Geo 730: August 3, Day 580: Peripheral Clay

After a few miles of these "peripheral clay patches," as I'll dub them, the Quartzville tour enters a stretch with minimal alteration- there are a few highly altered spots, such as the one I'll be featuring next, but by and large the rocks are fairly fresh. As I mentioned in The August first post, the effects of the hydrothermal alteration in this district are very patchy and discontinuous, especially in the outer portions. Toward the center, it's a more consistent, multi-generational quartz breccia, with multiple episodes of fracturing and silicification, but even there, just a few steps can take you from one rock type to something that appears very different.

Photo unmodified. June 19, 2012. FlashEarth location (uncertain, but looks right, and close).