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Earth’s Buried Treasures The Economic Importance of Minerals and Mineral Resources The Economic Use of Minerals Minerals in Society Economically ImportantIndustrial Mineral Important Non-metal Minerals Deposits Sand and gravel Clay minerals Crushed rock Salt Silica sand Phosphate 18.13.c-d Economically Important Minerals Economically Important Minerals Economically Important Minerals The Economic Use of Mineral Tidbit: Minerals Did you ever wonder why “quartz” is used in watches? • When a small electrical current is applied to quartz it vibrates at a very precise rate of 100,000 vibrations per second Locating Mineral How do Geologists Locate Mineral Deposits? Resources 18.12.a-b 3) Analyze the chemistry of rocks 1) Look for rocks altered by fluids 4) Reconstruct the geologic history of area 2) Chemically altered rocks (events make, hide, or destroy deposit) Locating Mineral How do Geologists Locate Mineral Deposits? Resources Use geologic maps to identify favorable rocks and structures Above: Traditional geologic map Left: 3-D geologic map Locating Mineral Locating Buried Mineral Deposits Resources Conduct surveys using geophysical methods, including magnetic surveys Note where the magnetic strength is high over ore body 18.12.c1 Locating Mineral How do Geologists Locate Mineral Deposits? Resources A gravimeter is a specialized type of accelerometer designed for measuring the local gravitational field of the Earth. Commonly, gravimeters are used in petroleum and mineral mining, as well as for various types of geophysical research, Locating Mineral Geologists analyzing a geophysical map of region Resources Locating Mineral How do Geologists Locate Mineral Deposits? Resources Airborne Geophysical Survey Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. Locating Mineral Resources Locating Mineral How do Geologists Locate Mineral Deposits? Resources Ground-penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This nondestructive method uses electromagnetic radiation in the microwave band (UHF/VHF frequ encies) of theradio spectrum, and detects the reflected signals from subsurface structures. GPR can be used in a variety of media, including rock, soil, ice, fresh water, pavements and structures. It can detect objects, changes in material, and voids and cracks. Locating Mineral Resources Locating Mineral Deposits Core sampling is the process of taking a solid core of rock (usually about 50mm in diameter) out of the rock; using a specialized circular drill bit; much like a hole saw used on an electric drill. As the bit cuts through the rock, the round core passes up through the drill, and through the hollow drill rods, attached to the bit. The entire core may be many feet long, broken into handleable sections. Core drilling is the only certain way of determining the composition of the underground rocks; and is an invaluable tool in mineral exploration and mine development. Mining companies often take cores, during both the exploration and development stages of mining. Government geological survey bodies also often take core samples for general knowledge, and store them in 'core libraries'; where they may be inspected by geologists. Locating Mineral Resources Locating Mineral Resources Locating Mineral Resources CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) uses reflectance spectroscopy to identify minerals on the martian surface. Locating Mineral Resources Afghanistan’s Buried Riches • • • • Under military cover, U.S. geologists have mapped Afghanistan’s deposits of critical minerals. Rich reserves of rare-earth elements exist in the south, where Taliban control is tightest. If mining of important minerals can take off in the north, that success could create enormous commercial and political momentum for opening the south. New estimates indicate that rare earths could be triple the initial predictions. Overcoming the country’s opium and Taliban strongholds with a mining bonanza could change U.S. foreign policy and world stability. Over the long term, Afghanistan’s geologists will have to take charge. The U.S. Geological Survey is nearly done training them. Conclusion Earth’s Buried Treasures The Economic Importance of Minerals and Mineral Resources