Chapter 15 Geology and Nonrenewable Mineral Resources

Pangaea 18 simulation

The Earth’s Major Tectonic Plates Figure 15-4

Geologic Processes  Structure of the Earth 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.) Crust Lithosphere Asthenosphere (depth unknown) Age of the earth??

Fig. 15-3, p. 337 Spreading center Ocean trench Plate movement Subduction zone Oceanic crust Continental crust Material cools as it reaches the outer mantle Cold dense material falls back through mantle Hot material rising through the mantle Mantle convection cell Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Mantle Hot outer core Inner core Plate movement Collision between two continents Tectonic plate Oceanic tectonic plate Oceanic crust

The Earth’s Major Tectonic Plates The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart at divergent plate boundaries and slide past at LATERAL plate boundaries. Figure 15-4

Lateral movement

Natural Hazards: Earthquakes  Features  Magnitude Liquefaction of recent sediments causes buildings of sink Landslides may occur on hilly ground Shockwaves Epicenter Focus Two adjoining plates move laterally along the fault line Earth movements Cause flooding in Low-lying areas

What is a mineral? Elements come together to form minerals General characteristics of minerals –1.Natural ( not man made) –2.Inorganic –3.Crystalline –4.Solid –5.Constant chemical composition.

Minerals and Rocks Rock Types  Igneous  Sedimentary  Metamorphic

Rock Cycle Figure 15-8

External Earth Processes  Erosion-worn away and deposited  Mechanical weathering  Frost and salt wedging  Chemical weathering

Soils: Formation  Soil horizons  Soil profile  Humus O horizon Leaf litter A horizon Topsoil B horizon Subsoil C horizon Parentmaterial Mature soil Young soil RegolithRegolith BedrockBedrock Immature soil

Open-pit Mining Machines dig holes and remove ores, sand, gravel, and stone. Toxic groundwater can accumulate at the bottom. Figure 15-11

Contour Strip Mining Used on hilly or mountainous terrain. Unless the land is restored, a wall of dirt is left in front of a highly erodible bank called a highwall. Figure 15-13

Mountaintop Removal Machinery removes the tops of mountains to expose coal. The resulting waste rock and dirt are dumped into the streams and valleys below. Figure 15-14

Surface Mining Control and Reclamation Act  Established 1977  Mine lands must be restored to pre- mining conditions  Taxes on mining companies to restore pre-1977 sites  Limited success-Lobbying of officials have choked off funds for enforcement

Environmental Effects of Mining Mineral Resources  Disruption of land surface  Subsidence  Acid mine drainage  Air pollution  Storage and leakage of liquid mining waste-acids, cyanide, mercury

Fig , p. 352 Sludge Pharmaceutical plant Local farmers Sludge Greenhouses Waste heat Fish farming Oil refinery Surplus natural gas Electric power plant Fly ash Surplus sulfur Surplus natural gas Waste calcium sulfate Waste heat Cement manufacturer Sulfuric acid producer Wallboard factory Area homes

Rock lab guidelines Go by the numbers on the white pieces of paper in the tray. VERY IMPORTANT Know the category-Igneous, metamorphic, sedimentary Grades based on how many names correctly identified. Each number unique name. No two the same. No talking between groups. One free check PER GROUP

Rock lab Omit –Igneous: gabbro, andesite –Metamorphic: schist, quartizite –Sedimentary: siltstone, shale,rocksalt,rock gypsum, tufa, organic limestone.

Will Durant Civilization exists by geological consent, subject to change without notice. End of chapter 15