1. Environmental Geology
DYNAMIC PLANET

2. A Layered Sphere 3 major concentric zones Crust, Mantle, & Core
CRUST = 1) continental crust & 2) oceanic crust (8 elements make up ~99% of the earth’s crust
MANTLE = largest zone; solid; rich in iron (abundant)
CORE = inner core (solid) & outer core (liquid); made mostly of iron

3. Two main types of movement occur in the asthenosphere:
INTERNAL & EXTERNAL EARTH PROCESSES
Geologic changes originating from the earth’s interior are called internal processes – that build the earth’s surface
Two main types of movement occur in the asthenosphere:
1) Convection cells – large volumes of heated rock moving in a pattern
2) Mantle plumes – rock flows upward as if in a column and then radiates outward

4. Tectonic Processes
Plates (100km thick) are composed of the crust and the outermost part of the mantle (top of the asthenosphere) known as the lithosphere. Plates move approximately 2-15cm/year.

5. Tectonic Processes

6. Constructive (sea floor spreading) Destructive (subduction zones)
Lateral Sliding
Constructive (sea floor spreading)
Destructive (subduction zones)
Conservative
Ridges/Rifts
Trenches
No major impact
Yes
Yes No
Ridges/Rifts
Volcanoes
Earthquakes
Trench

7. GEOLOGIC HAZARDS
Earthquakes - Sudden movements of the earth’s crust that occur along faults where one rock mass slides past another. (Transform Fault Boundary)
Gradual movement - creep.
When friction prevents creep, stress builds up until eventually released with a sudden jerk.
Frequently occur along subduction zones
Tsunami - Seismic sea swells.

8. Volcanoes
Volcanoes and undersea magma vents are the sources of most of the earth’s crust.
Many of world’s fertile soils are weathered volcanic material.
Human / Environmental Dangers
Volcanic Ash
Mudslides
Sulfur Emissions

9. HAWIIAN VOLCANO SYSTEM
MT. ST. HELENS

10. Pangea
Geologists suggest that several times in earth’s history most, or all, of the continents gathered to form a single super-continent, Pangea, surrounded by a single global ocean.

11. INDIA-AUSTRALIAN PLATE SOMALIAN SUBPLATE
EURASIAN PLATE
NORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CARIBBEAN PLATE
CHINA SUBPLATE
ARABIAN PLATE
AFRICAN PLATE
PHILIPPINE PLATE
PACIFIC PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
INDIA-AUSTRALIAN PLATE
SOMALIAN SUBPLATE
Figure 15.4
Natural capital: 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 from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on?
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 15-4a, p. 338

13. Plate Activity….helps? Recycle: Divergent Evolution Rock Cycle
Primary and Secondary Successsion
Minerals-distribution and creation
Divergent Evolution

14. ROCKS AND MINERALS
A mineral is a naturally occurring, inorganic, solid element or compound with a definite chemical composition and regular internal crystal structure.
A rock is a solid, cohesive, aggregate of one or more minerals.
Each rock has a characteristic mixture of minerals, grain sizes, and ways in which the grains are held together.

15. Minerals Most nonrenewable
Single Elements (Au, Ag, C) Compounds (SiO2, NaCl)
Fossil Fuels-Coal, oil, natural gas
Metallic minerals
Nonmetallic- (sand/quartz)

16. Identified
Undiscovered Nanotech pg 335
Reserves
Uneven distribution

17. Rock Types
Rock Cycle - Cycle of creation, destruction, and metamorphosis.
Three major rock classifications:
Igneous
Sedimentary
Metamorphic

18. Igneous rock Granite, pumice, basalt
Erosion
Transportation
Weathering
Deposition
Igneous rock Granite, pumice, basalt
Sedimentary rock Sandstone, limestone
Heat, pressure
Cooling
Heat, pressure, stress
Magma (molten rock)
Figure 15.8
Natural capital: the rock cycle is the slowest of the earth’s cyclic processes. The earth’s materials are recycled over millions of years by three processes: melting, erosion, and metamorphism, which produce igneous, sedimentary, and metamorphic rocks. Rock from any of these classes can be converted to rock of either of the other two classes, or can be recycled within its own class. QUESTION: List three ways that the rock cycle benefits your lifestyle.
Melting
Metamorphic rock Slate, marble, gneiss, quartzite
Fig. 15-8, p. 343

20. Weathering
Mechanical - Physical break-up of rocks into smaller particles without a change in chemical composition.
Chemical - Selective removal or alteration of specific components that leads to weakening and disintegration of rock.
Oxidation
Sedimentation - Deposition of loosened material.

