1. Unit 5: Part I Geologic Processes1

2. Key Concepts of Geology for the AP Exam
Earth’s Geologic History
Earth’s Structure & Composition
Plate Tectonics & Boundaries/Movements
Volcanic Activity & Hotspots
Earthquakes
Weathering & Erosion
The Rock Cycle 2

3. EARTH’S HISTORY
*Availability of Earth’s resources was determined when the planet was formed and cooled*
4.6 Billion years ago, after the birth of the star called Sun, dust and rocks accumulated in a spherical mass. Early Earth was a hot, boiling sea of magma where heat had been generated by the collisions of smaller rock that collided and clumped together
Oldest rocks geologists have been able to find are 3.9 billion years old.
Collisions tapered off, Earth began to cool and a thin crust formed at the surface.

4. Earth’s History
As the cooling continued, water vapor began to escape and condense in the earth's early atmosphere, forming clouds and rain.
This water would cool the surface further until it was flooded with water, forming the seas.
As Earth rotated, heavier elements like Iron were pushed towards the center and the lighter elements like Silicon remained closer to the surface.
Earth is dynamic and ever-changing:
New mountains form, old ones wear down, volcanoes melt and reshape new crust

5. Ole Ally Weg (Not an actual nickname)
German physicist &
Climatologist
Proposed “Continental Drift
Theory” in 1912
Large landmasses fit like
a puzzle
Similar rock structures
Identical plant fossils on
coasts of “matching
continents”
His theory is now called
“Theory of Plate Tectonics”

6. Pangea

7. The Tectonic Cycle Theory of Plate Tectonics PRODUCES:
VOLCANOES and EARTHQUAKES
OCEANIC RIDGE SYSTEM
MOUNTAINS & TRENCHES
TRENCHES

8. The Earth Is a Dynamic Planet
GEOLOGY: Dynamic Processes occurring on Earth’s surface and interior
Three major concentric zones
Core – solid inner core and liquid outer core
Mantle- middle
Includes the ASTHENOSPHERE (partly melted flowing rock)
Crust-
Continental crust (Granite)
Oceanic crust (Basalt): 71% of crust 8

9. Earth’s Vertical Zonation

10. 1. Oceanic crust – floor of deep ocean basins
Lithosphere - Earth’s crust & upper mantle
Thickness varies from 10 to 200 km
1. Oceanic crust – floor of deep ocean basins
Composed of basalt (igneous). Also iron, magnesium and calcium.
Thin (4-5 km) and young.
2. Continental crust -- forms continents.
Composed of granite (igneous). Also silicon, aluminum, sodium and potassium.
Thickness 35 to 70 km.
Old crust.

11. The Lithosphere
The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere.

12. The Crust
The crust is composed of two rocks. The continental crust is mostly granite. The oceanic crust is basalt. Basalt is much denser than the granite. Because of this, the less dense continents ride on the denser oceanic plates.

13. The Mantle
The Mantle is the largest layer of the Earth. The middle mantle is composed of very hot dense rock that flows like asphalt under a heavy weight. The movement of the middle mantle (asthenosphere) is the reason that the crustal plates of the Earth move.

14. Convection Currents
The middle mantle "flows" because of convection currents. Convection currents are caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again --repeating this cycle over and over.

15. Convection Currents
The next time you heat anything like soup or water in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the asthenosphere they also move the crust. The crust gets a free ride with these currents, like the cork in this illustration.

16. The Outer Core
The core of the Earth is like a ball of very hot metals. The outer core is so hot that the metals in it are all in the liquid state. The outer core is composed of the melted metals of nickel and iron.

17. The Inner Core
The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place like a solid. (Ni, Fe, Au, Pt and U)

18. Mantle (asthenosphere)
Volcanoes
Folded mountain belt
Abyssal floor
Oceanic ridge
Abyssal floor
Abyssal hills
Trench
Craton
Abyssal plain
Oceanic crust (lithosphere)
Abyssal plain
Continental shelf
Continental slope
Continental rise
Mantle (lithosphere)
Continental crust (lithosphere)
Mantle (lithosphere)
Figure 14.2
Major features of the earth’s crust and upper mantle. The lithosphere, composed of the crust and outermost mantle, is rigid and brittle. The asthenosphere, a zone in the mantle, can be deformed by heat and pressure.
Mantle (asthenosphere)

19. PLATES BOUNDARIES & MOVEMENT
Move at about the rate a fingernail grows

20. Collision between two continents
Spreading center
Ocean trench
Oceanic tectonic plate
Oceanic tectonic plate
Plate movement
Collision between two continents
Plate movement
Tectonic plate
Subduction zone
Oceanic crust
Oceanic crust
Continental crust
Continental crust
Cold dense material falls back through mantle
Material cools as it reaches the outer mantle
Mantle convection cell
Hot material rising through the mantle
Figure 14.3
The earth’s crust is made up of a mosaic of huge rigid plates, called tectonic plates, which move very slowly across the asthenosphere in response to forces in the mantle. See an animation based on this figure at CengageNOW™.
Two plates move towards each other. One is subducted back into the mantle on a falling convection current.
Mantle
Hot outer core
Inner core
Fig. 14-3, p. 346

