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GEOLOGY AND THE
ENVIRONMENT
The Walker School
Environmental Science
Earth’s Principal Systems
   Atmosphere
   Hydrosphere
   Biosphere
   Lithosphere
   Magnetosphere
   Cryosphere
Interaction Among Earth’s Systems




                                Table 1-1, p. 4
Earth is a Dynamic Planet
   Geologic Hazards
   Renewable Soil
   Nonrenewable
    Minerals
   Energy Resources



  ...
WHAT IS THE EARTH’S
STRUCTURE?
Earth’s Structure



                    The Moho, is the
                    boundary between the
                    Ear...
Seismic S & P Waves




                      Seismic waves
                      provide evidence
                      t...
Internal Processes
   Convection Cells
   Mantle Plumbs
    (upwellings)
   Plutonic Bodies
Plutonic Bodies



L: inflated sills.
                                    B: > 100 km2




 Internal Processes
           ...
Volcanic Bodies




External Processes
Mantle Plumbs and Interplate Hotspots

                           Mantle plumbs are
                           stationary,...
Volcanic National Park, HI
     http://www.nps.gov/havo/




Most geographically isolated group of islands on
Earth; featu...
WHAT IS PLATE
TECTONICS?
Earth’s crust is about 5% of it’s mass.
Earth has 15 Major Plates




                            Fig. 1-11, p. 17
Environmental Role of Plate Movement

   Changes Climate
   Stimulates Evolution
   Changes Migratory
    Patterns

   ...
Major Features of the Earth’s Crust

  Abyssal




                                     Abyssal plain
                    ...
Connections, Plates and Earth Systems




                                  Table 1-3, p. 18
Convergent Plates




                    Primarily responsible
                    for mountain building
                ...
Continental Crust

                    Composed of many rock
                    types.

                    Can be as old...
Grand Teton National Park, WY
http://www.nps.gov/grte




                                        The Grand Tetons are one...
Alpine Climate Zones

 Altitude
            Mountain
            Ice and snow

            Tundra (herbs,
            lich...
Divergent Plates


Builds new crust.




                    Atlanta Ocean is
                    getting bigger,
        ...
Mid-Atlantic Ridge & Iceland




                 One of the few places on earth that a
                 divergent pate is...
Divergent Plates Rift to Form Oceans




Rifting between the African
and Arabian Plate formed
the Red Sea.
               ...
Stages of Ocean
Basin Formation
Oceanic Crust
                5 to 8 km thick.

                Composed mainly of basalt and
                gabbro.

   ...
Costal Features
                                                    Lake
                                          Glacier...
WHAT GEOLOGIC PROCESSES
OCCUR ON THE EARTH’S SURFACE?
Weathering vs. Erosion
   Weathering the decomposition of earth rocks, soils
    and their minerals through direct contac...
Formation of the Grand Canyon
http://www.youtube.com/watch?v=ktf73HNZZGY




                                             ...
Arches National Park
http://www.nps.gov/arch/National


                                   Erosion takes place
           ...
Hoodoos, Bryson Canyon National Park
http://www.nps.gov/brca/
Types of Weathering
   Mechanical
   Chemical
   Biological


                 Weathering of Granite




              ...
Physical Weathering
   Mechanical or physical
    weathering involves the
    breakdown of rocks and
    soils through di...
Chemical Weathering
   Chemical weathering,
    involves the direct effect
    of atmospheric
    chemicals, or
    biolo...
Biological Weathering from Plants

Trees and other plants in
Lassen Volcanic National Park,
CA help break down parent
mate...
Salt Weathering (haloclasty)
   Mechanical
   Derives from an external source
    (capillary rising ground water,
    eo...
Isotasic Rebound
   from Glaciers




Grosser Aletschgletscher, Switzerland




                                        Fi...
WHY DO EARTHQUAKES
OCCUR?
Earthquakes
   Most occur along subduction zones and strike-slip
    zones
   Some occur in aseismic zones
   Movement ...
Elastic Rebound Theory
   Proposed by Henry F Reid in 1910
   Rocks along a fault move relative to each other and
    ca...
Two adjoining plates
            Liquefaction of      move laterally along
            recent sediments     the fault line...
HOW ARE EARTHQUAKES
MEASURED?
Measurements
   Intensity
   Amplitude
   Duration
Scales
   Richter Scale
       Measurement of energy released for smaller and approximate
        earthquakes
   Surfac...
Seismographic Reading
Seismic Wave and Their Destructive Patterns.
Primary Modes of Destruction
   Consolidation
   Liquefaction
   Vibration



