Plate Tectonics and Geology

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Plate Tectonics and Geology

• TEAC 2006
• Teresa Kennedy

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Learning Objectives

• Development and limits of theory of plate
  tectonics
  
• Relationship between tectonic processes,
  earthquakes and volcanoes
  
• Correlation between tectonic processes and type
  of volcano
  
• Overview of geologic and tectonic history of
  Western U.S.

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Theory of Plate Tectonics

• Based on theory of continental drift
• Based on fossil, glacial, and rock type evidence
  (Alfred Wegener, 1915)
  
• Not initially accepted
• Further developed by cast of many over next 50
  years
  
• Strengthened by geophysical evidence including
  magnetics and seismological data
  
• Mechanism of movement still debated

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What happens at Plate Boundaries?

• Correlation between plate boundaries and geologic
  events
  
• Types of boundaries Convergent (colliding),
  Divergent (spreading), and Transform
  (strike-slip)
  
• Type of collision affects resulting landforms
• Volcanoes and plate boundaries

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Geologic Time

• Geologic Time Four major eras
• Precambrian before 544 mya
• Paleozoic 544 mya 250 mya
• Mesozoic 250 mya 65 mya
• Cenozoic 65 mya to present

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Plate Tectonics and Geology

• Earths crust is dynamic, not static
• Crustal motion over time has affected climate,
  rock formations, and resulting landforms and
  landmasses.
  
• Plate Tectonics

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The Western U.S

• Geologic History of Western U.S.
• Observe
• Changing craton shoreline
• Maturing craton landscape
• Oceanic volcanic arcs
• Accreted terranes of California
• Changes in subduction zones along western coast

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San Andreas Fault System