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Mono Lake Volcanic Field

Aerial view from above Mono Lake towards the west-southwest.
Aerial view from above Mono Lake, California towards the west-southwest.The declining water level of the lake is clearly seen by the parallel lines and white-colored lake deposits ringing the shore. The diversion of fresh-water inflow to the city of Los Angeles and evaporation has led to the decline in water level at a rate of about 1 m per year. The snow-covered mountains in the background are the Sierra Nevada. (Credit: Miller, C. D. Public domain.)

The Mono Lake volcanic field, east of Yosemite National Park and north of the Mono Craters, consists of vents within Mono Lake and on its north shore. The most topographically prominent feature, Black Point, is an initially sublacustral (below lake level) basaltic cone that rises above the northwest shore and was formed about 13,300 years ago when Mono Lake was higher. Holocene rhyodacitic lava domes and flows form Negit and parts of Paoha islands off the northern shore and center of the lake, respectively. The most recent eruptive activity in the Long Valley to Mono Lake region took place sometime around 200-300 years ago, when lake-bottom sediments forming much of Paoha Island were uplifted by intrusion of a rhyolitic dome that never reached the surface. This type of dome is called a cryptodome. Spectacular tufa towers line the shores of Mono Lake.