                    Earthquake damage in ...
Secondary Effects of Earthquakes
   Rockslides
   Urban Fires
   Flooding
   Tsunamis
   Building Damage
   Loss of ...
Expected Damage From
Earthquakes

       No damage expected
                            Canada
       Minimal damage

    ...
Global Seismograph Network
http://www.iris.edu/about/GSN/
Indian Ocean Earthquake
http://en.wikipedia.org/wiki/2004_tsunami
Tsunamis
   A series of waves created when a body of water, such as an ocean, is rapidly displaced.
   Earthquakes, mass...
Tsunami Warning System
WHAT ARE VOLCANOES?
Distribution of Volcanoes
   Circum-Pacific
    Belt (60%)
   Mediterranean
    Belt (20%)
   Mid-Oceanic
    Ridges (2...
General Structure
                                                 extinct
                                               ...
Crater Lake, OR Caldera


Caldera Floor of Crater Lake




                               Wizard Island, Crater Lake, OR
Learn About Megavolcanos Around the World
http://www.pbs.org/wgbh/nova/megavolcano/about.html
VOLCANIC MONITORING
Important Monitoring Techniques




                                  Fig. 5-23, p. 159
Fumarole Gas Monitoring
   Chemically-selective sensors
    for SO2 and CO2 measure
    gas concentrations and a wind
   ...
Ground Deformation Monitoring
   Paint
   Electronic Distance Meters
       determine the horizontal movements
        ...
Remote Sensing
   The Advanced Very High
    Resolution Radiometer (AVHRR)
    is a space-borne sensor
    embarked on th...
Primary Effects of Volcanoes
   Pyroclastic Flows
   Fumaroles
   Landslides
   Ash Fall
   Earthquakes
   High Temp...
Secondary Effects of Explosions
   Suffocation from Ash
   Asphyxiation from
    Volcanic Gasses
   Tsunamis
   Temper...
Environmental Effects
   Involved in the formation
    of continental crust and
    offset weathering and
    erosion
  ...
Volcanic Gasses
   Water Vapor
   Carbon Dioxide
   Nitrogen
   Sulfur Dioxide
   Hydrogen Sulfide
   Carbon Monoxid...
Effects of Volcanoes on Climate
   Nucleation, condensation, and sedimentation of aerosols (acid rain)
   Change in Albe...
HYDROTHERMAL VENT
ECOLOGY
Hydrothermal Vents
   Distributes heat and
    drives water circulation
    in the ocean through
    convection
   Provi...
Hydrothermal Vent Ecosystem   The chemosynthetic bacteria
                              grow into a thick mat which
      ...
Location of Major Vent Systems
Hydrothermal Vent Chemistry
Learn More About Vents
http://www.divediscover.whoi.edu/vents/index.html
Geology and the Environment
Geology and the Environment
Geology and the Environment
Geology and the Environment
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Transcript of "Geology and the Environment"

