Thursday, September 1, 2011

Desert RATS - Day 5 - Geology field trip

This year the VAPoR team has brought its own geologist, Jim Rice. Jim is here only for a few days and amongst his duties was observing the crew in their efforts of clean sampling (more about that in a next post) and organically clean collecting some more samples for VAPoR. 

After we ran our second sample of the day he took us out for a field trip first to SP Crater and then to Sunset Crater (for more information about volcanoes, check out this site).

What we learned: 

1) the oldest (visible) layer in this region is the Kaibab Limestone - Early Permian, or 299-270 million years old:
Kaibab Limestone with Jim for scale

2) the layer on top of that is the Moenkopi Sandstone - Early (and possibly Middle) Triassic, 240 million years old:
Moenkopi Sandstone with Inge's foot (size 37/6.5) for size. The ripples are leftovers from a shallow sea that was present at the deposition of this formation. (240 million year old flow ripples!!)

3) Black Point Lava Flow (our test site) is about 2 million years old. 

4) SP crater is a text book example of a cinder cone volcano and is estimated to be ~71,000 year old. SP is short for Shit Pot, what is what this volcano looked like according to one of the earlier owners of land that included the volcano (C.J. Babbit, 1880s). Obviously, in the geology textbooks only the abbreviation is used.

SP Crater

SP Crater, outflow channel, Danny for scale

5) Sunset Crater is the youngest cinder cone volcano around here, about 1000 years old: 
Sunset Crater, Jim and Inge for scale

Around Sunset Crater there are some interesting volcanic features, such as squeeze ups - cooling lava being squeezed through a thickening, solidifying lava crust -  and hornitos (little ovens) - hot, still liquid lava spattering up through a thickening, solidifying lava crust!

Squeeze-Up with Danny for scale


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