Lake Modoc is a former lake in

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

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, in the location of present-day

Upper Klamath Lake Upper Klamath Lake (sometimes called Klamath Lake) ( Klamath: ?ews, "lake") is a large, shallow freshwater lake east of the Cascade Range in south-central Oregon in the United States. The largest body of fresh water by surface area in Oregon, it ...

Lower Klamath Lake Lower Klamath Lake is a lake in Siskiyou County, California. At one time it was connected to Upper Klamath Lake. It currently is used to hold overflow water for Klamath Project irrigation uses. The lake is in Northern California, near the borde ...

and

Tule Lake Tule Lake ( ) is an intermittent lake covering an area of , long and across, in northeastern Siskiyou County and northwestern Modoc County in California, along the border with Oregon. Geography Tule Lake is fed by the Lost River. The ele ...

. It existed during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene 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 ...

epochs, its formation probably influenced by volcanism and faulting. The bed of the former lake had plentiful resources for early humans, and today it is used for agriculture.

Background

It has been known for over a century that large lakes previously existed in the

Western United States The Western United States (also called the American West, the Western States, the Far West, the Western territories, and the West) is List of regions of the United States, census regions United States Census Bureau. As American settlement i ...

, most notably

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 ...

Lake Lahontan Lake Lahontan was a large endorheic prehistoric lake during the Pleistocene that occupied modern northwestern Nevada and extended into northeastern California and southern Oregon. The area of the former lake is a large portion of the Great Basi ...

and

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

Lake Bonneville Lake Bonneville was the largest Late Pleistocene paleolake in the Great Basin of western North America. It was a pluvial lake that formed in response to an increase in precipitation and a decrease in evaporation as a result of cooler temperatur ...

. Such lakes also formed in

eastern Oregon Eastern Oregon is a region of the U.S. state of Oregon. It is not an officially recognized geographic entity; thus, the boundaries of the region vary according to context. It is sometimes understood to include only the eight easternmost countie ...

, where present-day

Malheur Lake Malheur Lake ( ) is one of the lakes in the Malheur National Wildlife Refuge in Harney County, Oregon, Harney County in the U.S. state of Oregon. Located about southeast of Burns, Oregon, Burns, the lake is marsh fed by the Donner und Blitzen ...

and Goose Lake are remnants of former

pluvial lake A pluvial lake is a body of water that accumulated in a basin because of a greater moisture availability resulting from changes in temperature and/or precipitation. These intervals of greater moisture availability are not always contemporaneous ...

s. Lake Modoc was so named by Samuel N. Dicken, professor of geography at the

University of Oregon The University of Oregon (UO, U of O or Oregon) is a Public university, public research university in Eugene, Oregon, United States. Founded in 1876, the university is organized into nine colleges and schools and offers 420 undergraduate and gra ...

. The region of Lake Modoc was first described during the early and mid-19th century.

The lake

Lake Modoc was a pluvial lake that existed 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 ...

in basins formed by faulting and volcanism. It covered a length of from south of Tule Lake in California to near present-day

Fort Klamath Fort Klamath was a military outpost near the western end of the Oregon Trail, between Crater Lake National Park and Upper Klamath Lake in Klamath County, Oregon, United States. The Fort Klamath Site, about a mile southeast of the present communi ...

in Oregon, its waters reaching an elevation of about above sea level and covering an area of about with a highly irregular shape. Several islands formed in the lake, such as the Klamath Hills, present-day Miller Hill close to

Klamath Falls Klamath Falls ( ) is a city in, and the county seat of, Klamath County, Oregon, United States. The city was originally called ''Linkville'' when George Nurse founded the town in 1867. It was named after the Link River, on whose falls the city wa ...

and Turkey Hill close to Malin. The shoreline of Lake Modoc is well visible close to

Hydrology

Unlike other pluvial lakes, Lake Modoc had a steady inflow of surface water, owing to its proximity to snow- and glacier-covered mountains of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

. Its watershed extended over present-day

Modoc Modoc may refer to: Ethnic groups *Modoc people, a Native American/First Nations people ** Modoc language ** Modoc Nation, a federally recognized tribe of Modoc * Modoc War, the last armed resistance of the Modoc people in 1873 *The "Modocs", ri ...

and Siskiyou counties (both in California), and

Jackson Jackson may refer to: Places Australia * Jackson, Queensland, a town in the Maranoa Region * Jackson North, Queensland, a locality in the Maranoa Region * Jackson South, Queensland, a locality in the Maranoa Region * Jackson oil field in Durham, ...

Klamath Klamath may refer to: Ethnic groups *Klamath people, a Native American people of California and Oregon **Klamath Tribes, a federally recognized group of tribes in Oregon *Klamath language, spoken by the Klamath people Places in the United States * ...

and

Lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

counties (all in Oregon), including the Williamson River, Sprague River and Lost River. Cinder,

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...

and

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

from the Cascades filled the lake. Lake Modoc also featured an outflow, at first to the south before a

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

blocked it, although seepage continued from there to this day. Presently, the

Klamath River The Klamath River (Karuk language, Karuk: ''Ishkêesh'', Klamath language, Klamath: ''Koke'', Yurok language, Yurok: ''Hehlkeek 'We-Roy'') is a long river in southern Oregon and northern California. Beginning near Klamath Falls, Oregon, Klama ...

drains the area. Given that the basin at present cannot hold a lake the size of Lake Modoc, it is likely that its formation and demise was influenced by the existence of outlets.

History

Lake Modoc was probably formed by geologic processes such as faulting or by the

Medicine Lake Volcano Medicine Lake Volcano is a large shield volcano in northeastern California about northeast of Mount Shasta. The volcano is located in a zone of east–west crustal extension east of the main axis of the Cascade Volcanic Arc and the Cascade Ra ...

blocking a former southward-draining outlet. The lake appears to have existed during the Pleistocene and late Pliocene, with some lake deposits estimated to be at least 3 million years old. During marine oxygen isotope stage 4, Lake Modoc was deep and cold. Volcanic eruptions formed

tuff cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

s in the lake, such as at The Peninsula. Water levels began to decrease as the Pleistocene ended, as the climate became drier and the outlet to the Klamath River lower. The former lake floor is nearly level, and the shoreline is almost unwarped. Today,

and

remain from Lake Modoc; Upper Klamath Lake is the largest present-day lake in Oregon by surface area. The floor of the drying lake featured deep soils and abundant vegetation, water and wildlife; thus it was quickly populated by humans who migrated there over 3,000 years ago. The former lake bed is now used as cropland, and agriculture is the most prevalent human land use in the region. Part of the southern shoreline has been covered by

s, and geologic processes have continued into the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

; the Glass Mountain lava flow was emplaced about 1,000 years ago, and some Holocene lava flows have been faulted.

References

Works cited

* * {{DEFAULTSORT:Modoc, Lake Pleistocene North America Pliocene North America Pliocene California Klamath River Lakes of California Lakes of Oregon Geology of Oregon Lakes of Modoc County, California Lakes of Siskiyou County, California Lakes of Jackson County, Oregon Lakes of Lake County, Oregon Lakes of Klamath County, Oregon Former lakes of the United States