Wednesday, July 9, 2014

Geo 730: July 2, Day 548: Folds Plus Minor Reverse Faults

A bit up the road from yesterday's photo, the disturbed nature of the rocks in this cut are more apparent. There looks to be a minor reverse fault behind the wire and down the slope from the oak in the right middle near the top, and another that looks incipient to the left of that same tree. This is Flournoy Formation, which in this area is normally gently tilted, but not deformed to anywhere near the degree we see here. This is a restricted, and as far as I know, unique, occurrence of highly deformed rocks of this area and age. (Older, Klamath Province rocks can be extremely deformed, but these are of Coast Range affinity.) It doesn't appear to be related to tectonism. A possible explanation is that it was a large, but localized, slump before the rocks had been buried too deeply. As I mentioned yesterday, it seems that the now-accepted term for that sort of thing is a mass transport deposit.

Photo unmodified. March 9, 2012. FlashEarth location.

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