Lake Manix

Lake Manix is a former lake fed by the Mojave River in the Mojave Desert of San Bernardino County, California.

Name

The name Lake Manix was bestowed upon the lake by J.P.Buwalda in 1913, who also named its fossil-bearing sediments Manix Beds. Thus, As of 2008 the study of the lake deposits is almost a century old.

Geography

Lake Manix was located 32–64 kilometres (20–40 mi) west of Barstow and Daggett. The town of Manix, California lies close to the lake bed.

Lake Manix had a trigonal shape, formed by a northwestern Coyote Basin, a south-southeastern Troy Basin and an eastern-northeastern Afton Basin. The latter basin is heavily dissected in comparison to the first two, and was formerly separated from the Cady Basin between Coyote Basin and Troy Basin by the Buwalda Ridge before the Mojave River eroded its way through it, possibly assisted by the Manix Fault trace. A bedrock sill at 540 metres (1,770 ft) separates the Coyote Basin from the rest of the lake basin. The total surface area of the lake was about 520–780 square kilometres (200–300 sq mi). Higher stands in the past may have reached until Yermo, California. Yermo together with Dunn and Newberry Springs are present day towns whose locations would have been close to the shore of or submerged beneath Lake Manix.

The upper threshold of the lake reached 543 metres (1,781 ft) above sea level; a shoreline at 549 metres (1,801 ft) was later shown to be an error of measurement, although some poorly recognizable higher shorelines at 547–558 metres (1,795–1,831 ft) have been found. These shorelines are marked by beach bars and wavecut scarps. Other landforms include alluvial fans, deltas, mudflats and their deposits. Part of the shorelines were buried by deposits transported by the Mojave River; these include large parts of a 557 metres (1,827 ft) high shoreline. One island potentially existed in the middle of the lake; at 558 metres (1,831 ft) it would have split in two and another island would have appeared as well.

The lake was surrounded by mountain chains, clockwise the Cronese Mountains, the Cave Mountains, the Cady Mountains, the Newberry Mountains, the Calico Mountains and the Alvord Mountains. These mountains are principally of volcanic origin and contributed sediments to Lake Manix. The whole region was subject to strong tectonically driven deformation from the Eastern California Shear Zone. A number of faults in the region show evidence of Holocene activity, including the Calico Fault, the Camp Rock Fault, the Dolores Lake Fault, the Pisgah Fault and the Manix Fault. This last fault probably contributed to the formation of the drainage by shearing rocks along its path.

The Mojave River entered the lake from the west. Afton Canyon drained the lake east towards Soda Lake, Silver Lake and eventually Death Valley. This draining cut 120 metres (390 ft) deep into the sediments of Lake Manix, removing about 2.815 cubic kilometres (0.675 cu mi) of material and depositing it below Afton Canyon.

The playas Coyote Lake and Troy Lake presently fill the homonymous basins of Lake Manix. In many places, wind and water driven erosion has removed deposits from Lake Manix and obscured shorelines. The present-day Interstate 40 and Interstate 15 cross the former lake bed of Lake Manix.

Lake Manix was influenced by earthquakes. Distorted sediments, soil liquefaction remnants and sand blows have been identified in drilling cores made in Lake Manix sediments. The whole lake basin is crossed by faults.

Hydrology

During the ice ages, a number of lakes filled in the Great Basin and the southwestern United States. These lake fillings were influenced by shifts in storm tracks caused by the Laurentide icesheet. Some interglacials also featured the growth of lakes. In the region, runoff is also influenced by the El Nino Southern Oscillation, the Northern Annular Mode and the Pacific Decadal Oscillation. Such lakes include Lake Babicora, Lake Bonneville, Lake Estancia, Lake Lahontan, Lake Manly, Lake Owens, Lake Panamint, Lake Russel and Lake Searles.

The Mojave River drained into Lake Manix, with the formation of the lake reflecting increased precipitation in the San Bernardino Mountains. Other local arroyos also drained into the lake. It has been estimated that runoff had to increase by a factor of about ten to form Lake Manix. Lake Manix contained over 1.6 cubic kilometres (0.38 cu mi) of water, possibly 3.2 square kilometres (1.2 sq mi). Water levels in the lake frequently fluctuated by 5–15 metres (16–49 ft). Formerly, it was the Mojave River's terminal lake.

Tufa formed within Lake Manix. Based on information gleamed from fossil ostracods, Lake Manix was a well mixed lake especially in summer; no thermocline developed in it. While the lake may have been warm during oxygen isotope stage 12 and possibly nourished from early summer runoff, after that point it was much colder with water temperatures not rising above 4 °C (39 °F). After oxygen isotope stage 5 the lake became warmer again. The environment of Lake Manix has been compared to shallow lakes in northern California behind the Cascades.