  1. 1. GEOLOGY AND THE ENVIRONMENT The Walker School Environmental Science
  2. 2. Earth’s Principal Systems  Atmosphere  Hydrosphere  Biosphere  Lithosphere  Magnetosphere  Cryosphere
  3. 3. Interaction Among Earth’s Systems Table 1-1, p. 4
  4. 4. Earth is a Dynamic Planet  Geologic Hazards  Renewable Soil  Nonrenewable Minerals  Energy Resources Change is the Norm
  5. 5. WHAT IS THE EARTH’S STRUCTURE?
  6. 6. Earth’s Structure The Moho, is the boundary between the Earth's crust and the mantle. The Moho serves to separate both oceanic crust and continental crust from underlying mantle.
  7. 7. Seismic S & P Waves Seismic waves provide evidence that Earth’s internal structure is layered, not homogeneous. Fig. 11-9b, p. 345
  8. 8. Internal Processes  Convection Cells  Mantle Plumbs (upwellings)  Plutonic Bodies
  9. 9. Plutonic Bodies L: inflated sills. B: > 100 km2 Internal Processes S: <100 km2 Fig. 4-24, p. 123
  10. 10. Volcanic Bodies External Processes
  11. 11. Mantle Plumbs and Interplate Hotspots Mantle plumbs are stationary, while the plates move. This activity has caused the creation of new Hawaiian Islands over the past 12 million years. Fig. 2-22, p. 58
  12. 12. Volcanic National Park, HI http://www.nps.gov/havo/ Most geographically isolated group of islands on Earth; features include new cinder cones, glowing pit Lava Tube in Hawaii craters, rivers of lava and fountains of spatter; volcanic features at mass to the lithosphere, water to the hydrosphere, carbon dioxide to the atmosphere, and nutrients for plants. Fig. 5-3a, p. 137
  13. 13. WHAT IS PLATE TECTONICS?
  14. 14. Earth’s crust is about 5% of it’s mass.
  15. 15. Earth has 15 Major Plates Fig. 1-11, p. 17
  16. 16. Environmental Role of Plate Movement  Changes Climate  Stimulates Evolution  Changes Migratory Patterns Scope of the last Ice Age, 1200 BCE
  17. 17. Major Features of the Earth’s Crust Abyssal Abyssal plain Folded mountain belt hills Abyssal Oceanic Abyssal Trench floor ridge floor Craton Volcanoes Continental Oceanic crust rise (lithosphere) Continental Mantle (lithosphere) slope Mantle Continental (lithosphere) shelf Abyssal plain Continental crust Mantle (asthenosphere) (lithosphere) Convection from the Earth’s mantle rises and cools, driving the movement of the plates, which in turn causes the folding of the lithosphere creating mountains and volcanoes.
  18. 18. Connections, Plates and Earth Systems Table 1-3, p. 18
  19. 19. Convergent Plates Primarily responsible for mountain building events. Fig. 2-18c, p. 53
  20. 20. Continental Crust Composed of many rock types. Can be as old as 4 billion years. Varies in thickness from 20 to 80 km. Makes up about 41% of Earth’s surface.
  21. 21. Grand Teton National Park, WY http://www.nps.gov/grte The Grand Tetons are one of the younger mountain ranges on Earth. 24% of the Earth's land mass is mountainous. 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and A mountain is usually produced by the more than half of humanity depends on movement of lithospheric plates, mountains for water. called orogenic movement.
  22. 22. Alpine Climate Zones Altitude Mountain Ice and snow Tundra (herbs, lichens, mosses) Latitude Coniferous Forest Deciduous Forest Tropical Forest Tundra (herbs, Polar ice Tropical Deciduous Coniferous and snow Forest lichens, mosses) Forest Forest
  23. 23. Divergent Plates Builds new crust. Atlanta Ocean is getting bigger, while the Pacific is decreasing in size.
  24. 24. Mid-Atlantic Ridge & Iceland One of the few places on earth that a divergent pate is evident on land.
  25. 25. Divergent Plates Rift to Form Oceans Rifting between the African and Arabian Plate formed the Red Sea. Fig. 2-15, p. 48
  26. 26. Stages of Ocean Basin Formation
  27. 27. Oceanic Crust 5 to 8 km thick. Composed mainly of basalt and gabbro. Not older than 180 million years. Covered with dead organism and sediment, about 1 km thick. Little variability in composition.
  28. 28. Costal Features Lake Glacier Tidal Shallow marine Spits Stream flat environment Barrier Dunes Lagoon islands Delta Dunes Beach Shallow marine environment Volcanic island Coral reef Continental shelf Continental slope Abyssal plain Deep-sea fan Continental rise
  29. 29. WHAT GEOLOGIC PROCESSES OCCUR ON THE EARTH’S SURFACE?
