1. Geology and Nonrenewable Minerals
Chapter 14
PART 1

2. GEOLOGIC TIMESCALE
Geologists have divided Earth's history into a series of time intervals.
The geologic time scale was constructed to visually show the duration of each time unit.
The Earth is 4.6 billion years old.
The geologic processes have been happening for a very long time.
Humans just showed up at the end.

3. GEOLOGIC TIMESCALE
The time intervals are variable in length. This is because geologic time is divided using significant events in the history of the Earth.
New biological developments
Mass extinctions

4. 14-1 What Are the Earth’s Major Geological Processes and Hazards?
Concept 14-1A Gigantic plates in the earth’s crust move very slowly atop the planet’s mantle, and wind and water move the matter from place to place across the earth’s surface.
Concept 14-1B Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage.

5. The Earth Is a Dynamic Planet
The earth’s interior consists of:
Core: innermost zone with solid inner core and molten outer core that is extremely hot
Mantle: liquid rock with a rigid outer part (asthenosphere) that is melted pliable rock
Crust: layer of solid rock (lithosphere) which underlies the continents and the oceans
Continental crust
Oceanic crust

6. The Earth Beneath Your Feet is Moving
Plate Tectonics
The theory that Earth’s crust is divided into huge tectonic plates that float on magma or molten rock.
Convection currents within the mantle move the plates around.
Evidence:
Puzzle-like fit of the continents
Matching plant/animal fossils on opposite sides of oceans
Matching rock layers on opposite sides of oceans
Evidence of past climates

7. The Earth’s Major Tectonic Plates

8. Major Features of the Earth’s Crust and Upper Mantle

9. Tectonic Plate Boundaries
Plates move apart at divergent plate boundaries.
Mid-ocean ridge – the site of sea-floor spreading

10. Tectonic Plate Boundaries
Plates grind into one another at convergent plate boundaries.
Folded mountains
Volcanic mountains

11. Tectonic Plate Boundaries
Plates slide past one another at transform plate boundaries.

12. Some Parts of the Earth’s Surface Build Up and Some Wear Down
Internal geologic processes
Generally build up the earth’s surface
Result from the heat generated by the Earth’s interior
External geologic processes
Wear down the Earth’s surface and move it around
Result from solar energy and gravity (wind, flowing water)
Weathering – Processes that break rocks down into smaller pieces
Plays key role in soil formation
Different kinds of rock will result in different soil properties

13. Volcanoes Release Molten Rock from the Earth’s Interior
Volcanoes are simply vents in the earth's surface through which lava and other volcanic products erupt.

14. Earthquakes Are Geological Rock-and-Roll Events
The sudden release of energy stored up by the movement of tectonic plates
Energy travels as seismic waves, each with own type of movement and speed.
P-wave
S-wave
Surface
waves

15. 14-2 How Are the Earth’s Rocks Recycled?
Concept The three major types of rocks found in the earth’s crust—sedimentary, igneous, and metamorphic—are recycled very slowly by the process of erosion, melting, and metamorphism.

16. There Are Three Major Types of Rocks
A very slow geochemical cycle involves three types of rock found in the earth’s crust:
Igneous rock (granite, pumice, basalt)
Solidified lava or magma
Sedimentary rock (sandstone, limestone, shale)
Fusion of eroded sediments
Metamorphic rock (slate, marble, quartzite)
Application of heat / pressure

17. Natural Capital: The Rock Cycle Is the Slowest of the Earth’s Cyclic Processes

18. 14-3 What Are Mineral Resources, and what are their Environmental Effects?
Concept 14-3A Some naturally occurring materials in the earth’s crust can be extracted and made into useful products in processes that provide economic benefits and jobs.
Concept 14-3B Extracting and using mineral resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil.

19. We Use a Variety of Nonrenewable Mineral Resources
Mineral – naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal crystal structure.
Mineral resource (Ore) – a deposit of minerals that can be extracted and processed into useful materials at an affordable cost.
Deposits of nonrenewable mineral resources in the earth’s crust vary in their abundance and distribution.
High Grade Ore – high percentage of desired mineral
Low Grade Ore – low percentage of desired mineral

20. We Use a Variety of Nonrenewable Mineral Resources
Examples of nonrenewable metal and nonmetal mineral resources:
Aluminum – beverage cans, motor vehicles, aircraft
Steel (alloy of iron and other elements) – buildings
Copper – electrical and communications wiring
Platinum – electrical equipment, industrial catalyst
Gold – electrical equipment, jewelry, medical implants
Sand – glass, bricks, concrete
Limestone, - road rock, concrete, cement
Manganese, Cobalt, Chromium – light bulbs, computers, automobiles, aircraft, etc.

21. Concentration of Minerals in Earth’s Crust
Aluminum ~8%
Iron ~5.8%
most Fe and Al is in silicate minerals (like sand) and is, therefore, not used as an ore
Titanium %
Nickel %
Zinc %
Copper %
Lead %
Uranium %
Silver %
Gold %

22. Classification of Nonrenewable Mineral Resources
The U.S. Geological Survey classifies mineral resources into four major categories:
Identified: 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

23. The Life Cycle of a Metal Resource
The extraction, processing, and use of mineral resources has a large environmental impact.
Mining of low grade ore requires more energy, water, and produces more waste.

