Ores form in arid climates 17 nonmetallic resources

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Unformatted text preview: reat depth (>150 km) and rises quickly to the surface, picking up diamonds from the upper mantle 18 Kimberlite Pipes & Diamonds Diamonds form at high pressure, deep in the crust, under “old, cold” lithosphere Fossil Fuels derived from the sun’s energy via decayed organic matter organic carbon oxidized to form heat energy 19 Fossil Fuels Coal From the decay of land plants rich in resins, waxes, and lignins Organic matter accumulated in swamps Burial results in peat-lignite-sub-bituminous and bituminous coal Widespread distribution, e.g. Carboniferous N.S. & B.C. Plentiful supply but pollution?? The Process of Forming Coal Peat Lignite Bituminous Coal Anthracite U.S. Coal Fields 20 Indiana Coal Strip Mine: Before Reclamation Indiana Coal Strip Mine: After Reclamation Fossil Fuels Oil & Gas Unlike coal - derived from the remains of marine plants and animals rich in proteins lipids & carbohydrates Formation complex & incompletely known Deposition of sediments rich in plant & animal remains under anoxic conditions Burial over millions of years produces hydrocarbons dt/dp must be i.e. correct petroleum window 21 Oil & Gas Petroleum Window: dt/dp Fossil Fuels Oil & Gas Cont’d. Most petroleum formed in shales from where it migrates upward Reservoirs must be porous & permeable Oil-pools!! Trap (anticline, fault or stratigraphic) that is an impermeable seal is necessary to hold fluid Types of Oil Traps 22 Gulf of Mexico Fossil Fuels Oil Shale Contains kerogen, a waxy substance from which fuels can be derived Found in abundance in western US Deposited in vast shallow lakes 50 m.y. ago Exploitation energy intensive Fossil Fuels Tar Sands Viscous and “immature” oil that cannot be pumped Also found in shales and limestones Alberta has major resources: ~10% can be mined; remainder heated and pumped 23 Estimated worldwide oil reserves by region at the end of 2000 Gas Hydrates A new resource Clathrate structure in which gas (CH4) is enclosed in a water molecule cage Found in cold temperature relatively high pressure at the bottom of ocean basins in hydrated sediment layers. The methane is produced from the breakdown of biological materials Possibly a huge potential source of clean energy Impacts of gas hydrates Evidence suggests that there was a large injection of methane into atmosphere at ca. 55 Ma Evidence in fossil record of forams and their C isotope records show that a massive amount of carbon was released in a short period of time (hundreds of years) Oxygen isotope record shows that surface temperatures may have increased by as much as 7ºC Ocean warming may have triggered release of frozen methane - a green house gas The methane would quickly have oxidized to form CO2 Presence of gas hydrates can affect stability of slopes leading to slope failure and large submarine landslides 24...
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