Chapter 14

Mantle Core Crust Low-velocity zone Solid Outer core (liquid) Inner core (solid) 35 km (21 mi.) avg., 1,200˚C 2,900km (1,800 mi.) 3,700˚C 5,200 km (3,100 mi.), 4,300˚C 10 to 65km 100 km 200 km 100 km (60 mi.) 200 km (120 mi.) ________________ ___________________ _________________ (depth unknown)

EURASIAN PLATE CHINA SUBPLATE PHILIPINE PLATE INDIAN-AUSTRLIAN PLATE PACIFIC PLATE JUAN DE FUCA PLATE COCOS PLATE CARIBBEAN PLATE NORTH AMERICAN PLATE SOUTH AMERICAN PLATE EURASIAN PLATE ANATOLIAN PLATE ARABIAN PLATE AFRICAN PLATE AFRICAN PLATE Carlsberg Ridge Southwest Indian Ocean Ridge ANTARCTIC PLATE Transform fault East Pacific Rise Transform fault Mid- Indian Ocean Ridge Southeast Indian Ocean Ridge Mid- Atlantic Ocean Ridge Reykjanes Ridge Transform fault Divergent ( ) and transform fault ( ) boundaries Convergent plate boundaries Plate motion at convergent plate boundaries Plate motion at divergent plate boundaries

Explains and unifies many geologic theories 1960’s Basically describes how the Earth’s crust is made of plates that move around on top of the upper liquid portion of the mantle

_______________________________ helps to explain how populations become separate species as the continents move apart

Lithosphere Asthenosphere Oceanic ridge at a _______________________

Lithosphere TrenchVolcanic island arc Asthenosphere Rising magma Subduction zone Trench and volcanic island arc at a _____________________________________________________

Fracture zone Transform fault Lithosphere Asthenosphere ________________________________________________ connecting two divergent plate boundaries

Materials are dissolved, loosened, or worn away from one part of the Earth’s surface to another

Process that breaks down rocks into smaller pieces that can be eroded Mechanical (frost weathering) Chemical Biological

Combination of minerals May be organic Can contain fossils

Forms when _______________________ cools and hardens Intrusive form INSIDE the crust Extrusive form on/ outside the crust Ex: granite, lava rock

Formed from ______________________ that become compacted Ex: coquina, sandstone, shale

Rock is subjected to high ________________ ______________________________________ Ex: anthracite, marble, slate

Volcanoes Earthquakes

Liquefaction of recent sediments causes buildings of sink Landslides may occur on hilly ground Shock waves Epicenter Focus Two adjoining plates move laterally along the fault line Earth movements Cause flooding in Low-lying areas

Caused by movement of tectonic plates P-waves and S-waves see earthquake activity

Volcanoes extinct volcanoes magma reservoir central vent magma conduit Solid lithosphere Upwelling magma Partially molten asthenosphere

Types of Volcanoes

To encourage mineral exploration and mining out West Anyone can buy public land (except parks or wilderness) by patenting it

Must say they think there are minerals there and that they will spend at least $500 to improve the land for mineral development Pay $2.50- $5.00 an acre Then they can do whatever they want with it

Mining companies (F & D) remove $2-3 BILLION in resources each year from land they got this way! About 20% of companies with mining rights on US public lands are FOREIGN!

Modified in 1992 to require companies to post bonds to cover the full amount of a clean up in case the company goes bankrupt Clean up would cost taxpayers $33-72 Billion Lobbyists are trying to weaken these laws

Don’t sell the land Lease it for up to 20 years Pay royalties on whatever they remove Stricter clean up requirements

Concentration of naturally occurring material in or on the crust that can be extracted & processed at a reasonable cost Take a long time to produce ______________________________________ Energy

________________________________: we know where they are and how much there is _________________________: resources we can extract at a reasonable price ________________________________: potential supplies, don’t know for sure it is there or how much there is Other- discovered or undiscovered but not a reserve

Aerial photos and satellite images Detect radiation from radioactive deposits (Uranium) Magnetometer to detect changes in magnetic field (Iron ore) Gravimeter to detect changes in gravity caused by different densities of rock

_______________:a rock containing enough metallic minerals to be mined profitably Mineral + unwanted gangue ________________:gangue that has been separated from the desired mineral ________________:identified resources from which nonrenewable minerals can be extracted profitably

The most common way that ore deposits form is through hydrothermal processes: especially at divergent boundaries  superheated seawater dissolves metals hydrothermal vents support marine ecosystems based on chemosynthesis sedimentary sorting based on density (panning for gold) evaporite mineral deposits  water evaporates leaving minerals residual deposits  left when soluble minerals are washed away thereby concentrating insoluble minerals nonrenewable

Overburden of soil and rock is removed and discarded as spoil Types of Surface Mining: Open-pit Dredging of underwater mineral deposits Area strip mining Contour strip mining Subsurface mining disturbs less than 1/10 as much land as surface mining more hazardous, more expensive, less productive

Open Pit Mine

Dredging

Area Strip Mining

Contour Strip Mining

Subsurface: Underground Coal Mine

_______________________ are the waste materials left over after removing the minerals from ore. Tailings are sometimes reprocessed. Common contents of tailings: Arsenic Barite Calcite Cyanide Fluorite Mercury Pyrite Quartz

Disruption of land Subsidence of land Wind or water erosion of mineral waste Acid mine drainage  sulfuric acid released Emission of toxic chemicals into the air Leakage of toxic wastes into waterways Smelting  separates the metals from other substances  made into products which are used and then recycled or discarded this process emits huge quantities of air pollutants (without effective pollution controls) water pollution produces hazardous wastes

Reclamation – make land suitable for another purpose (agriculture, recreation, etc) Restoration – restore native habitat Regrading the land to original topography Replacing topsoil Planting native vegetation

StepsEnvironmental Effects exploration, extraction Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing transportation, purification, manufacturing Use transportation or transmission to individual user, eventual use, and discarding Noise; ugliness thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat

Percolation to groundwater Leaching of toxic metals and other compounds from mine spoil Acid drainage from reaction of mineral or ore with water Spoil banks Runoff of sediment Surface Mine Subsurface Mine Opening Leaching may carry acids into soil and ground water supplies

Surface mining Metal ore Separation of ore from gangue Scattered in environment Recycling Discarding of product Conversion to product Melting metal Smelting Fig. 14.8, p. 327

Economic depletion Mining lower grade ores, mining ocean floor. seawater extraction  expensive! Mining is subsidized in US  government tax deductions, depletion allowances, Mining Law of 1872 Sagebrush Rebellion in the 80’s  miners, ranchers, etc. pushed for opening up federal public lands for use Sagebrush Rebellion 72% of US Public lands are in Alaska; 22% are in western states Using alternative products  ceramics, plastics

PresentDepletion time A Depletion time B Depletion time C Time Production C B A Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries Recycle; increase reserves by improved mining technology, higher prices, and new discoveries Mine, use, throw away; no new discoveries; rising prices