Lake Tecopa
   HOME

TheInfoList



OR:

Lake Tecopa is a
former lake A former is an object, such as a template, Gauge block, gauge or cutting Die (manufacturing), die, which is used to form something such as a boat's Hull (watercraft), hull. Typically, a former gives shape to a structure that may have complex curv ...
in Inyo County, southern
California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
. It developed during the
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
and the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
within a
tectonic basin A structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat-lying strata. They are geological depressions, the inverse of domes. Elongated structural basins are also known as synclines. ...
close to the border with
Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
. Fed by the
Amargosa River The Amargosa River is an intermittent waterway, 185 miles (298 km) long, in southern Nevada and eastern California in the United States. It drains a high desert region, the Amargosa Valley in the Amargosa Desert northwest of Las Vegas, int ...
and some neighbouring washes, it eventually culminated to a surface area of around 186,000 years ago and left sediments. Afterwards, the Amargosa River cut a gorge out of the lake and into
Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...
with its
Lake Manly Lake Manly was a pluvial lake in Death Valley, California, covering much of Death Valley with a surface area of during the so-called "Blackwelder stand". Water levels varied through its history, and the chronology is further complicated by act ...
, draining the lake. The present-day towns of
Shoshone, California Shoshone is a census designated place (CDP) in Inyo County, California, United States. The population was 22 at the 2020 census, down from 31 at the 2010 census. The town was founded in 1910. Although small, it is notable as a southern gateway ...
and
Tecopa, California Tecopa (formerly Brownsville) is a census-designated place (CDP) in the Mojave Desert, in Inyo County, California, United States. Tecopa is located south-southeast of Shoshone, at an elevation of . The population was 150 at the 2010 census, u ...
lie within the basin of the former lake.


Hydrology

Lake Tecopa occupied the Tecopa Valley, a pear-shaped valley east of southern
Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...
, in Inyo County, California. The cities of Barstow, California and
Las Vegas, Nevada Las Vegas (; Spanish for "The Meadows"), often known simply as Vegas, is the 25th-most populous city in the United States, the most populous city in the state of Nevada, and the county seat of Clark County. The city anchors the Las Vegas ...
lie close to the lake basin. The lake itself had a roughly triangular shape with a northern, a southwestern and a southeastern corner, and at its highstand it covered about . Outcrops of lake sediments occupy a length of along the Amargosa River and are wide at their broadest. Its southern margin is not clear, given that the height of the sill to the China Ranch basin is undetermined. Several islands existed in Lake Tecopa. Of these, the largest was close to Tecopa, California, and two smaller ones were north of Shoshone, California. The shores of the lake featured marshes and
delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also re ...
s where Amargosa River or spring water entered the lake, as well as freshwater ponds where springs and streams flowed into Lake Tecopa. At the time of the Bishop Tuff eruption, Lake Tecopa was about deep. The waters of the lake were salty and had a high pH, inducing precipitation of
calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
in the northern part of the lake where the Amargosa River flowed into it. There is some indication that the centre of the lake was much more saline than its shores. Salt lakes generally form when a lake has no outlet, so
evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
concentrates salts in the lake water until the lake contains saltwater. The
Amargosa River The Amargosa River is an intermittent waterway, 185 miles (298 km) long, in southern Nevada and eastern California in the United States. It drains a high desert region, the Amargosa Valley in the Amargosa Desert northwest of Las Vegas, int ...
flowed into Lake Tecopa, which was the river's terminal lake. Most of the water in Lake Tecopa came from the Amargosa River and to a lesser degree from the washes that drain Chicago Valley and
Greenwater Valley Greenwater may refer to: * Green water, a maritime region * Greenwater, California * Greenwater, Washington Greenwater is a census-designated place (CDP) in the northwest United States in Pierce County, Washington. Southeast of Seattle, the pop ...
; the total size of its catchment was about and most of its water originated in Paiute Mesa,
Shoshone Mountains The Shoshone Mountains, in west central Nevada, make up one of the longest mountain ranges in the state. The range runs in a general north-south direction in Nye and Lander counties. The range has a length of about and a width of about with ...
, Timber Mountains and Yucca Mountains. The catchment of the Amargosa River above
Tecopa, California Tecopa (formerly Brownsville) is a census-designated place (CDP) in the Mojave Desert, in Inyo County, California, United States. Tecopa is located south-southeast of Shoshone, at an elevation of . The population was 150 at the 2010 census, u ...
is presently about . Later, after Lake Tecopa had disappeared, the river reached
Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...
and its
Lake Manly Lake Manly was a pluvial lake in Death Valley, California, covering much of Death Valley with a surface area of during the so-called "Blackwelder stand". Water levels varied through its history, and the chronology is further complicated by act ...
, dramatically increasing the supply of water to the latter. Presently, the river is largely
ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...
except where it is fed by springs.


