RESTING SPRING
RANGE
A traditional field trip stop in southeastern
California's Resting Spring Range is a nice roadcut of obsidian. The jet
black band of rock shown in the pic above is the obsidian. It is highly
fractured, and only relatively small pieces can be collected. The rocks
above & below the obsidian are rhyolitic welded tuffs. These
volcanics are Tertiary in age.
Locality:
northern side of Rt. 178, just west of the crest of the Resting Spring Range,
east of Shoshone, southeastern California, USA. GPS of cut: 35º
59.830' N, 116º 13.187' W. See
map. Note: this black band of obsidian even shows up well on Google
Earth.
The photo above shows a nice subvertical fault in a
Tertiary-aged succession of volcanics.