Lake Manix was not the only lake that formed on the Mojave River; Lake Mojave in the Silver Lake and Soda Lake basin was also formed by the river. Possibly, Lake Manix overflowed to that basin through Baxter Wash from a spillway south of the present-day Afton Canyon at an altitude of 544 metres (1,785 ft), but while it is reasonable to assume that earlier highstands were stabilized by overflow, there is no physical evidence in Baxter Wash for an overflow path there. Also the Mojave River together with the Amargosa River formed Lake Manly in Death Valley.

Water levels in Lake Manix appear to have reached peaks during both cold and warm stages of the Dansgaard-Oeschger events, with southward shift of storm activity and increased moisture supply triggering increased precipitation.

Biology

Bird species whose skeletons have been found in sediments of Lake Manix include the western grebe and the white pelican. Other bird skeletons found there were attributed to the species Aquila chrysaetos, Branta canadensis, Ciconia maltha, Erismatura jamaicensis, Grus, Nyroca valisineria, Pelecanus erythrorhynchos, Phalacrocorax auritus, Phoenicopterus copei and Phoenicopterus minutus. These are typical lake dwelling birds and have been found at Fossil Lake in Oregon.

The freshwater clam Anodonta californiensis existed in Lake Manix, as well as gastropods. Anodonta especially was probably very common in Lake Manix and other paleolakes considering the large shell deposits left by it. Fish species whose fossils have been found include the Mojave tui chub.

Ostracods also existed in the lake, including Limnocythere ceriotuberosa and other Limnocythere species. Subordinates include Candona species, Cypridopsis vidua, Heterocyphris incongruens, Limnocythere bradburyi, Limnocythere platyforma and Limnocythere robusta.

Diatoms which have been found at Lake Manix include Stephanodiscus species.

Climate

Present-day climates at the location of Lake Manix are dry and warm, with the mean temperature at Barstow reaching 17.7 °C (63.9 °F). Precipitation is scarce, 125–150 millimetres per year (0.156–0.187 in/Ms), and evaporation exceeds 2,000 millimetres per year (2.5 in/Ms).

History

Originally, the Mojave River flowed south before tectonic changes forced its course into the Mojave Desert, where it ended at Victorville and Harper Lake at first. About 500,000 years ago it reached the Cady Basin of Lake Manix, based on tephrochronological data of the Bishop Tuff. At first the river may have alternated between Harper Lake and Lake Manix. 190,000 years ago Afton Basin was integrated with the other three basins, as the river cut through the Buwalda Ridge. This breakthrough was probably a catastrophic flood, considering the chaotically bedded rocks formed by the breakthrough. Afton Basin had a bottom at an altitude of c. 460 metres (1,510 ft) before; as it was integrated into Lake Manix sedimentation progressively filled it.

Conflicting interpretations of the history of Lake Manix exist. One theory assumes three distinct highstands during the Pleistocene; they have been dated 33,500 - 30,500, 23,500 - 20,800 and 17,600 - 16,500 years ago. An alternative timeline assumes three highstands 40,000 - 35,000, 33,000 - 20,000 and 27,000 - 25,000 radiocarbon years. Clusters of shells in highstand deposits are dated 36,000 - 33,000 and 26,500 - 21,500 years before present. Other theories assume eight highstands and unstable lake levels between 45,000 and 25,000 years before present. Yet another theory assumes four highstands during oxygen isotope stage 6,4 and 2.

The lake existed at least until 14,230 ± 1,325 years before present. Lake Manix drained when the Afton Canyon formed, possibly around 13,800 years before present. This drainage was probably quick and removed Lake Manix within a short time, perhaps as little as ten hours. The draining probably contributing to the "Lake Mojave II" highstand of Lake Mojave. After the initial catastrophic cutting, a slower incision further deepened the Afton Canyon. Alternative theories assume a much slower formation of the Afton Canyon outlet, based on the presence of several terraces and possible recessional landforms. The formation of this path was probably aided by the Manix Fault, which had left easily eroded sediments. The Mojave River may have drained into the Coyote Basin even after the formation of Afton Canyon, until headward erosion cut off that basin from the river flow. Sediments transported through Afton Canyon during the event and later have buried the landscape beneath Afton Canyon, potentially also contributing sand to the development of the Kelso Dunes.

Presently, almost all runoff of the Mojave River comes from the San Bernardino Mountains, and ground infiltration and water diversions mean the river ends in the Victorville area; only the biggest floods can reach all the way to Soda Lake.

