Energy

GEOLOGIC PROCESSES The earth is made up of a core, mantle, and crust and is constantly changing as a result of processes taking place on and below its surface. The earth’s interior consists of: Core: innermost zone with solid inner core and molten outer core that is extremely hot. Mantle: solid rock with a rigid outer part (asthenosphere) that is melted pliable rock. Crust: Outermost zone which underlies the continents.

GEOLOGIC PROCESSES Major features of the earth’s crust and upper mantle. Figure 15-2

Fig. 15-2, p. 336 Volcanoes Folded mountain belt Abyssal floor Oceanic ridge Abyssal floor Trench Abyssal hills Craton Abyssal plain Oceanic crust (lithosphere) Continental shelf Abyssal plain Continental slope Continental rise Continental crust (lithosphere) Mantle (lithosphere) Mantle (asthenosphere)

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

GEOLOGIC PROCESSES Huge volumes of heated and molten rock moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface. Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on magma or molten rock.

The Earth’s Major Tectonic Plates Figure 15-4

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 transform plate boundaries. Figure 15-4

Fig. 15-4, p. 338

Fig. 15-4a, p. 338 EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE JUAN DE FUCA PLATE CHINA SUBPLATE CARIBBEAN PLATE PHILIPPINE PLATE ARABIAN PLATE AFRICAN PLATE PACIFIC PLATE SOUTH AMERICAN PLATE NAZCA PLATE INDIA- AUSTRALIAN PLATE SOMALIAN SUBPLATE ANTARCTIC PLATE Divergent plate boundaries Convergent plate boundaries Transform faults

Fig. 15-4b, p. 338 TrenchVolcanic island arcCraton Transform fault Lithosphere Subduction zone Lithosphere Asthenosphere Divergent plate boundariesConvergent plate boundariesTransform faults Rising magma

Pacific Plate The Pacific plate is off the coast of California. Lots of volcanoes and earthquakes occur here. “California will fall into the ocean” idea. It is the largest plate and the location of the ring of fire.

Boundaries Divergent – the plates move apart in opposite directions.

Convergent – the plates push together by internal forces. At most convergent plate boundaries, the oceanic lithosphere is carried downward under the island or continent. Earthquakes are common here. It also forms an ocean ridge or a mountain range.

Boundaries (Continued) Transform – plates slide next or past each other in opposite directions along a fracture. California will not fall into the ocean!

GEOLOGIC PROCESSES The San Andreas Fault is an example of a transform fault. Figure 15-5

Importance Plate movement adds new land at boundaries, produces mountains, trenches, earthquakes and volcanoes.

The Rock Cycle – the interaction of processes that change rocks from one type to another

Rock Cycle Figure 15-8

Fig. 15-8, p. 343 Erosion Transportation Weathering Deposition Igneous rock Granite, pumice, basalt Sedimentary rock Sandstone, limestone Heat, pressure Cooling Heat, pressure, stress Magma (molten rock) Melting Metamorphic rock Slate, marble, gneiss, quartzite

Steps

Oxygen The most abundant element in Earth’s crust.

Nitrogen The most abundant element in the Earth’s atmosphere.

Iron The most abundant element in the Earth’s core.

Aluminum The element commercially extracted from bauxite

Relationships Between All Three Rocks All three rocks are being recycled and converted to all of the classes

Igneous Description – forms the bulk of the earth’s crust. It is the main source of many non-fuel mineral resources. Classification – Intrusive Igneous Rocks – formed from the solidification of magma below ground Extrusive Igneous Rocks – formed from the solidification of lava above ground Rock Classification

Igneous (Continued) Examples – Granite, Pumice, Basalt, Diamond, Tourmaline, Garnet, Ruby, Sapphire

Sedimentary Description – rock formed from sediments. Most form when rocks are weathered and eroded into small pieces, transported, and deposited in a body of surface water.

Clastic – pieces that are cemented together by quartz and calcium carbonate (Calcite). Examples: sandstone (sand stuck together), Conglomerate (rounded & concrete-looking) and Breccia (like conglomerate but w/ angular pieces)

Sedimentary (Continued) Nonclastic – Chemical Precipitates – limestone precipitates out and oozes to the bottom of the ocean (this is why there is a lot of limestone in S.A.) Biochemical Sediments – like peat & coal Petrified wood & opalized wood

Metamorphic Description – when preexisting rock is subjected to high temperatures (which may cause it to partially melt), high pressures, chemically active fluids, or a combination of these Location – deep within the earth

Examples: Contact Metamorphism- rock that is next to a body of magma Ex. limestone under heat becomes marble through crystallization Limestone -> marble sandstone -> quartzite shale -> hornfelds (slate)

Dynamic Metamorphism – earth movement crushes & breaks rocks along a fault. Rocks may be brittle- (rock and mineral grains are broken and crushed) or it may be ductile- (plastic behavior occurs.) Rocks formed along fault zones are called mylonites.

Metamorphic (Continued) Regional Metamorphism – during mountain building; great quantities of rock are subject to intense stresses and heat Ex. cont. shelves ram together

Progressive Metamorphism – One form of rock changing into another shale->slate->schist->gneiss coal->graphite granite->gneiss

Nonrenewable Resources Definition – things human use that have a limited supply; they cannot be regrown or replenished by man

Conservation Definition – using less of a resource or reusing a resource, ex. refilling plastic laundry jugs, reusing plastic bags, etc. Part of the solution Problems – this requires a change in our lifestyle and some people will resist. Dealing with Nonrenewable Resources

Restoration Definition – recycling our resources Examples – aluminum, glass, tin, steel, plastics, etc. Part of the solution Problems – recycling a resource often costs more than using the raw material; we don’t have the technology to recycle everything

Sustainability Definition – prediction of how long specific resources will last; ex. we have a 200 year supply of coal in the U.S. Knowing this helps people make decisions in resource use Problems – these are only predictions; they may not be accurate

ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES The extraction, processing, and use of mineral resources has a large environmental impact. Figure 15-9

Fig , p. 344 Natural Capital Degradation Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources Steps Environmental effects Mining Disturbed land; mining accidents; health hazards, mine waste dumping, oil spills and blowouts; noise; ugliness; heat Exploration, extraction Processing Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Transportation, purification, manufacturing Use Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Transportation or transmission to individual user, eventual use, and discarding

Costs Ownership costs – equipment, labor, safety (insurance), environmental costs (reclamation, pollution control, air monitors, water treatment, etc.), taxes External costs – processing the resource, transporting the resource Marginal costs – research: finding new sources of the resource and new ways to harvest it Harvesting Nonrenewable Resources

Benefits Direct – money received for resources; provides many jobs Indirect – land can be reclaimed (brought back to original condition) and sold for profit.

ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES Minerals are removed through a variety of methods that vary widely in their costs, safety factors, and levels of environmental harm. A variety of methods are used based on mineral depth. Surface mining: shallow deposits are removed. Subsurface mining: deep deposits are removed.

Methods Surface Mining Description – if resource is <200 ft. from the surface, the topsoil is removed (and saved), explosives are used to break up the rocks and to remove the resource, reclamation follows Benefits – cheap, easy, efficient Costs – tears up the land (temporarily), byproducts produce an acid that can accumulate in rivers and lakes

Methods (Continued) Underground Mining Description – digging a shaft down to the resource, using machinery (and people) to tear off and remove the resource Benefits – can get to resources far underground Costs – more expensive, more time-consuming, more dangerous

Methods (Continued) Reclamation Description – returning the rock layer (overburden) and the topsoil to a surface mine, fertilizing and planting it Benefits – restores land to good condition Costs – expensive, time-consuming