21. m EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
CARIBBEAN PLATE
PHILIPPINE PLATE
ARABIAN PLATE
AFRICAN PLATE
INDIA PLATE
PACIFIC PLATE
PACIFIC PLATE
COCOS PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
AUSTRALIAN PLATE
SOMALIAN SUBPLATE
Figure 14.4
The earth’s major tectonic plates. See an animation based on this figure at CengageNOW. Question: What plate are you riding on?
SCOTIA PLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 14-4, p. 347

24. Transform Fault Boundaries
2 plates SLIDE PAST one another
Example: San Andreas Fault

25. The San Andreas Fault as it crosses part of the Carrizo Plain in California, U.S.25

27. Convergent Plate Boundaries
2 Plates COLLIDE
Crust is destroyed and recycled back into Earth’s interior as one of the plates dives under another
Called SUBDUCTION ZONES
VOLCANOES & MOUNTAINS found here
Three types of convergent boundaries
1. Oceanic-Oceanic
2. Oceanic-Continental
3. Continental-Continental

28. Convergent Boundaries
Oceanic meets Oceanic: 2 oceanic plates converge; one is usually subducted under the other and in the process a deep oceanic trench is formed.
Example: The Marianas Trench (Phillipine Plate subducting under the Pacific Plate)
Also forms undersea volcanoes that lead to the formation of island chains
Oceanic meets Continental: Oceanic plate pushes into and subducts under (more dense) a continental plate, the overriding continental plate is lifted up and a mountain range is created.
Ex: Andes Mountains (Oceanic Nazca plate subducted under South American plate)
Continental meets Continental : 2 continental plates meet, neither is subducted because the continental rocks are equally dense. Instead, the crust tends to buckle and be pushed upward or sideways.
Example: The Himalaya Mountain chain (Eurasian plate crumples and overrides the Indian plate)
Example: Appalachian Mountains (North American, Eurasian, & African plates)

29. Convergent Plates: Mt. Everest

30. Everest (Not the University)
Mt Everest is the tallest mountain
At 29,029 ft (That is 5.5 MILES!)
It grows inches higher every year
Everest is part of the Himalaya mountain range along the border of Nepal and Tibet.
At 9,800 feet, for example, there's about 2/3 of the oxygen in the air than at sea level. At 20,000 ft, there is roughly half the oxygen content in the air. At 29,035ft, the summit of Everest, there is only a third of the oxygen in the air.

31. Convergent Boundaries: Andes Mountains (Peru)

32. Divergent Plate Boundaries
Form ridges in ocean (ex: Mid-Atlantic Ridge)
North American & Eurasian plate diverging
Form rifts on land (ex: Great African Rift Valley)

33. Divergent Plates: Building New Crust

34. Divergent Boundary: Mid-Atlantic Ridge System

35. Divergent Boundary: Africa’s Great Rift Valley

36. Earth’s Surface Builds Up and Wears Down
Internal geologic processes build up the surface
External geologic processes (driven by the sun and influenced by gravity)
Weathering (key in soil formation)
Physical, Chemical, and Biological processes that break down rock
Erosion
Wind, Water, Human Activities
Glaciers- (formed the Great Lakes) 36

37. 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 14.6
Weathering: Biological, chemical, and physical processes weather or convert rock into smaller fragments and particles. It is the first step in soil formation.
Particles of parent material
Fig. 14-6, p. 348

38. Volcanoes: Molten Rock Release from Interior
A fissure (vent or crack) in Earth’s surface that releases molten rock from the interior.
Magma (molten rock beneath the surface)
Lava (molten rock above the surface)
Usually found in areas with earthquake activity
Benefits:
Form mountains, lakes, islands, fertile soil 38

39. Volcanic Ash Consists of rock fragments, minerals, gas
Formed from dissolved gas in magma being released violently
Number of negative effects
Can change local climates by preventing solar radiation from reaching Earth’s surface
Reduce crop yields

40. Partially molten asthenosphere
Extinct volcanoes
Eruption cloud
Ash
Acid rain
Ash flow
Lava flow
Mud flow
Central vent
Landslide
Magma conduit
Magma reservoir
Figure 14.7
A volcano is created when magma in the partially molten asthenosphere rises in a plume through the lithosphere to erupt on the surface as lava, which builds a cone. Sometimes, internal pressure is high enough to cause lava, ash, and gases to be ejected into the atmosphere or to flow over land, causing considerable damage (Concept 14-1B). Chains of islands have been created by volcanoes that erupted and then became inactive.
Solid lithosphere
Upwelling magma
Partially molten asthenosphere
Fig. 14-7, p. 349

