Mono Craters
Posted by: 
brwhiz
N 37° 52.869 W 119° 06.408
11S E 314720 N 4194720
This Inyo National Forest sign explaining the significance of volcanic activity in the vicinity of Mono Lake is located in a turnout on the southeast side of California Highway 158 about 1.1 miles southwest of the junction with US Highway 395.
Waymark Code: WMGFBC
Location: California, United States
Date Posted: 02/25/2013
Views: 9
Mono Craters
The mono craters are a chain of volcanic mountains. The highest stands 2700 feet above the valley floor. When they began to form late in the ice age, this basin was covered by ancient Lake Russell. Mono Lake is a remnant of that lake. Initially in their formation, a series of explosions created high, bowl-shaped cones of pumice (volcanic froth). Later, great domes of obsidian (volcanic glass) arose in the cones. The obsidian usually overflowed the pumice rims and advanced onto the plains as steep-sided jumbles of boulders. These obsidian domes and flows are dominant features of the craters.
Pumice, blasted out and carried by the winds, covers many square miles of ancient lake sediments and glacial debris to a depth of several feet.
Inyo National Forest