Mojave Desert

Important sources of boron are ore rasorite (kernite) and tincal (borax ore). Both of these ores are found in the Mojave Desert. Tincal is the most important source of boron from the Mojave. Extensive borax deposits are also found in Turkey. 

Boron is mined as borax and kernite, Na2B407-xH20, with x = 10 and 4, respectively. Large deposits from ancient hot springs are found in volcanic regions, such as the Mojave Desert region of California. In the extraction process, the ore is converted into boron oxide with acid and then reduced with magnesium to an impure brown, amorphous form of boron ... 

Alley RB, Mayewski PA, Sowers T, Stuiver M, Taylor KC, Clark PU (1997) Holocene climatic instability A prominent, widespread event 8200 yr ago. Geology 25 483-486 Amelin Y, Zaitsev AN (2002) Precise geochronology of phoscorites and carbonatites The critical role of U-series disequilibrium in age interpretations. Geochim Cosmochim Acta 66 2399-2419 Amundson RG, Chadwick OA, Sowers JM, Doner HE (1988) Relationship between climate and vegetation and the stable carbon isotope chemistry of soils in the eastern Mojave Desert, Nevada. Ouat Res 29 245-254... 

The United States and Turkey are the world s largest producers of boron.1 Economically important sources are from the ores rasorite (kernite) and tincal, which are both found in the Mojave Desert of California, with borax being the most important source there. The famous 20-Mule-Team Borax, now a part of chemistry folklore, originates from the time when teams of 20 mules used to haul colemanite from Furnace Creek in Death Valley 166 miles south to Mojave. Elemental boron in its impure form can be obtained by the reduction of the oxide B203 by magnesium, and in the pure form by the reduction of BC13 by hydrogen on hot filaments.1... 

A 12-year-old boy develops uncontrollable panic while camping with his parents in the Mojave Desert. 

Yonkers et al, have tested the ozone susceptibility of 15 species of annuals common to the Mojave Desert just north and east of the Los Angeles basin (and San Bernardino Mountains). Compared with the susceptible pinto bean plants included in the experiment with ozone at 0.35 ppm, Plantago sp., Cercidium sp., and Prosopsis sp. were also sensitive. Further interpretation of these results is complicated by the influences of plant age and pre-exposure conditions. 

Izbicki JA, BaU JW, Bullen TD, Sutley S J (2008) Chromium, chromium isotopes and selected trace elements. Western Mojave Desert, USA, Appl Geochemistry 23 1325-1352 Jaffres JB, Shields GA, Wallmann K (2007) The oxygen isotope evolution of seawater a critical review of a long-standing controversy and an improved geological water cycle model for the past 3,4 billion years. Earth Sci Rev 83 83-122... 

Reible, D.J. Ouimette, J.R. Shair, F.H., Visibility Degra-tion Associated with Atmospheric Transport into the California Mojave Desert, accepted by Atmospheric Environment, 1981. 

Basgall, M. E. Hall, M. C. Archaeological Investigations at Goldstone (CA-SBR-2348) A Middle Holocene Occupation Complex in the North Central Mojave Desert, Far Western Anthropological Research Group Davis, CA, 1994... 

California Western Mojave Desert Groundwater Ball and Izbicki (2003)... 

Ball, J.W. and Izbicki, J.A. (2003) Geochemical relations among arsenic, chromium, and other trace elements in ground water underlying the Sheep Creek fan, western Mojave Desert, California. Abstracts with Programs-Geological Society of America, 35(6), 565. 

Figure 4. Depth profiles of iil l) (PDB) versus soil depth, from three sites in the Mojave Desert, (a) SM-3 (1990 masl), (b) SM-2b (1550 masl), and (c) PaM-1 (300 masl), all from Quade et al. (1989a).

Figure 7. 518Osc (PDB) of soil carbonate collected from 50 cm soil depth versus elevation (masl) from Holocene-age soils in the Mojave Desert (from Quade et al. 1989a). Soil carbonate collected on both limestone and non-limestone parent materials show die same approximate decrease with elevation of —5.5 %o/km. Soil profile values are the same as in Figure 4. The line denotes the 5 0 (PDB) predicted from local values from 32 rainfall collection sites in the Mojave Desert (518Omw (SMOW) = -0.0013...

Figure 8. The residuals calculated from Figure 7 plotted against mean annual rainfall for each Mojave Desert site.

A landmark project in California is the Mojave Solar Park, which is to be built in the Mojave Desert. When complete, the 6,000 acre will use 1.2 million parabolic mirrors and 317 miles of vacuum tubing to capture the sun s heat, generating 553 megawatts of solar power, enough to support 400,000 homes in northern and central California. The park uses technology developed by Solel Solar Systems of Israel. PG E, a major California utility, will be the major customer when the system comes on line in 2011. 

Considering that the electricity used by the United States is about 4.5 x 1012 kWh/yr (15.35Q), if this amount of energy was to be produced by solar farms in the arid southwestern regions (the area of the Mojave Desert alone is 15,000 mi2), the area required to generate 1 Q at a yearly insolation is 2,250 kWh/m2/yr and with a collector efficiency of 20% is 2,250/3,000 x 488 x 15.35 = 5,618 km2 or 2,194 mi2. Therefore, 14.6% of the Mojave Desert would need to be covered to meet the total electric energy requirement of the United States. 

The present cost of a 25 kW, 944 ft2 stand-alone prototype unit is about 150,000. This price is likely to drop as production volume rises. Stirling Energy Systems, Inc., is operating a six-dish test unit at Sandia National Laboratories and has contracts for full-size power plants. Their construction started in 2008 and will be completed in 2012. A 500 mW plant will be built at Victorville, California, in the Mojave Desert for Southern California Edison. This construction is estimated to take 3-4 years. The plant will consist of 20,000 dishes over a 4,500 acre area. Another 300 mW plant will also be built at Imperial Valley, Calexico, California, for San Diego Gas and Electric on an area of 2,000 acres. 

Today, the largest solar power plant in the United States is the 22-year-old thermal plant in California s Mojave Desert, which has a combined total capacity of 354 mW. At Kramer Junction, California, nine solar power plants, each 30 mW or larger, have been in operation for two decades. The yearly insolation in the area is 2,940 kWh/m2. Plant efficiencies range from 10 to 17%, and their capital costs range from 2,500 to 3,500 per kWp The cost of generated electricity from these plants drops as their size increases, and ranges from 10 to 17 /kWh. 

If the solar power plants are built in locations such as the Mojave Desert or Sahara, the land cost might not be excessive. Some argue that there could even be benefits in having these plants in such areas because of the shade, which the collectors provide, and the jobs, which their installation and maintenance create. 

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