Metamorphic ore deposits regional metamorphism also

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Unformatted text preview: Chalcopyrite Disseminated Deposits _______________________Ores precipitated as minute masses throughout entire rock mass; Surface Deposits ________________Where magma is near surface, dissolved metals precipitate when water cools in air. Metamorphic Ore Deposits Regional metamorphism ________________________also generates useful metamorphic ore deposits. Examples: Talc Graphite Secondary Enrichment Weathering Dissolves •  ____________________ scattered bits of ore; •  Groundwater carries dissolved metals to subsurface; •  Concentrated ore deposit forms where metals precipiate in cracks _____________________ •  Examples: copper, silver. Copper Silver zinc zinc lead lead copper copper Weathering and Ore Deposits Secondary enrichment _____________________Concentration of scattered, minor amounts of metals by weathering processes. Two Types: 1. Chemical weathering and water percolation remove undesireable elements from decomposing rock, leaving desireable elements; 2. Desirable elements found near surface are carried to lower zones, and concentrated. Secondary Enrichment Bauxite ____________: Principal ore of _________, formed by secondary aluminium enrichment in rainy tropical climates; silicate rocks are chemically weathered and other elements leached out, leaving a concentration of bauxite. 3 5/1/12 Positive: very concentrated Negaive: have to strip mine it can find diamonds among bits of clay Placer Deposits Placers ________deposits formed when heavy minerals are mechanically concentrated ___________________________ by currents, most commonly streams and waves; typically heavy and durable minerals. Examples: Gold, tin, platinum, diamonds. Nonmetallic Mineral Resources Building Materials ____________________________ •  Natural aggregates (crushed stone, sand, gravel); •  Gypsum (plaster and wallboard); •  Clay (tile, bricks, and cement). Nonmetallic Mineral Resources Industrial Minerals: _Fertilizers (nitrate, phosphate, _________ and potassium compounds); Sulfur ___________(sulfuric acid to manufacture phosphate fertilizers); salt ____(used in chemical industry, “softening” residential water, and keeping streets ice-free). Salt Works Earth s Systems Sea salt •  ________is key resource in some coastal areas: •  Water evaporated from sea brine in shallow, salt evaporation ponds ________________________ •  Most economical when powered by solar energy; •  Primarily industry of warm, dry climates. Salt ponds in Ile de Ré, France San Francisco Bay salt ponds 4...
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