Tuesday, September 10, 2013

Geo 365: Sept. 10, Day 253: Kerr Notch

Kerr (pronounced "car") Notch is a terrific example of a beheaded glacial valley; the classic "U" shape is clearly visible. I don't know whether this valley was occupied by ice when the great cataclysm occurred, though it seems doubtful to me that it was. This would have been on a SSE-facing slope, well after the end of the ice ages, so it seems most likely to me that the feature was carved during the Pleistocene, and was simply a stream at the time of the great eruption. This spot is also the head of Sand Creek. Farther down the valley, ignimbrite deposits have been carved into "The Pinnacles," which was my selection for "sexy geology" a couple years ago. (The associated Wedge is here.)

Photo unmodified. August 18, 2011. FlashEarth location.

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