  30. 30. Weathering vs. Erosion  Weathering the decomposition of earth rocks, soils and their minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or quot;with no movementquot;, and thus should not to be confused with erosion, which involves the movement and disintegration of rocks and minerals by agents such as water, ice, wind, and gravity.
  31. 31. Formation of the Grand Canyon http://www.youtube.com/watch?v=ktf73HNZZGY Debris flows shown in this clip erode rock along the walls of the canyon.
  32. 32. Arches National Park http://www.nps.gov/arch/National Erosion takes place at different rates – called differential erosion Produces: hoodoos, spires, arches, and pedestals Fig. 6-CO, pp. 168-169
  33. 33. Hoodoos, Bryson Canyon National Park http://www.nps.gov/brca/
  34. 34. Types of Weathering  Mechanical  Chemical  Biological Weathering of Granite Fig. 6-1a, p. 170
  35. 35. Physical Weathering  Mechanical or physical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions such as heat, water, ice and pressure. Badlands, SD
  36. 36. Chemical Weathering  Chemical weathering, involves the direct effect of atmospheric chemicals, or biologically produced chemicals (also known as biological weathering), Lichens are part fungi and part algae. They in the breakdown of derive their nutrients from the rock and rocks, soils and minerals. contribute to chemical weathering.
  37. 37. Biological Weathering from Plants Trees and other plants in Lassen Volcanic National Park, CA help break down parent material into smaller pieces and contribute to mechanical weathering. Fig. 6-6b, p. 174
  38. 38. Salt Weathering (haloclasty)  Mechanical  Derives from an external source (capillary rising ground water, eolian origin, sea water along rocky coasts, atmospheric pollution).  Favored by dry conditions in arid climates.  The expanding salt crystals exert a pressure on the walls of the rock pores that exceeds the tensile Marine Abrasion of Granite. strength of the rock.
  39. 39. Isotasic Rebound from Glaciers Grosser Aletschgletscher, Switzerland Fig. 11-17, p. 351
  40. 40. WHY DO EARTHQUAKES OCCUR?
  41. 41. Earthquakes  Most occur along subduction zones and strike-slip zones  Some occur in aseismic zones  Movement of magma causes tremors
  42. 42. Elastic Rebound Theory  Proposed by Henry F Reid in 1910  Rocks along a fault move relative to each other and can bend elastically  Energy released from the bending causes shock waves, which emanate from the plane of rupture
  43. 43. Two adjoining plates Liquefaction of move laterally along recent sediments the fault line causes buildings Earth movements of sink cause flooding in low-lying areas Landslides may occur on hilly ground Shock waves Epicenter Focus
  44. 44. HOW ARE EARTHQUAKES MEASURED?
  45. 45. Measurements  Intensity  Amplitude  Duration
  46. 46. Scales  Richter Scale  Measurement of energy released for smaller and approximate earthquakes  Surface Wave Magnitude Scale  Measurement of energy released for extremely large earthquakes at a distance  Moment Magnitude Scale  Estimates the amount of displacement and area of rupture along the fault  Mercalli Scale  Directly describes the intensity of shaking rather than the magnitude  Useful in comparing damage from earthquakes at different locations
  47. 47. Seismographic Reading
  48. 48. Seismic Wave and Their Destructive Patterns.
  49. 49. Primary Modes of Destruction  Consolidation  Liquefaction  Vibration Earthquake damage in a Afghan village.
  50. 50. Secondary Effects of Earthquakes  Rockslides  Urban Fires  Flooding  Tsunamis  Building Damage  Loss of Life
  51. 51. Expected Damage From Earthquakes No damage expected Canada Minimal damage Moderate damage Severe damage United States
  52. 52. Global Seismograph Network http://www.iris.edu/about/GSN/
  53. 53. Indian Ocean Earthquake http://en.wikipedia.org/wiki/2004_tsunami
  54. 54. Tsunamis  A series of waves created when a body of water, such as an ocean, is rapidly displaced.  Earthquakes, mass movements above or below water, some volcanic eruptions and other underwater explosions, landslides, underwater earthquakes, large asteroid impacts and testing with nuclear weapons at sea all have the potential to generate a tsunami.  As the tsunami approaches the coast and the waters become shallow, the wave is compressed due to wave shoaling and its forward travel slows and its amplitude grows enormously, producing a distinctly visible wave.