24. Extracting, Processing, Using Nonrenewable Mineral and Energy Resources

25. Geology and Nonrenewable Minerals
Chapter 14
PART 2

26. There Are Several Ways to Remove Mineral Deposits
Minerals are removed through methods that vary widely in their costs, safety factors, and levels of environmental harm.
The method used is based on mineral depth
Surface mining: shallow deposits are removed
Open pit mining
Strip mining
Subsurface mining: deep deposits are removed
Underground shafts and/or tunnels

27. There Are Several Ways to Remove Mineral Deposits…Surface Mining
Open Pit Mining
Machines dig holes and remove ores, coal, sand, gravel, and stone.
Toxic groundwater can accumulate at the bottom.
World’s deepest diamond mine
- Mirny, Siberia

28. There Are Several Ways to Remove Mineral Deposits…Surface Mining
Strip Mining: Area Strip Mining
Earth movers strips away overburden in order to remove the mineral deposit.
Often leaves highly erodible hills of rubble called spoil banks.
When the ore is dredged from rivers or streams, the unused piles are called tailings.

29. There Are Several Ways to Remove Mineral Deposits…Surface Mining
Strip Mining: Contour strip mining
When mining hilly or mountainous terrain
Terraces are created
As workers move up the slope, the spoils are dumped on the terrace below

30. There Are Several Ways to Remove Mineral Deposits…Surface Mining
Sometimes whole mountain tops are stripped away to get to the ore below – Mountain-top removal
This is a common practice for coal mining in Appalachian mountains

31. There Are Several Ways to Remove Mineral Deposits…Subsurface Mining
Subsurface mining – shafts and tunnels are used to get to ore that is buried much deeper below the surface.
A variety of configurations are used, depending on the situation.

32. There Are Several Ways to Remove Mineral Deposits
Surface Mining
Surface mining
Cheap
Safe for miners
Large environmental destruction
Subsurface mining
Expensive
Hazardous for miners
Less environmental damage
Subsurface Mining
Mining Animation/Virtual Tour:

33. Mining Has Harmful Environmental Effects
Scarring and disruption of the land surface
Piles of mine spoils and tailings
(99% of mined material is waste material)
Subsidence
Loss of rivers and streams
Disruption of ground water flow patterns
Acid Mine Drainage - sulfuric acid produced through weathering of iron sulfide in tailings
4FeS2 + 14H2O = 4Fe(OH)3 + 8H2SO4
Major pollution of water and air
Contamination from heavy metals in mine tailings
e.g. arsenic, mercury

34. Reclamation, or Ecological Restoration
Reclamation – an attempt to return mined land back to its original state (or at least a functional ecosystem)
Recreation
Commercial use
Active mining site
Reclamation process has begun

35. Removing Metals from Ores Has Harmful Environmental Effects
Ore extracted by mining has two parts:
The Ore mineral which is the desired metal
The Gangue (“gang”), or waste material
Smelting – heating ore to release the metal
Chemical solvents can be used as well
Huge amounts of air and water pollution is produced
Contaminated water or toxic sludge sits around in large pools or lagoons

36. 14-4 How Long Will Supplies of Nonrenewable Mineral Resources Last?
Concept 14-4A All nonrenewable mineral resources exist in finite amounts, and as we get closer to depleting any mineral resource, the environmental impacts of extracting it generally become more harmful.
Concept 14-4B An increase in the price of a scarce mineral resource can lead to increased supplies and more efficient use of the mineral, but there are limits to this effect.

37. Mineral Resources Are Distributed Unevenly
Most of the nonrenewable mineral resources are supplied by the United States, Canada, Russia, South Africa, and Australia
The United States, Germany, and Russia (8% of the world’s population) consume about 75% of the world’s widely used metals.
Strategic metal resources – minerals essential for a country’s economic and military strength
Manganese, Cobalt, Chromium, and Platinum
The U.S. has little or no reserves of these metals

38. Supplies of Nonrenewable Mineral Resources Can Be Economically Depleted
Future supply depends on:
Actual or potential supply of the mineral
Rate at which it is used
A rising price for a scarce mineral resource can increase supplies and encourage more efficient use.
Aluminum
Gold
When it becomes economically depleted – costs more to extract/process a mineral than what its worth:
Recycle or reuse existing supplies, waste less, use less, find a substitute, do without

39. Natural Capital Depletion: Depletion Curves for a Nonrenewable Resource
Depletion time - The time it takes to use up a certain proportion (usually 80%) of the mineral reserves at a given rate of use
Dashed vertical lines represent times when 80% depletion occurs.

40. Mining Legislation U.S. General Mining Law of 1872
Encouraged mineral exploration and mining of hard-rock minerals (gold, silver, copper, nickel) on U.S. public lands
Developed to encourage settling the West (1800s)
Until 1995, land could be bought for 1872 prices
Estimated $285 billion of mineral resources now owned/ controlled by private companies, 1/5 are foreign.
Surface Mining Control and Reclamation Act of 1977
Requires the reclamation of land surfaced mined for coal. There are no laws to control or reclaim lands from other types of mines, like hard-rock, etc.

41. 14-5 How Can We Use Mineral Resources More Sustainability?
Concept We can try to find substitutes for scarce resources, reduce resource waste, and recycle and reuse minerals.

42. Solutions: Sustainable Use of Nonrenewable Minerals