Feeling a little overwhelmed at the office and home I sought out a working holiday doing a little fieldwork and writing at the University of California's Boyd Deep Canyon Reserve. The area has an interesting abundance of very large rock avalanches of unknown ages that I wished to map and sample. The image above shows one of the bouldery surfaces of one of these rock avalanches. The right horizon consists of a smooth dipping detachment fault surface separating felsic plutonic rocks (left skyline) in the hangingwall from the gneissic footwall rocks (right skyline). Interestingly the gneiss rocks only allow shallow drainages to form due to the low rainfall and high strength of the rock creating a shield-like surface. The granitic rocks above form relatively steep slopes that become isolated hills that in the right circumstances can collapse catastrophically sending a fast moving flow of jumbled rocks cascading several miles distance. All the rock avalanche I examined clearly are a delamination of the plutonic rocks on the weak, well oriented detachment fault surface.
An added bonus was a very green desert, complete with a wonderful wildflower display and highly active bugs and hummingbirds. It was a great little getaway.
No comments:
Post a Comment