Deserts are arid, hot or cold biomes that cover close to one-third of the earth’s surface. From their sunbaked sand dunes, ancient rock shields and barren salt flats to the ice-encrusted continent of Antarctica, all have one thing in common: a lack of water. Deserts receive less than 10 inches of precipitation annually that quickly evaporates in the dry environment. Many deserts are hotbeds of natural resources.
Although a desert is an extreme environment with scarce resources, beneath its surface are huge reserves of naturally occurring resources such as fossil fuels, ore and other valuable minerals that make the world go round.
Deserts and Minerals
Rich mineral resources are found chiefly in deserts, and some are unique to deserts. Those minerals that occur naturally in dry saline inland bodies of water require sediments and near-surface brines for their formation. Minerals such as borax, sodium nitrate, sodium carbonate, bromine, iodine, calcium and strontium compounds are created when water in desert lakes (playa) evaporate.
The dry sands of a basin that was once a huge lake in Africa’s Sahara Desert produce a mineral-rich dust that blows across the Atlantic to the Amazon. It is believed by scientists that this dust enriches the soil that helps sustain the Amazon rainforest.
The Borax Story
Borax is renowned as a detergent booster, cleaner and freshener in its natural, unprocessed state. The boric acid derived from borax is a herbicide and insecticide. It is also used in the manufacture of agricultural chemicals, fire retardants, water softeners, pharmaceuticals, cosmetics, glass, ceramics, enamel, paint and coated paper.
Borax is mined mostly in Searles Lake, Borax Lake and Death Valley in California, salt marshes in Nevada and the Alkali Flat in New Mexico. The industrial phase of Death Valley in the northern Mojave Desert began with the discovery of borax near the mouth of Furnace Creek in 1881. From 1883 to 1889, millions of pounds of borax were extracted from the mines at Harmony Borax Works in Furnace Creek. Massive wagons with seven-foot high wheels were laden with tons of borax and hauled by colossal teams of mules and horses to the railhead near Mojave. The 165-mile journey took 10 days each way over the primitive terrain. This slice of the Old West was the inspiration for the brand “20-Mule Team Borax,” sponsor of the long-running western television series, Death Valley Days. Billions of dollars of the mineral salt have been mined in the Death Valley Desert since those early days.
Economically Important Sodium Nitrate
Sodium nitrate is a saline mineral, or type of salt, that occurs naturally in fruits, vegetables and grains. It is also mined extensively in desert areas, formed through water evaporation. Other minerals such as gypsum, sodium nitrate and sodium chloride (table salt) may also be formed. The Atacama Desert in Chile, South America has the richest cache of sodium nitrate, minerals have been mined since the 1900s, nearly 3 million metric tons alone during World War I.
Sodium nitrate was one of the earliest food preservatives. Before refrigeration, it was used for curing meat and fish. A key ingredient in processed meats such as bacon, sausage, ham and deli meats, it preserves the red color and prevents bacteria. Sodium nitrate is also used in the manufacture of fertilizers, pharmaceuticals, dyes, enamels, explosives and flares.
Oil and natural gas are a complex blend of hydrocarbons formed over millions of years from the decomposition of plants and animals. They occur in liquid (crude oil), gaseous (natural gas), and viscous or solid form known as bitumen (asphalt). Found in tar sands, asphalt is used for roofing and road surfacing throughout the world. Oil and natural gas are the most important of the three primary fossil fuels. Along with coal, they are the world’s primary energy source.
The five largest oil fields in the world are in Saudi Arabia, Kuwait and Iraq. In 1936, oil was discovered in the sub-tropical Arabian Desert, the largest petroleum-producing region in the world ranging over most of the Arabian Peninsula. It is the next largest hot desert after the Sahara where oil was discovered after World War II.
Of the 15 major kinds of mineral deposits formed by groundwater in the Western Hemisphere, 13 occur in deserts. Mineral deposits are created, enhanced or preserved by geologic processes in arid regions due to climate. Groundwater leaches ore minerals and deposits them in areas near the water table, concentrating the minerals so ore can be mined.
Among the many valuable metallic minerals found in deserts are deposits of gold, silver, iron, lead-zinc ore and uranium in the southwestern deserts of the United States and Australia. Copper occurs in the United States, Chile, Peru and Iran.
Southwest Rocks and Gemstones
Deserts of the Southwest are a treasure trove of economically important semi-precious gemstones such as turquoise, opal, quartz, topaz, amethyst, jade, chalcedony, petrified wood, and precious gemstones such as diamonds. Gemstones are used in jewelry and decorative items as well as in flooring, countertops and other building applications.
While many gemstones are also found throughout the world in temperate and other zones, turquoise is found exclusively in desert regions. The most popular and valuable opaque gemstone, turquoise is a mixture of hydrated copper and aluminum phosphate that produces a lustrous stone with an exquisite sky blue or blue-green color and delicate veins known as matrix.