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 15-2Figure 15-2

Fig. 15-2, p. 336

Volcanoes

Folded mountain belt

Abyssal floor

Oceanic ridge

Abyssal floor TrenchAbyssal hills

Craton

Abyssal plain

Oceanic crust (lithosphere)

Continental Continental shelfshelf

Aby

ssal

pla

in

Continental slope

Continental rise

Continental crust (lithosphere) Mantle (lithosphere)

Mantle (lithosphere)

Mantle (asthenosphere)

Fig. 15-3, p. 337

Spreading center Ocean

trench

Plate movement

Subduction zone

Oceanic crust

Continental crust

Continental crust

Material cools as it reaches

the outer mantle

Cold dense material falls back through

mantleHot

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

Tect

onic

pl

ate

Oceanic 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 15-4Figure 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 15-4Figure 15-4

Fig. 15-4, p. 338

Fig. 15-4a, p. 338

EURASIAN PLATEEURASIAN PLATENORTH NORTH AMERICAN AMERICAN PLATEPLATE

ANATOLIAN ANATOLIAN PLATEPLATE

JUAN DE JUAN DE FUCA PLATEFUCA PLATE

CHINA CHINA SUBPLATESUBPLATE

CARIBBEAN CARIBBEAN PLATEPLATE

PHILIPPINE PHILIPPINE PLATEPLATE

ARABIAN ARABIAN PLATEPLATEAFRICAN AFRICAN

PLATEPLATEPACIFIC PACIFIC PLATEPLATE SOUTH SOUTH

AMERICAN AMERICAN PLATEPLATENAZCA NAZCA

PLATEPLATEINDIA-INDIA-

AUSTRALIAN AUSTRALIAN PLATEPLATE

SOMALIAN SOMALIAN SUBPLATESUBPLATE

ANTARCTIC PLATEANTARCTIC PLATE

Divergent plate boundaries

Convergent plate boundaries

Transform faults

Fig. 15-4b, p. 338

Trench Volcanic island arc Craton

Transform fault

LithosphereSubduction zone

Lithosphere Lithosphere

Asthenosphere Asthenosphere Asthenosphere

Divergent plate boundaries Convergent plate boundaries Transform 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 15-5Figure 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 15-8Figure 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 magmaEx. 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 heatEx. 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 15-9Figure 15-9

Fig. 15-10, p. 344

Natural Capital Degradation

Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources

StepsSteps Environmental effectsEnvironmental 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