Every Rock Has A Story - Bishop Tuff

The Bishop tuff – formed from the fusion of a slurry of hot gas, rhyolite ash, pumice and glass resulting from a tremendous explosive volcanic eruption 760,000 years ago. The eruption created a massive 16 by 32 km depression called the Long Valley caldera, east of the central Sierra Nevada Mts. near Owens Valley California. Over a 6-day period the eruption generated a 300 square km blanket of volcanic rock 150 to 200 M thick, stretching all the way to Nebraska. There has not been a major eruption at the LV caldera for over 50,000 yrs, but it is carefully monitored by the USGS.