Chapter 14

Mantle

Core

Crust

Low-velocity zone

Solid

Outer core(liquid)

Innercore(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

CHINASUBPLATE PHILIPINE

PLATE

INDIAN-AUSTRLIAN PLATE

PACIFICPLATE

JUAN DEFUCA PLATE

COCOSPLATE

CARIBBEAN PLATE

NORTHAMERICAN

PLATE

SOUTHAMERICAN

PLATE

EURASIAN PLATE

ANATOLIAN PLATE

ARABIAN PLATE

AFRICAN PLATE

AFRICAN PLATE

CarlsbergRidge

Southwest IndianOcean Ridge

ANTARCTIC PLATE

Transformfault

East PacificRise

Transformfault

Mid-IndianOceanRidge

Southeast IndianOcean Ridge

Mid-AtlanticOceanRidge

ReykjanesRidge

Transformfault

Divergent ( ) andtransform fault ( )boundaries

Convergentplate boundaries

Plate motionat convergentplate boundaries

Plate motionat divergentplate boundaries

Explains and unifies many geologic theories

1960’sBasically 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

Trench Volcanic island arc

Asthenosphere

Risingmagma

Subductionzone

Trench and volcanic island arc at a _____________________________________________________

Fracture zone

Transformfault

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 erodedMechanical (frost weathering)Chemical Biological

1. 2. 3. 4.

Combination of mineralsMay be organicCan contain fossils

Forms when _______________________ cools and hardens Intrusive form INSIDE the crustExtrusive 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

Earthquakes

Liquefaction ofrecent sedimentscauses buildingsof sink

Landslides mayoccur onhilly ground

Shockwaves

Epicenter

Focus

Two adjoining platesmove laterally alongthe fault line Earth movements

Cause flooding inLow-lying areas

Caused by movement of tectonic plates

P-waves and S-waves

see earthquake activity

Volcanoes

extinctvolcanoes

magmareservoir

centralvent

magmaconduit

Solidlithosphere

Upwellingmagma Partially molten

asthenosphere

1.

2.

3.

3 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 acreThen 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 landLease it for up to 20 yearsPay royalties on whatever they

removeStricter 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 imagesDetect 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 profitablyMineral + 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-pitDredging of underwater mineral depositsArea strip miningContour strip mining

Subsurface miningdisturbs less than 1/10 as much land as surface

miningmore 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:

ArsenicBariteCalciteCyanideFluoriteMercuryPyriteQuartz

Disruption of landSubsidence of landWind or water erosion of mineral wasteAcid mine drainage sulfuric acid

releasedEmission of toxic chemicals into the airLeakage of toxic wastes into waterwaysSmelting separates the metals from

other substances made into products which are used and then recycled or discardedthis process emits huge quantities of air

pollutants (without effective pollution controls)water pollutionproduces hazardous wastes

Reclamation – make land suitable for another purpose (agriculture, recreation, etc)

Restoration – restore native habitatRegrading the land to original topographyReplacing topsoilPlanting native vegetation

Steps Environmental Effects

exploration, extraction

MiningDisturbed 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 healthhazards; ugliness; heat

Processing

transportation, purification,manufacturing

Use

transportation or transmissionto individual user,

eventual use, and discarding

Noise; uglinessthermal water pollution;

pollution of air, water, and soil;solid and radioactive wastes;

safety and health hazards; heat

Percolation to groundwater

Leaching of toxic metalsand other compounds

from mine spoil

Acid drainage fromreaction of mineralor ore with water

Spoil banks

Runoff ofsediment

Surface MineSubsurfaceMine Opening

Leaching may carryacids into soil andgroundwater

supplies

Surface mining

Metal ore

Separationof ore fromgangue

Scattered in environment

Recycling

Discarding of product

Conversion to product

Melting metal

Smelting

Fig. 14.8, p. 327

Economic depletionMining 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 72% of US Public lands are in Alaska; 22% are

in western statesUsing alternative products ceramics,

plastics

Present Depletiontime A

Depletiontime B

Depletiontime C

Time

Pro

du

ctio

n

C

B

A

Recycle, reuse, reduceconsumption; increasereserves by improvedmining technology,higher prices, andnew discoveries

Recycle; increase reservesby improved miningtechnology, higher prices,and new discoveries

Mine, use, throw away;no new discoveries;rising prices