this particular deskcrop). This grades upwards into the plane-laminated “b” division. And, finally, the top of the deskcrop is the ripple-laminated “c” division. What’s particularly nice about this sample is how exquisite the ripple forms are preserved. One of my favorites!
3. Xenoliths from Kilbourne Hole
I didn’t even realize until now that all of these deskcrops are from the same region. I picked up some beautiful xenoliths from this maar volcano just last September. The locale is a little tricky to find (it’s a hole in the desert), but there are still lots of beautiful olivine/pyroxene xenoliths like this one to find if you can find it.
Thanks to Chris over at goodSchist for hosting…go check it out.