Geography

The former lake basin is surrounded by various hills and mountain ranges, formed by rocks of Neoproterozoic to
Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...
age. Clockwise from north they are the
Resting Spring Range The Resting Spring Range is found in the eastern Mojave Desert of California near the Nevada state line in the United States. The range lies in a generally north–south direction to the west of the Nopah Range and southeast of the Amargosa Range ...
, the
Nopah Range The Nopah Range is a mountain range located in Inyo County, California, United States, near the eastern border with Nevada. Geography The mountain range lies east of the adjacent Resting Spring Range, the Owlshead Mountains and lower Death Valley ...
, the Sperry Hills, the
Ibex Hills The Ibex Hills are a mountain range in Inyo County, California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most po ...
, the
Greenwater Valley Greenwater may refer to: * Green water, a maritime region * Greenwater, California * Greenwater, Washington Greenwater is a census-designated place (CDP) in the northwest United States in Pierce County, Washington. Southeast of Seattle, the pop ...
and the Dublin Hills; together they enclose an area of about . The region belongs to the
Basin and Range Province The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...
of the western United States, where short ranges of mountains lie between plains. This geology consists of
normal fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
s which separate
graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...
s from horsts. It was affected by extensive tectonic activity in the past and may be still active in the present. Presently, the towns of
Shoshone, California Shoshone is a census designated place (CDP) in Inyo County, California, United States. The population was 22 at the 2020 census, down from 31 at the 2010 census. The town was founded in 1910. Although small, it is notable as a southern gateway ...
, Tecopa Hot Springs, California and
Tecopa, California Tecopa (formerly Brownsville) is a census-designated place (CDP) in the Mojave Desert, in Inyo County, California, United States. Tecopa is located south-southeast of Shoshone, at an elevation of . The population was 150 at the 2010 census, u ...
lie within the former bed of Lake Tecopa.
California State Route 127 State Route 127 (SR 127) is a state highway in the U.S. state of California that connects Interstate 15 in Baker to Nevada State Route 373 at the Nevada state line, passing near the eastern boundary of Death Valley National Park. The entire lengt ...
and California State Route 178 cross the lake basin from southwest to north and from west to east, respectively, while the Furnace Creek Road traverses it from northwest to southeast. The terrain of the region is characterized by badlands and rugged mountains with little vegetation away from springs. A number of
spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a ...
s form
oases In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment'ksar''with its surrounding feeding source, the palm grove, within a relational and circulatory nomadic system.” The location of oases has been of critical imp ...
in the area, including the locations of the three towns.


Climate

Presently, the area of Lake Tecopa is a hot, dry desert with most precipitation occurring during summer. In
Shoshone, California Shoshone is a census designated place (CDP) in Inyo County, California, United States. The population was 22 at the 2020 census, down from 31 at the 2010 census. The town was founded in 1910. Although small, it is notable as a southern gateway ...
average temperatures are and often exceed , with about of rainfall. Under present-day climates, evaporation is too high and precipitation too low to allow the formation of lakes in the area. 180,000 years before present, precipitation increased to and average temperatures decreased by , lifting the regional
water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. T ...
s.


Sediments

Various sediments were emplaced in the lake, including
adularia Orthoclase, or orthoclase feldspar (endmember formula K Al Si3 O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture," because its two cleavage planes are at right angles t ...
,
clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...
,
gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...
and
zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ・y where is either a metal ion or H+. These pos ...
s. Some of these formed when ash or sediments were progressively altered. The sediments take the form of calcareous, sandy, silty material or
mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...
. The sediments have undergone increasing amounts of diagenesis the closer they are to the basin center. Among the minerals found at various sites are
calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
,
gaylussite Gaylussite is a carbonate mineral, a hydrated sodium calcium carbonate, formula Na2Ca(CO3)2·5H2O. It occurs as translucent, vitreous white to grey to yellow monoclinic prismatic crystals. It is an unstable mineral which dehydrates in dry air and ...
,
halite Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...
and sepiolite. After the lake was breached, these deposits were deeply eroded and exposed, showing thicknesses exceeding . Mining for bentonite and pumicite took place from the 1920s to the 1950s.
Tufa Tufa is a variety of limestone formed when carbonate minerals precipitate out of water in unheated rivers or lakes. Geothermally heated hot springs sometimes produce similar (but less porous) carbonate deposits, which are known as travertine. ...
deposits are found within the lake and partly embedded in its sediments; they were generated from
carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...
precipitation within the lake, a process facilitated by the physical properties of the lake water. Many of these tufa deposits occur where fault-controlled
spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a ...
s discharged water into the lake. Several
tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they rem ...
layers have been identified, including the 2.003 million years old
Huckleberry Ridge Tuff The Huckleberry Ridge Tuff is a tuff formation created by the Huckleberry Ridge eruption that formed the Island Park Caldera that lies partially in Yellowstone National Park, Wyoming and stretches westward into Idaho into a region known as Island ...
, the 706,000 years old Bishop Tuff and the 602,000 years old Lava Creek Tuff as well as the 2, 1.2-0.8 million years old Glass Mountain tuffs. They form
tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
layers which are very conspicuous in the lake sediments.


