Bishop Tuff

Two layers of the Bishop Tuff: lower layer was from ashfall, upper layer was from the main pyroclastic flow.
Rocks from the Bishop tuff, uncompressed with pumice on left; compressed with fiamme on right.
See also: Long Valley Caldera

The Bishop Tuff is a welded tuff that formed 767100 ± 900 years ago as a rhyolitic pyroclastic flow during the eruption that created the Long Valley Caldera.[1] Large outcrops of the tuff are located in Inyo and Mono Counties, California, United States.

Contents

Modern exposure

Southern margin of the pyroclastic flow looking west towards the Sierra Nevada Mountains. The Lower Owens River is seen along the edge of the flow, and the town of Bishop, California at left.
Map of the Long Valley Caldera, with Bishop Tuff outlined.

The Bishop Tuff caps a volcanic plateau in the northern Owens Valley. The tableland formation is located east of U.S. Route 395 and west of the Nevada stateline, sitting northwest of Bishop and southeast of Crowley Lake and Mammoth Lakes. Another part of the flow is south of Mono Lake, and surrounding the Mono-Inyo Craters.

Deposits of Bishop Tuff in this area cover nearly 2,200-square-kilometer (850 sq mi), and range in thickness from 150-meter (490 ft) to 200-meter (660 ft).

The Owens River cut through the volcanic plateau, creating the Owens River Gorge.

See also

References

  1. ^ Crowley, J.L.; B. Schoene, and S.A. Bowring (December 2007). "U-Pb dating of zircon in the Bishop Tuff at the millennial scale". Geology 35 (12): 1123–1126. doi:10.1130/G24017A.1. http://geology.gsapubs.org/content/35/12/1123.abstract?sid=a0f68c6b-fb94-4070-9171-9835eb71b9b7. Retrieved 26 September 2010. 

External links