Friday, March 15, 2013

Geo 365: March 15, Day 74: More Pluvial Features at Fort Rock

Yesterday's view was shot looking approximately east; today's is turned to approximately southwest, looking toward the opposite end of the amphitheater. Again, there is an excellent example of a wave-cut notch at the foot of the cliff, and at least one distinct step a bit below that- for scale, I'm guessing that step is about the height of a typical adult, maybe 5-6 feet. There is also a hint of fossil shorelines on the low hill in the mid-distance; those are more distinct in the full-size view.

The fact that the "fort" at Fort Rock is open to approximately the south-southeast suggests that during pluvial times, at least, that is the direction from which prevailing winds came most often and most strongly. Thus wave erosion was most effective against that sector of the tuff ring. However, even in the areas where the edifice is largely removed, bare surfaces of the eroded rock provide plenty of opportunity to see structural clues as to what once existed overhead.

Photo unmodified. August 20, 2011. FlashEarth Location.

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