41. AGHHHHHHHH RUN

42. Mount St. Helens (1980)
1980-Eruption

43. Mount Pinutubo (Phillippines-1991)

44. Tectonic Activity

45. EARTHQUAKES Earthquake Terminology (MUST KNOW THESE TERMS)
Seismic waves- vibrations caused by earthquakes
Focus : Point of initial movement
Epicenter: Point on the surface above the focus
Magnitude – amount of energy released
Amplitude – size of seismic waves 45

46. Earthquakes
Earthquakes caused by stress in crust which deforms rock until it fractures producing faults.
This faulting or abrupt movement causes EARTHQUAKES

47. Earthquakes
Richter scale – a logarithmic scale recorded by a seismograph.
Measures the amplitudes of the waves produced.
Ex: An earthquake of magnitude 5 has 10X more ground shaking than a magnitude of 4.
It is the energy that knocks down buildings and causes damage.
Insignificant: <4.0
Destructive: 6.0–6.9
Major: 7.0–7.9
Great: >8.0 47

48. Liquefaction of recent sediments causes buildings to sink
Two adjoining plates move laterally along the fault line
Earth movements cause flooding in low-lying areas
Landslides may occur on hilly ground
Figure 14.8
Major features and effects of an earthquake, one of nature’s most powerful events.
Shock waves
Focus
Epicenter
Fig. 14-8, p. 350

49. Earthquakes
AFTERSHOCKS– smaller earthquakes that follow – often over a period of months
FORESHOCKS – seconds to weeks before the main shock
PRIMARY EFFECTS - shaking, sometimes permanent vertical or horizontal displacement of earth
SECONDARY EFFECTS - rock slides, fires, flooding, tsumanis 49

50. Earthquakes Can Cause Landslides
Mass wasting
Slow movement or
Fast movement
Rockslides
Avalanches
Mudslides
1970, earthquake in Peru caused massive landslide that killed 17,000 people 50

51. Quake Risk in the USA 51

52. What about in GA?

53. Quake Risk Worldwide 53

54. Interesting Facts There are over 1 million eq a year
There are over 10,000 eq in California a year.
San Andreas Fault is over 800 miles long.

55. Tsunamis Caused by earthquakes in the sea Tsunami (tidal wave)
Can travel as fast as a jet plane
Detection of tsunamis by buoys 55

56. Undersea thrust fault Upward wave Bangladesh India Burma Thailand
Earthquake in seafloor swiftly pushes water upwards, and starts a series of waves
Waves move rapidly in deep ocean reaching speeds of up to 890 kilometers per hour.
As the waves near land they slow to about 45 kilometers per hour but are squeezed upwards and increased in height.
Waves head inland causing damage in their path.
Undersea thrust fault
Upward wave
Bangladesh
India
Burma
Figure 14.11
Formation of a tsunami and map of area affected by a large tsunami in December 2004.
Thailand
Malaysia
Sri Lanka
Earthquake
Indonesia
Sumatra
December 26, 2004, tsunami
Fig , p. 352

57. 2004: Indonesia Tsunami December 26, 2004: Indian Ocean
Magnitude of 9.15 earthquake
Waves as high as 100 feet, 228,000 were killed
Coral reefs and mangrove forests reduce wave impact. (mangrove forests had been cleared and many reefs have been damaged in last 30 years)

58. Indonesian Shoreline Before and After58

59. 2011: Japanese Tsunami March 11, 2011: Tohoku Earthquake and Tsunami
Occurred off coast of Japan
9.3 magnitude; 20 miles under water
133 foot waves
Additional Complication: Nuclear Power Facility

60. The Rock Cycle
Concept 3 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. 60

61. Minerals
Either an ELEMENT or INORGANIC COMPOUND – naturally occurring and a solid
Some are single elements – Au, Ag
Most are compounds – mica, salt, quartz

62. ROCKS
Any material that makes up a large natural continuous part of the earth’s crust
Can contain only one mineral but most consist of two or more minerals
Example: GRANITE – quartz, mica, and feldspar

63. 3 Types of Rocks Sedimentary Made of sediments-
clastic -cemented and compacted chemical- made from dissolved minerals like limestone and rock salt)
Sandstone and shale (compacted sediments)
Dolomite and limestone (compacted shells and skeletons)
Lignite and bituminous coal (compacted plant remains) 63

64. 3 Types of Rocks Igneous – forms the bulk of earth’s crust
Granite (formed underground)
Pumice
Obsidian
Basalt
Metamorphic –formed by heat and pressure
Anthracite from coal
Slate from shale
Marble from limestone
Gneiss from granite 64

65. IGNEOUS ROCKS FORMS FROM MOLTEN ROCK MATERIAL (MAGMA) FORMS FROM LAVA
Wells up from upper mantle or deep crust
Cools
Hardens into rock – EXAMPLE: GRANITE
FORMS FROM LAVA
Forms above ground when magma coold
Main part of earth’s crust
Source of many nonfuel mineral resources

66. The Rock Cycle

67. The Rock Cycle