21. Parent material (rock)
Biological weathering (tree roots and lichens)
Chemical weathering (water, acids, and gases)
Physical weathering (wind, rain, thermal expansion and contraction, water freezing)
Figure 15.6
Natural capital: physical, chemical, and biological processes can weather or convert rock into smaller fragments and particles. It is the first step in soil formation.
Particles of parent material
Fig. 15-6, p. 340

22. Sedimentary Rock
Deposited materials that remain in place long enough, or are covered with enough material for compaction, may again become rock.
Formed from crystals that precipitate out of, or grow from, a solution.
Shale
Dolomite
Sandstone
Limestone (calcium carbonate)

23. Metamorphic Rock
Pre-existing rocks modified by heat, pressure, and chemical agents.
Chemical reactions can alter both the composition and structure of rocks as they are metamorphosed.
Marble (from limestone)
Quartzite (from sandstone)
Slate (from mudstone and shale)

24. Igneous Rocks Most common type of rock in earth’s crust.
Solidified from magma extruded onto the surface from volcanic vents.
Quick cooling of magma produces fine-grained rocks.
Basalt
Slow cooling of magma produces coarse-grained rocks.
Granite

26. Mining 1.) Surface Mining: 90% nonfuel, 60% coal -open pit
-strip mining: contour/mountian top removal-Clean Water Act
Surface Mining Control and
Reclamation Act 1977
2.)Subsurface Mining
Higher grade orelower grade
Subsidence
¾ of solid wastes=MINING

28. Undisturbed land Overburden Highwall Coal seam Overburden Pit Bench
Figure 15.13
Natural capital degradation: contour strip mining of coal used in hilly or mountainous terrain.
Spoil banks
Fig , p. 346

29. Fig. 15-9, p. 344 Surface mining Metal ore
Separation of ore from gangue
Smelting
Melting metal
Conversion to product
Discarding of product (scattered in environment)
Figure 15.9
Natural capital degradation: life cycle of a metal resource. Each step in this process uses large amounts of energy and produces air and water pollution and huge amounts of crushed rock and other forms of solid waste. The lower the grade of ore, the greater these environmental impacts.
Recycling
Fig. 15-9, p. 344

30. 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
Transportation, purification, manufacturing
Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat
Use
Figure 15.10
Natural capital degradation: some harmful environmental effects of extracting, processing, and using nonrenewable mineral and energy resources. The energy required to carry out each step causes additional pollution and environmental degradation.
Transportation or transmission to individual user, eventual use, and discarding
Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat
Fig , p. 344

31. Mine, use, throw away; no new discoveries; rising prices
Recycle; increase reserves by improved mining technology, higher prices, and new discoveries B
Production
Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries C
Figure 15.16
Natural capital depletion: depletion curves for a nonrenewable resource (such as aluminum or copper) using three sets of assumptions. Dashed vertical lines represent times when 80% depletion occurs.
Present
Depletion time A
Depletion time B
Depletion time C
Time
Fig , p. 348

32. Getting More Minerals from the Ocean
Hydrothermal deposits form when mineral-rich superheated water shoots out of vents in solidified magma on the ocean floor.
Figure 15-17

33. 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.
Figure 15.18
Solutions: ways to achieve more sustainable use of nonrenewable mineral resources. QUESTION: Which two of the solutions do you think are the most important?
• Have the mineral-based wastes of one manufacturing process become the raw materials for other processes.
• Sell services instead of things.
• Slow population growth.
Fig , p. 351

34. Parent material – baseline beginning of the bedrock that lies below
SOIL LAYERS
Soil is formed by the weathering of rocks, deposition of sediment by erosion, and decomposition of organic material by microorganisms
Leaf litter layer – leaves, animal waste, insects & decomposers; typically dark brown or black in color (organic content)
Topsoil – humus (decomposed organic matter; porous; inorganic minerals; root systems; insects & decomposers
Subsoil – inorganic matter; broken down rock mixture of sand, silt, clay, and gravel
Parent material – baseline beginning of the bedrock that lies below

35. Simplified Soil Food Web

36. Soil texture determines porosity and permeability
Water
High permeability
Low permeability
Fig , p. 224
Infiltration – downward movement of water through soil (percolation)
Leaching – as water seeps down it dissolves soil components (nutrients) in upper layers & carries it to lower layers
Soil texture determines porosity and permeability
100%clay
Increasing
percentage silt
percentage clay 20 40 60 80
100%sand
100%silt
Increasing percentage sand
Loam – roughly equal mixtures of clay, sand, silt, and humus (best soil for growing most crops)

37. pH of the soil impacts the ability of nutrients by plants
PROPERTIES OF SOILS
Texture Nutrient Infiltration Water-Holding Aeration Tilth
Capacity Capacity
Clay Good Poor Good Poor Poor
Silt Medium Medium Medium Medium Medium
Sand Poor Good Poor Good Good
Loam Medium Medium Medium Medium Medium
pH of the soil impacts the ability of nutrients by plants
If soil is too acidic lime is sometimes but it accelerates decomposition of organic matter so more organic fertilizer will also be used to maintain fertility
In arid regions that have alkaline soils sulfur may be added which will slowly be converted to sulfuric acid by bacteria