Saturday, August 23, 2014

Geo 730: August 23, Day 600: Boulder Creek Boulder

Boulder Creek is a tributary to Quartzville Creek, just a bit upstream from the quarry. I don't have any photos of "the pyrite stop" (Yes, another one) up the road there, but I'll post a link to a nice 360 by 360 panorama sooner or later. I've always presumed Boulder Creek was named for this giant block at the confluence, and no one has ever told me differently. It's not easy to get a sense of scale here, but I'd estimate those two tree trunks to the boulder's lower left are in the range of 18-24 inches. The rock is humongous. That actually presents a bit of a problem; at that size, it's not readily apparent how it could have been transported at all, let alone without getting smashed into flinders. My best guess is that it was entrained into a debris flow up the tributary sometime over the last few hundred to thousand years. This would have provided both a transporting agent and cushioning from crushing impacts. And my guess about the timing would provide enough time for floods and steady erosion to remove most of the smaller fragments associated with that hypothetical debris flow. If you look just a bit to the right of the cross hairs, across the creek from the road, in the FlashEarth view, this behemoth is readily visible.

Photo unaltered. July 7, 2012. FlashEarth Location.

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