1. GEOLOGY AND THE
ENVIRONMENT
The Walker School
Environmental Science

2. Earth’s Principal Systems
 Atmosphere
 Hydrosphere
 Biosphere
 Lithosphere
 Magnetosphere
 Cryosphere

3. Interaction Among Earth’s Systems
Table 1-1, p. 4

4. Earth is a Dynamic Planet
 Geologic Hazards
 Renewable Soil
 Nonrenewable
Minerals
 Energy Resources
Change is
the Norm

5. WHAT IS THE EARTH’S
STRUCTURE?

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. Seismic S & P Waves
Seismic waves
provide evidence
that Earth’s internal
structure is layered,
not homogeneous.
Fig. 11-9b, p. 345

8. Internal Processes
 Convection Cells
 Mantle Plumbs
(upwellings)
 Plutonic Bodies

9. Plutonic Bodies
L: inflated sills.
B: > 100 km2
Internal Processes
S: <100 km2
Fig. 4-24, p. 123

10. Volcanic Bodies
External Processes

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. 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. WHAT IS PLATE
TECTONICS?

14. Earth’s crust is about 5% of it’s mass.

15. Earth has 15 Major Plates
Fig. 1-11, p. 17

16. Environmental Role of Plate Movement
 Changes Climate
 Stimulates Evolution
 Changes Migratory
Patterns
Scope of the last Ice Age, 1200 BCE

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. Connections, Plates and Earth Systems
Table 1-3, p. 18

19. Convergent Plates
Primarily responsible
for mountain building
events.
Fig. 2-18c, p. 53

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. 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. 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. Divergent Plates
Builds new crust.
Atlanta Ocean is
getting bigger,
while the Pacific is
decreasing in size.

24. Mid-Atlantic Ridge & Iceland
One of the few places on earth that a
divergent pate is evident on land.

25. Divergent Plates Rift to Form Oceans
Rifting between the African
and Arabian Plate formed
the Red Sea.
Fig. 2-15, p. 48

26. Stages of Ocean
Basin Formation

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. 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. WHAT GEOLOGIC PROCESSES
OCCUR ON THE EARTH’S SURFACE?

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. 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. 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. Hoodoos, Bryson Canyon National Park
http://www.nps.gov/brca/

34. Types of Weathering
 Mechanical
 Chemical
 Biological
Weathering of Granite
Fig. 6-1a, p. 170

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. 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. 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. 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.

40. Isotasic Rebound
from Glaciers
Grosser Aletschgletscher, Switzerland
Fig. 11-17, p. 351

41. WHY DO EARTHQUAKES
OCCUR?

42. Earthquakes
 Most occur along subduction zones and strike-slip
zones
 Some occur in aseismic zones
 Movement of magma causes tremors

43. 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

44. 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

45. HOW ARE EARTHQUAKES
MEASURED?

46. Measurements
 Intensity
 Amplitude
 Duration

47. 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

49. Seismographic Reading

50. Seismic Wave and Their Destructive Patterns.

51. Primary Modes of Destruction
 Consolidation
 Liquefaction
 Vibration
Earthquake damage in a Afghan village.

52. Secondary Effects of Earthquakes
 Rockslides
 Urban Fires
 Flooding
 Tsunamis
 Building Damage
 Loss of Life

53. Expected Damage From
Earthquakes
No damage expected
Canada
Minimal damage
Moderate damage
Severe damage
United States

55. Global Seismograph Network
http://www.iris.edu/about/GSN/

56. Indian Ocean Earthquake
http://en.wikipedia.org/wiki/2004_tsunami

57. 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.

58. Tsunami Warning System

59. WHAT ARE VOLCANOES?

60. 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

61. General Structure
extinct
volcanoes
central
vent
magma
magma
reservoir
conduit
Solid
lithosphere
Upwelling
magma Partially molten
asthenosphere

63. Crater Lake, OR Caldera
Caldera Floor of Crater Lake
Wizard Island, Crater Lake, OR

64. Learn About Megavolcanos Around the World
http://www.pbs.org/wgbh/nova/megavolcano/about.html

65. VOLCANIC MONITORING

66. Important Monitoring Techniques
Fig. 5-23, p. 159

67. 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

68. 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

69. 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).

70. Primary Effects of Volcanoes
 Pyroclastic Flows
 Fumaroles
 Landslides
 Ash Fall
 Earthquakes
 High Temperatures

71. 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.

72. 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

73. 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

74. 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

75. HYDROTHERMAL VENT
ECOLOGY

76. 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

77. 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.

78. Location of Major Vent Systems

79. Hydrothermal Vent Chemistry

80. Learn More About Vents
http://www.divediscover.whoi.edu/vents/index.html