Mono Basin

Geologically the basin is a structural basin that is bordered to the west by the frontal fault of the Sierra Nevada. The basin is part of the Walker Lane, an area where much of the deformation between the North American Plate and the Pacific Plate occurs.{{cite web|url=http://geomaps.wr.usgs.gov/fed_lands/task5.html|title=Geology of Federal Lands in the Eastern Sierra Region, southwestern Great Basin|first=Angela|last=Jayko|work=Geology of Parks and Federal Lands of the Southwest|publisher=USGS|access-date=2013-02-14}}

The basin was formed by geological forces over the last five million years: basin and range crustal stretching and associated volcanism and faulting at the base of the Sierra Nevada.{{Cite book|title=Geology of the Mono Basin|last=Tierney|first=Timothy|year=2000|publisher=Kutsavi Press, Mono Lake Committee|location=Lee Vining, California|isbn=0-939716-08-9|edition=revised|pages=45–46}}{{rp|45}}

File:Mono Lake sat zoomed.jpg

From 4.5 to 2.6 million years ago, large volumes of basalt were extruded around what is now Cowtrack Mountain (east and south of Mono Basin); eventually covering {{convert|300|sqmi|km2}} and reaching a maximum thickness of {{convert|600|ft|m}}.{{rp|45}} Later volcanism in the area occurred 3.8 million to 250,000 years ago.{{rp|46}} This activity was northwest of Mono Basin and included the formation of Aurora Crater, Beauty Peak, Cedar Hill (later an island in the highest stands of Mono Lake), and Mount Hicks.{{fact|date=May 2023}}

Lake Russell was the prehistoric predecessor to Mono Lake, during the Pleistocene. Its shoreline reached the modern-day elevation of {{convert|2280|m|ft}}, about {{convert|330|m|ft|-2}} higher than the present-day lake. As of 1.6 million years ago, Lake Russell discharged to the northeast, into the Walker River drainage. After the Long Valley Caldera eruption 760,000 years ago, Lake Russell discharged into Adobe Lake to the southeast, then into the Owens River, and eventually into Lake Manly in Death Valley.{{cite journal|year=2002|title=Drainage reversals in Mono Basin during the late Pliocene and Pleistocene|doi=10.1130/0016-7606(2002)114<0991:DRIMBD>2.0.CO;2|first1=MC|last1=Reheis|first2=S|last2=Stine|first3=AM|last3=Sarna-Wojcicki|journal=Geological Society of America Bulletin|volume=114 |issue=8 |page=991 |bibcode=2002GSAB..114..991R }} Prominent shore lines of Lake Russell, called strandlines by geologists, can be seen west of Mono Lake.{{cite web|url=http://volcanoes.usgs.gov/volcanoes/long_valley/long_valley_sub_page_16.html|title=Mono Lake|work=Long Valley Caldera Field Guide|publisher=USGS|access-date=2015-01-13|archive-url=https://web.archive.org/web/20141229114402/http://volcanoes.usgs.gov/volcanoes/long_valley/long_valley_sub_page_16.html|archive-date=2014-12-29|url-status=live}}

Mono Basin is currently geologically active. Volcanic activity is related to the Mono-Inyo Craters: the most recent eruption occurred 350 years ago, resulting in the formation of Paoha Island.{{cite web|url=https://www.usgs.gov/volcanoes/mono-inyo-craters|title=Mono-Inyo Craters|publisher=USGS|access-date=2023-05-31}} Panum Crater is an example of a combined rhyolite dome and cinder cone.{{cite web|url=https://www.usgs.gov/volcanoes/long-valley-caldera/long-valley-caldera-field-guide-panum-crater|title=Long Valley Caldera Field Guide - Panum Crater|publisher=USGS|access-date=2023-05-09}}

• Mono Basin National Scenic Area

{{Reflist}}

{{Refbegin}}

• {{cite book|last=Hill|first=Mary|title=Geology of the Sierra Nevada|publisher=University of California Press|edition=2nd|year=2006|series=California Natural History Guides|volume=80}}
• {{Cite book|title=Geology of the Mono Basin|last=Tierney|first=Timothy|year=2000|publisher=Kutsavi Press, Mono Lake Committee|location=Lee Vining, California|isbn=0-939716-08-9|edition=revised}}

{{Refend}}

• [http://www.monolake.org/ Mono Lake Committee]

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Category:Landforms of the Sierra Nevada (United States)

Category:Valleys of Mono County, California

Category:Valleys of California