Biology

A number of fossils were discovered in the sediments, including '' chara'',
diatoms A diatom (New Latin, Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group com ...
,
ostracods Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typical ...
,
snails A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastrop ...
and
vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
. Among
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s are '' Camelops'', ''
Equus Equus may refer to: * ''Equus'' (genus), a genus of animals including horses, donkeys and zebras * ''Equus'' (play), a play by Peter Shaffer * ''Equus'' (film), a film adaptation of the Peter Shaffer play * Equus (comics), a comic book characte ...
'',
mammoth A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks and, ...
and
muskrat The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...
. Footprints have been observed at the edges of the lake basin. Arcellacea and
foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...
have been found in lake sediments, including '' Bolivina goudkoffi'', ''
Centropyxis constricta ''Centropyxis'' is a genus of lobose testate amoebae (Amoebozoa Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondria ...
'', '' Lobatula lobatula'' and a few other, less widespread species. Foraminifera are mostly
ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
ic, and since Lake Tecopa was never connected to the ocean, they were most likely transported there by birds.


History

Lake Tecopa existed during the
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
and
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
. The basin of Lake Tecopa formed between 7 and 11 million years ago, but was then tectonically stable during the
Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
, although tectonic or
magmatic Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
activity may be occurring north of Shoshone. From about 5 million years ago to about 186,000 years before present, the lake developed inside the basin. Extensive faulting of lake deposits makes it difficult to reconstruct its history. About 2 million years ago, the
Amargosa Desert The Amargosa Desert is located in Nye County in western Nevada, United States, along the California–Nevada border, comprising the northeastern portion of the geographic Amargosa Valley, north of the Ash Meadows National Wildlife Refuge. The ...
began to drain into Lake Tecopa and a shallow lake existed back then, but between 1.6 and 0.9 million years ago the lake often became a
playa Playa (plural playas) may refer to: Landforms * Endorheic basin, also known as a sink, alkali flat or sabkha, a desert basin with no outlet which periodically fills with water to form a temporary lake * Dry lake, often called a ''playa'' in the so ...
. It is unlikely that the lake was ephemeral, however, given the presence of fossils in the lake sediments of foraminifera which do not tolerate such drying. Probably owing to uplift of 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 primarily ...
and expansion of the
catchment A drainage basin is an area of land where 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, the ...
, water levels at Lake Tecopa increased during the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
and reached highstands concurrently with other lakes in the
Great Basin The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
. The highest shoreline occurs at about elevation (subsequently tectonically deformed) about 186,000 years before present; it appears to coincide with the Eetza highstand of
Lake Lahontan Lake Lahontan was a large endorheic Pleistocene lake of modern northwestern Nevada that extended into northeastern California and southern Oregon. The area of the former lake is a large portion of the Great Basin that borders the Sacramento Rive ...
and
oxygen isotope stage Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data reflecting changes in temperature derived from data f ...
s 8, 7 and 6. Some doubts have been raised about this chronology, however. At some point after 579,000 years ago, a large slump occurred at the southwestern area of the lake, possibly triggered by an earthquake. Such earthquake activity is also responsible for the formation of
seismites {{Earthquakes Seismites are sedimentary beds and structures deformed by seismic shaking. The German paleontologist Adolf Seilacher first used the term in 1969 to describe earthquake-deformed layers. Today, the term is applied to both sedimentary ...
within the lake sediments. A number of faults criss-cross the area, several of them follow the borders of the Tecopa basin. Finally, there is evidence of
uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...
in parts of the southern basin. About 200,000 - 150,000 years before present, the lake overflowed and disappeared. Several different dates have been given for the time when the lake breached its boundaries, but it likely happened shortly after highstand. A long gorge was formed by the breaching event, which was triggered either by a river capture-like process or by overflow.
Subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...
in Death Valley may be ultimately responsible for the drainage change. It is possible that Lake Tecopa briefly reformed later, due to a temporary blockage of its outflow, and that at times the Amargosa River was blocked upstream from Lake Tecopa. The existence of the lake beds was described first by Levi F. Noble in 1926. In 1931,
Eliot Blackwelder Eliot Blackwelder (June 4, 1880 – January 14, 1969) was an American geologist who from 1922 to 1945 was head of the Stanford University department of geology. He served as president of the Geological Society of America in 1940 and of the Seismol ...
identified these lakebeds as the remnants of what he named Lake Tecopa. The area of the former lake has been the subject of numerous studies comprising various fields of geology but also biology, and an important target for field studies and
field trip A field trip or excursion is a journey by a group of people to a place away from their normal environment. When done for students, as it happens in several school systems, it is also known as school trip in the UK, Australia, New Zealand and ...
s. Research in the paleoclimatic conditions of the region has received impetus from the Yucca Mountain nuclear waste repository, since the future climate of the region is important in establishing how secure the nuclear waste would be.


References


Sources

* * * * * * * * {{Pleistocene Lakes and Seas
Tecopa Tecopa (formerly Brownsville) is a census-designated place (CDP) in the Mojave Desert, in Inyo County, California, United States. Tecopa is located south-southeast of Shoshone, at an elevation of . The population was 150 at the 2010 census, u ...
Natural history of Inyo County, California Pleistocene North America