A little east of the point where Highway 178 turns east and heads out of Death Valley, we stopped to look at an exposure of the Amargosa Chaos. This rock unit is a megabreccia that contains up to house-size blocks of almost exclusively Kingston Range Granite, a late Miocene intrusive unit. The formation originated during the latest Miocene as a rock-avalanche deposit that fell off a steep, west-facing mountain front composed of Kingston Range Granite. Observations on the character of the deposit indicate that it could not have slid more than 10 km from it's source in the proto-Kingston Range, which today is far to the southeast. To bring the deposit to it's present location requires latest Miocene-Pliocene extension of about 30 km along the Amargosa detachment system.
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