Archeology

Lithic artifacts have been found at the shorelines of Lake Manix. Some are of late Pleistocene age. Such artifacts include bifaces, disks, flakes and hammerstones which were grouped as the "Lake Manix Industry". Their supposedly pre-Clovis origin was questioned for a number of reasons. Dates obtained on the desert varnish they were embedded in yielded ages of 400-32,000 years before present, indicating that these items have varying origins and cannot be considered part of one grouping.

See also

• List of lakes in California
• Manix Formation

References

Sources

• Bamforth, Douglas B.; Dorn, Ronald D. (1988). "On the nature and antiquity of the Manix Lake Industry" (PDF). Journal of California and Great Basin Anthropology. 10 (2). Retrieved 6 March 2017. {{cite journal}}: Invalid |ref=harv (help)
• Berger, Rainer; Meek, Norman (1992-01-01). "Radiocarbon Dating of Anodonta in the Mojave River Basin". Radiocarbon. 34 (3): 578–584. doi:10.1017/S0033822200063852. ISSN 0033-8222. {{cite journal}}: Invalid |ref=harv (help)
• Clarke, M. L.; Richardson, C. A.; Rendell, H. M. (1995-01-01). "Luminescence dating of mojave desert sands". Quaternary Science Reviews. 14: 783–789. doi:10.1016/0277-3791(95)00051-8. ISSN 0277-3791. {{cite journal}}: Invalid |ref=harv (help)
• Howard, Hildegarde (1955). "Fossil Birds from Manix Lake, California" (PDF). pubs.usgs.gov/pp. {{cite web}}: Invalid |ref=harv (help)
• Meek, Norman (1989-01-01). "Geomorphic and hydrologic implications of the rapid incision of Afton Canyon, Mojave Desert, California". Geology. 17 (1): 7–10. doi:10.1130/0091-7613(1989)0172.3.CO;2. ISSN 0091-7613. {{cite journal}}: Invalid |ref=harv (help)
• Reheis, Marith C.; Bright, Jordon; Lund, Steve P.; Miller, David M.; Skipp, Gary; Fleck, Robert J. (2012-12-01). "A half-million-year record of paleoclimate from the Lake Manix Core, Mojave Desert, California". Palaeogeography, Palaeoclimatology, Palaeoecology. 365–366: 11–37. doi:10.1016/j.palaeo.2012.09.002. {{cite journal}}: Invalid |ref=harv (help)
• Reheis, Marith C.; Miller, David M.; Redwine, Joanna L. (October 2007). "USGS Open-File Report 2007-1281: Quaternary Stratigraphy, Drainage-Basin Development, and Geomorphology of the Lake Manix Basin, Mojave Desert–Guidebook for Fall Field Trip, Friends of the Pleistocene, Pacific Cell". pubs.usgs.gov. Retrieved 2017-03-06. {{cite web}}: Invalid |ref=harv (help)
• Reheis, Marith C.; Miller, David M. (2010). "Environments of nearshore lacustrine deposition in the Pleistocene Lake Manix basin, south-central California" (PDF). Geosciences and Environmental Change Science Center, USGS. {{cite web}}: Invalid |ref=harv (help)
• Reheis, Marith C.; Redwine, Joanna L. (2008-01-01). "Lake Manix shorelines and Afton Canyon terraces: Implications for incision of Afton Canyon". Geological Society of America Special Papers. 439: 227–259. doi:10.1130/2008.2439(10). ISSN 0072-1077. {{cite journal}}: Invalid |ref=harv (help)
• Reheis, Marith C.; Redwine, Joanna R.; Wan, Elmira; McGeehin, John P.; VanSistine, D. Paco (2014). "Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California". Scientific Investigations Map. doi:10.3133/sim3312. {{cite journal}}: Invalid |ref=harv (help)

Bibliography

• Philip Stoffer (14 January 2004). "The Mojave River and Associated Lakes" (.html). Desert Landforms and Surface Processes in the Mojave National Preserve and Vicinity. Open-File Report 2004-1007. USGS, US Department of the Interior. Retrieved 2009-09-12.
• USGS (13 January 2004). "Mojave National Preserve: Soda Lake". Geology in the National Parks. U.S. Department of the Interior. Archived from the original on 2007-03-11. Retrieved 2009-09-12.
• Philip Stoffer (14 January 2004). "Changing Climates and Ancient Lakes" (.html). Desert Landforms and Surface Processes in the Mojave National Preserve and Vicinity. Open-File Report 2004-1007. USGS, US Department of the Interior. Retrieved 2009-09-12.