  55. 55. Tsunami Warning System
  56. 56. WHAT ARE VOLCANOES?
  57. 57. Distribution of Volcanoes  Circum-Pacific Belt (60%)  Mediterranean Belt (20%)  Mid-Oceanic Ridges (20%)  More common along both divergent than convergent plate boundaries.  Mainly composed of intrusive magma flows.  Composed of mafic magma that forms beneath spreading plates.  Pyroclastic materials are not common because lava is fluid.  Water pressure prevents gasses from expanding and escaping. Fig. 5-20, p. 151
  58. 58. General Structure extinct volcanoes central vent magma magma reservoir conduit Solid lithosphere Upwelling magma Partially molten asthenosphere
  59. 59. Crater Lake, OR Caldera Caldera Floor of Crater Lake Wizard Island, Crater Lake, OR
  60. 60. Learn About Megavolcanos Around the World http://www.pbs.org/wgbh/nova/megavolcano/about.html
  61. 61. VOLCANIC MONITORING
  62. 62. Important Monitoring Techniques Fig. 5-23, p. 159
  63. 63. Fumarole Gas Monitoring  Chemically-selective sensors for SO2 and CO2 measure gas concentrations and a wind sensor measures wind speed and direction.  Data from solar-powered stations are transmitted to GOES geostationary satellite and then down to observatories every 10 minutes, providing near real time data on degassing of volcanoes
  64. 64. Ground Deformation Monitoring  Paint  Electronic Distance Meters  determine the horizontal movements that occur on active volcanoes  Tiltmeters  leveling surveys to measure vertical motions  Global Positioning Systems  allows us to measure horizontal motions much more accurately and conveniently, and also to estimate vertical motions in the same survey
  65. 65. Remote Sensing  The Advanced Very High Resolution Radiometer (AVHRR) is a space-borne sensor embarked on the NOAA family of polar orbiting platforms.  The primary purpose of these instruments is to monitor clouds and to measure the thermal emission (cooling) of the Earth.  The main difficulty associated with these investigations is to properly deal with the many limitations of these instruments, especially in the early period (sensor calibration, orbital drift, limited spectral and directional sampling, etc).
  66. 66. Primary Effects of Volcanoes  Pyroclastic Flows  Fumaroles  Landslides  Ash Fall  Earthquakes  High Temperatures
  67. 67. Secondary Effects of Explosions  Suffocation from Ash  Asphyxiation from Volcanic Gasses  Tsunamis  Temperatures Decreases Ash can coat your lungs, causing the formation of a quick cement, asphyxiating you.
  68. 68. Environmental Effects  Involved in the formation of continental crust and offset weathering and erosion  Provide nutrient rich soils  By trapping clouds at their peaks, water for agriculture  Agriculture based Volcanic soils in Sumatra. cultures are attracted to their bases
  69. 69. Volcanic Gasses  Water Vapor  Carbon Dioxide  Nitrogen  Sulfur Dioxide  Hydrogen Sulfide  Carbon Monoxide  Hydrogen  Chlorine Gasses emitted from fumaroles at the Sulfur Works in Lassen Volcanic National Park, CA Fig. 5-2, p. 136
  70. 70. Effects of Volcanoes on Climate  Nucleation, condensation, and sedimentation of aerosols (acid rain)  Change in Albedo from ash cloud  Tropospheric cooling from the addition of sulfur to the stratsophere  Ozone destruction through the formation of atomic chlorine
  71. 71. HYDROTHERMAL VENT ECOLOGY
  72. 72. Hydrothermal Vents  Distributes heat and drives water circulation in the ocean through convection  Provides energy source in the form of hydrogen sulfide to benthic chemotrophs  Distributes minerals and influences the composition of the ocean
  73. 73. Hydrothermal Vent Ecosystem The chemosynthetic bacteria grow into a thick mat which attracts other organisms such as amphipods and copepods which graze upon the bacteria directly. Larger organisms such as snails, shrimp, crabs, tube worms, fish, and octopuses form a food chain of predator and prey relationships above the primary consumers. The main families of organisms found around seafloor vents are annelids, pogonophorans, gastropods, and crustaceans, with large bivalves, vestimentiferan worms, and quot;eyelessquot; shrimp making up the bulk of non- microbial organisms.
  74. 74. Location of Major Vent Systems
  75. 75. Hydrothermal Vent Chemistry
  76. 76. Learn More About Vents http://www.divediscover.whoi.edu/vents/index.html
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