1. Geology & Minerals
Chapter 16

2. Geology
The study of dynamic processes occurring on Earth’s surface & in its interior
Core- innermost; intensely hot; inner solid surrounded by semisolid (molten)
Mantle- surrounds core; most is solid rock
Crust- outermost; thinnest layer

3. Movements in the Mantle
Convection currents- movement of large amounts of rock (due to heat) in loops through the mantle like conveyor belt
Mantle plume- mantle rock flows upward (like smoke from chimney)

4. Plate Tectonics Tectonic plate- huge rigid plate made of lithosphere
Lithosphere- crust & uppermost mantle
Asthenosphere- molten area of mantle beneath lithosphere
Theory of Plate Tectonics- explains movement of plates & processes that occur where plates meet
Importance- explains volcanoes, earthquakes, climates, mineral deposits, & patterns of evolution

5. Plate Boundaries
Divergent boundary- plates move apart; results in rift valley surrounded by mountain range (typically in middle of ocean basin); new crust is created
Transform Fault boundary- plates slide past each other without creating or destroying crust

6. Convergent boundary- plates move toward each other; subduction occurs; older crust is recycled into mantle
Oceanic – Oceanic- trench (older crust is subducted); volcanic island arc
Oceanic – Continental- trench (oceanic is subducted); continental volcanic arc (folded mountains)
Continental – Continental- mountain range (isostatic balance – crust is too buoyant to be subducted)

7. Erosion & Weathering
Erosion- process of dissolving, loosening, or wearing away of crust; material is deposited at new location
Weathering- physical, chemical, biological processes that break down rocks & minerals

8. Types of Weathering Mechanical- breaks rock into smaller pieces
Frost wedging- freeze/thaw cycle of water in the cracks of rocks
Chemical- chemical reactions change rocks into simpler substances
Water is most common agent
Biological- rocks/minerals changed into smaller pieces by living things
Lichen

9. Earthquakes Movement along a fault
Shaking, damage to people, buildings, bridges, overpasses, dams, pipelines
Rockslides, fire, flooding, tsunamis

10. Reducing the Hazards Locate active fault lines
Map high-risk areas & establish building codes for building placement & design
Increase research on prediction
More earthquake resistant structures

11. Volcanoes Eruption- release of ejecta, lava, & gas into environment
Cooler climate due to ash in atmosphere, covering of roads & villages, fire
Scenery (Crater Lake, mountains), highly fertile soil (weathering of lava)

12. Reducing the Hazards Identify high-risk areas Develop evacuation plans
Develop warning system

13. Rocks & Minerals
Mineral- solid, inorganic substance with definite chemical composition & crystalline structure
Rock- mineral or mineral-like matter that is naturally occurring
Igneous- cooling & hardening of magma or lava
Sedimentary- compaction & cementation of sediments
Metamorphic- high temperatures/pressures or chemical reactions are applied to existing rock

14. Rocks All minerals are rocks. All rocks are NOT minerals.
Igneous- granite, pumice, obsidian
Sedimentary- sandstone, limestone, rock salt
Metamorphic- slate, marble

15. Rock Cycle DRAW YOUR OWN. Be sure to include: Compaction/cementation
weathering/erosion
Heat/pressure/chemical rxn
Cooling/hardening
Melting
Sediments
Magma/lava
All 3 types of rocks

16. Mineral Resources
Nonrenewable materials that can be extracted from Earth’s crust
Ore- can be mined for profit
Identified resource- known location, quantity, quality
Undiscovered- assumed to exist; unknown specific location, quantity, quality
Reserves- identified areas where ore exists
Other resources- undiscovered, identified but not as reserve

17. Locating Deposits Aerial photographs Satellite images
Radiation measuring equipment
Magnetometer- changes in magnetic field
Gravimeter-density differences
Seismic surveys- composition of buried layers
Chemical analysis- leaching

18. Removing Deposits Subsurface mining- removes deeper deposits
Surface mining- removes shallow deposits
Open-pit mining- machine digs large hole
Dredging- chain buckets & draglines scrape underwater
Area-strip mining- used in flat areas, overburden is removed, power shovel removes mineral

19. Contour strip mining- (mountainous terrain) terraces cut, overburden removed, power shovel removes mineral
Mountaintop removal- explosives, massive shovels, machinery remove top of mountain to expose mineral

20. Environmental Effects of Mining
Scarring & disruption of land surface
Subsidence
Erosion of soil
Large amounts of toxic solid waste
Acid mine drainage

21. Economic Depletion
Costs more to find, extract, transport, process remaining deposit than it is worth
Choices:
Recycle or reuse existing supplies
Waste less
Use less
Find a substitute
Do without

22. Free Market Plentiful resource = cheaper price
Scarce resource = higher price
Encourages exploration for new deposits
Development of better mining technology
Profitable to mine lower-grade ores
Search for substitute
Promote resource conservation

23. Why it does NOT work…
Industry & government control supply & demand & prices
Economic problems hinder new supplies of mineral resources

24. Mining on Public Lands