The Mono Basin is an

endorheic An endorheic basin ( ; also endoreic basin and endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water (e.g. rivers and oceans); instead, the water drainage flows into permanent ...

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

located east of

Yosemite National Park Yosemite National Park ( ) is a List of national parks of the United States, national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The p ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

. It is bordered to the west by the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

, to the east by the Cowtrack Mountains, to the north by the Bodie Hills, and to the south by the north ridge of the

Long Valley Caldera Long Valley Caldera is a Depression (geology), depression in eastern California that is adjacent to Mammoth Mountain. The valley is one of the Earth's largest calderas, measuring about long (east-west), wide (north-south), and up to deep. Lo ...

.Mono Basin, Mono County, California
/ref> Estimates of the size of the basin range from 634 to 801 square miles, and the basin's elevation ranges from around 6,380 feet (level of

Mono Lake Mono Lake ( ) is a Salt lake, saline soda lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in an endorheic basin. The lack of an outlet causes Hypersaline lake, high levels of salts to accumulate in the lake ...

as of 1986) to 13,061 feet atop

Mount Dana Mount Dana is a mountain in the U.S. state of California. Its summit marks the eastern boundary of Yosemite National Park and the western boundary of the Ansel Adams Wilderness. At an elevation of , it is the second highest mountain in Yosemite ...

near the

Sierra Crest The Sierra Crest is a roughly generally north-to-south ridge, ridgeline that demarcates the broad west and narrow east slopes of the Sierra Nevada and that extends as far east as the Sierra's escarpment, topographic front (e.g., Diamond Mountain ...

. Notable features in the basin include

and the Mono-Inyo Craters, as well as the town of Lee Vining.

Geology

Geologically the basin is a

structural basin A structural basin is a large-scale structural geology, structural formation of rock stratum, strata formed by tectonics, tectonic warping (Fold (geology), folding) of previously flat-lying strata into a syncline fold. They are geological dep ...

that is bordered to the west by the frontal fault of the Sierra Nevada. The basin is part of the

Walker Lane The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a major left lateral, or sinistral, strike-slip fault. The north-northwest end of the Walker ...

, an area where much of the deformation between the North American Plate and the Pacific Plate occurs. The basin was formed by geological forces over the last five million years: basin and range crustal stretching and associated

volcanism Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

and faulting at the base of the

From 4.5 to 2.6 million years ago, large volumes of

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

were extruded around what is now Cowtrack Mountain (east and south of Mono Basin); eventually covering and reaching a maximum thickness of . Later volcanism in the area occurred 3.8 million to 250,000 years ago. 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. Lake Russell was the prehistoric predecessor to Mono Lake, during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. Its shoreline reached the modern-day elevation of , about 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

eruption 760,000 years ago, Lake Russell discharged into Adobe Lake to the southeast, then into the Owens River, and eventually into

Lake Manly Lake Manly was a pluvial lake in Death Valley, California. It forms occasionally in Badwater Basin after heavy rainfall, but at its maximum extent during the so-called "Blackwelder stand," ending approximately 120,000 years before present, the ...

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. It is thought to be the Highest temperature recorded on Earth, hottest place on Earth during summer. Death Valley's Badwat ...

. Prominent shore lines of Lake Russell, called strandlines by geologists, can be seen west of Mono Lake. 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. Panum Crater is an example of a combined

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

and

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

Footnotes

References

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External links

Mono Lake Committee
{{Authority control Landforms of the Sierra Nevada (United States) Valleys of Mono County, California Valleys of California

Geology

See also

Footnotes

References

External links