Chapter 15Chapter 15

Geology and Geology and Nonrenewable Mineral Nonrenewable Mineral

ResourcesResources

Chapter Overview QuestionsChapter Overview Questions• What major geologic processes occur within the

earth and on its surface?• What are nonrenewable mineral resources and

where are they found?• What are rocks, and how are they recycled by the

rock cycle?• How do we find and extract mineral resources from

the earth’s crust, and what harmful environmental effects result from removing and using these minerals?

Chapter Overview Questions Chapter Overview Questions (cont’d)(cont’d)

• Will there be enough nonrenewable mineral resources for future generations?

• Can we find substitutes for scarce nonrenewable mineral resources?

• How can we shift to more sustainable use of nonrenewable mineral resources?

Core Case Study: The Core Case Study: The Nanotechnology RevolutionNanotechnology Revolution

• Nanotechnology uses science and engineering to create materials out of atoms and molecules at the scale of less than 100 nanometers.– Little environmental harm:

• Does not use renewable resources.– Potential biological concerns.

• Can move through cell membranes:

Figure 15-1Figure 15-1

GEOLOGIC PROCESSESGEOLOGIC 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 PROCESSESGEOLOGIC PROCESSES

• Major features of the earth’s crust and upper mantle.

Figure 15-2Figure 15-2

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 PROCESSESGEOLOGIC 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 PlatesThe Earth’s Major Tectonic Plates

Figure 15-4Figure 15-4

Animation: Geological ForcesAnimation: Geological Forces

PLAYANIMATION

The Earth’s Major Tectonic PlatesThe 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

Animation: Plate MarginsAnimation: Plate Margins

PLAYANIMATION

GEOLOGIC PROCESSESGEOLOGIC PROCESSES

• The San Andreas Fault is an example of a transform fault.

Figure 15-5Figure 15-5

Wearing Down and Building Up the Wearing Down and Building Up the Earth’s SurfaceEarth’s Surface

• Weathering is an external process that wears the earth’s surface down.

Figure 15-6Figure 15-6

MINERALS, ROCKS, AND THE ROCK MINERALS, ROCKS, AND THE ROCK CYCLECYCLE

• The earth’s crust consists of solid inorganic elements and compounds called minerals that can sometimes be used as resources.– Mineral resource: is a concentration of naturally

occurring material in or on the earth’s crust that can be extracted and processed into useful materials at an affordable cost.

General Classification of General Classification of Nonrenewable Mineral ResourcesNonrenewable Mineral Resources

• The U.S. Geological Survey classifies mineral resources into four major categories:– Identified: known location, quantity, and quality or

existence known based on direct evidence and measurements.

– Undiscovered: potential supplies that are assumed to exist.

– Reserves: identified resources that can be extracted profitably.

– Other: undiscovered or identified resources not classified as reserves

General Classification of General Classification of Nonrenewable Mineral ResourcesNonrenewable Mineral Resources

• Examples are fossil fuels (coal, oil), metallic minerals (copper, iron), and nonmetallic minerals (sand, gravel).

Figure 15-7Figure 15-7

GEOLOGIC PROCESSESGEOLOGIC PROCESSES

• Deposits of nonrenewable mineral resources in the earth’s crust vary in their abundance and distribution.

• A very slow chemical cycle recycles three types of rock found in the earth’s crust:– Sedimentary rock (sandstone, limestone).– Metamorphic rock (slate, marble, quartzite).– Igneous rock (granite, pumice, basalt).

Rock CycleRock Cycle

Figure 15-8Figure 15-8

ENVIRONMENTAL EFFECTS OF USING ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCESMINERAL 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

ENVIRONMENTAL EFFECTS OF USING ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCESMINERAL 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.

Open-pit MiningOpen-pit Mining

• Machines dig holes and remove ores, sand, gravel, and stone.

• Toxic groundwater can accumulate at the bottom.

Figure 15-11Figure 15-11

Area Strip MiningArea Strip Mining

• Earth movers strips away overburden, and giant shovels removes mineral deposit.

• Often leaves highly erodible hills of rubble called spoil banks.

Figure 15-12Figure 15-12

Contour Strip MiningContour 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 15-13Figure 15-13

Mountaintop RemovalMountaintop 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 15-14Figure 15-14

Mining ImpactsMining Impacts

• Metal ores are smelted or treated with (potentially toxic) chemicals to extract the desired metal.

Figure 15-15Figure 15-15

SUPPLIES OF MINERAL RESOURCESSUPPLIES OF MINERAL RESOURCES

• The future supply of a resource depends on its affordable supply and how rapidly that supply is used.

• A rising price for a scarce mineral resource can increase supplies and encourage more efficient use.

SUPPLIES OF MINERAL RESOURCESSUPPLIES OF MINERAL RESOURCES

• Depletion curves for a renewable resource using three sets of assumptions. – Dashed vertical

lines represent times when 80% depletion occurs.

Figure 15-16Figure 15-16

SUPPLIES OF MINERAL RESOURCESSUPPLIES OF MINERAL RESOURCES

• New technologies can increase the mining of low-grade ores at affordable prices, but harmful environmental effects can limit this approach.

• Most minerals in seawater and on the deep ocean floor cost too much to extract, and there are squabbles over who owns them.

Getting More Minerals from the Getting More Minerals from the OceanOcean

• Hydrothermal deposits form when mineral-rich superheated water shoots out of vents in solidified magma on the ocean floor.

Figure 15-17Figure 15-17

USING MINERAL RESOURCES MORE USING MINERAL RESOURCES MORE SUSTAINABLYSUSTAINABLY

• Scientists and engineers are developing new types of materials as substitutes for many metals.

• Recycling valuable and scarce metals saves money and has a lower environmental impact then mining and extracting them from their ores.

Fig. 15-18, p. 351

Solutions

Sustainable Use of Nonrenewable Minerals

• Do not waste mineral resources.

• Recycle and reuse 60–80% of mineral resources.

• Include the harmful environmental costs of mining and processing minerals in the prices of items (full-cost pricing).

• Reduce subsidies for mining mineral resources.

• Increase subsidies for recycling, reuse, and finding less environmentally harmful substitutes.

• Redesign manufacturing processes to use less mineral resources and to produce less pollution and waste.

• Have the mineral-based wastes of one manufacturing process become the raw materials for other processes.

• Sell services instead of things.

• Slow population growth.

Case Study: Case Study: The Ecoindustrial RevolutionThe Ecoindustrial Revolution

• Growing signs point to an ecoindustrial revolution taking place over the next 50 years.

• The goal is to redesign industrial manufacturing processes to mimic how nature deals with wastes.– Industries can interact in complex resource

exchange webs in which wastes from manufacturer become raw materials for another.

Case Study: Case Study: The Ecoindustrial RevolutionThe Ecoindustrial Revolution

Figure 15-19Figure 15-19