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Sunday, 31 January 2021

Groom Lake, Nevada United States

Groom Lake is a dry Salt Lake in Nevada. It is used for runways of the Nellis Bombing Range Test Site Airport Part of the Area 51 USAF installation. The lake lies at an elevation of 4,409 ft and it is about 3.7 miles from north to south and three miles from east to west at its widest point and is about 11.3 miles in circumference. Located within the namesake Groom Lake Valley portion of the Tonopah Basin, the lake is 25 mi south of Rachel, Nevada.

The nearest publicly accessible vantage point is Tikaboo Peak, twenty-six miles to the east. There were two closer vantage points, dubbed "Freedom Ridge" and "White Sides", but they were closed to public access in 1995 to prevent people from taking pictures of the installation. In popular culture, Groom Lake is a location in the zombie’s maps "Moon" and "Classified" in the Call of Duty: Black Ops franchise.

 

Groom Lake lead and silver were discovered in the southern part of the Groom Range in 1864. The English Groome Lead Mines Limited company financed the Conception Mines in the 1870s. That is giving the district its name (close mines included Maria, Willow, and White Lake). The mining claims in Groom were acquired by J. B. Osborne and partners and patented in 1876, and Osborne's son acquired the interests in the 1890s. The claims were proved in 1916 when two companies began working their mines; that work continued until 1918 and resuming after World War II until the early 1950s. Mineral production within the quadrangle has been principally leading and silver from the Groom mine in the Groom Range and silver from the Kelly mine located in the Pint- water Range south of Groom.

 

Papoose Lake is a dry lake bed located in Lincoln County, Nevada, U.S.[1] The lake lies within the plot of land referred to as the Groom Lake facility (also known as Area 51) and is a restricted area. The lake is located a few miles southwest of the Groom Lake facility nestled adjacent to the Papoose Range.

 

Geological Setting

 

Rocks within the Pahranagat Range Quadrangle range in age from Precambrian through Tertiary.  Precambrian rocks crop out mainly in the western portion of the quadrangle and consist of shale, siltstone, and silty limestone of the Johnnie Formation and quartzite, siltstone. The thin beds of limestone of the Sterling Quartzite in the Half-pint and Groom Ranges. Rocks in the Papoose Range to be Cambrian age. Maybe Precambrian and correlate with those in the Groom Range to the north. Paieozoic quartzite, shale, and carbonate units are present in most of the ranges within the quadrangle but the most extensive Paleozoic exposures are in the Pahranagat, Desert, and Pint water Ranges.

 

Tertiary volcanic units, including andesite and basalt flows, welded ash-flow tuffs. The intervocalic sedimentary units cover portions of the Hiko, Pahranagat, Groom, and Half-pint Ranges. The only intrusive rocks mapped within the quadrangle are porphyritic rhyodacite dikes, sills, and stocks in and adjacent to Bald Mountain in the central Groom Range. The major regional structural features exposed within the quadrangle are thrust faults and northeast-striking strike-slip faults. There were at least two periods of thrust faulting, Laramide and probably Cretaceous or Eocene.

 

One-third of the area of pre-tertiary outcrops in the quadrangle is underlain by major thrust faults. The most prominent structural feature of the area is the Pahranagat shear zone, composed of northeast-striking faults with apparent strike-slip movement. Faults related to this regional structure pass through the Southeastern district at the north end of the Pint water Range. The south end of the Pahranagat Range, and possibly between the Groom, Papoose, and Desert Ranges, have defined a caldron centered on Bald Mountain in the Groom Range. Volcanic rocks in the Groom Range and the adjacent Desert Range may have originated from this caldron.