Thursday, August 8, 2013

Geo 365: August 8, Day 220: Simpson Reef

An oblique view of Simpson Reef, between Shore Acres and Cape Arago State Parks, near Charleston, Oregon. I had recalled this as a plunging anticline/syncline pair, and it more or less is. But as is so often the case, it's a little more complicated than I thought- there's a substantial fault cutting through as well. I've just spent an inexcusable amount of time tracking down the article (3.9 Mb pdf) that first clarified for me to the geology of the area. We visited and mapped the north cove of Cape Arago, visible in the aerial photo below, in our structural geology class, with Bob Yeats, lo these many years past. I found the Ore Bin Piece shortly afterward, and things kinda sorta started making sense. The following two illustrations are from the article linked above.
 The vantage point from which the leading photo was taken is labeled "Sealion Viewpoint" on the sketch map below, which also clarifies the structure. The viewpoint is indeed a good place to watch pinnepeds during calving season- late June through early August. Hint: bring binoculars. But when I stop here, it's more often to look at the geology.
Photo unmodified. March 8, 2012. FlashEarth location.

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