Earth is a Dynamic and Evolving Planet

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Earth is a Dynamic and Evolving Planet

• changes in its surface

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3 Main Themes
Plate Tectonics
Evolution
Uniformitarianism
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Uniformitarianism

• Uniformitarianism is a cornerstone of geology
• present-day processes have operated throughout
  geologic time
• physical and chemical laws of nature have
  remained the same through time
• to interpret geologic events
• we must first understand present-day processes
  and their results
• rates and intensities of geologic processes may
  have changed with time

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Historical Geology

• In historical geology we study
• changes in our dynamic planet
• how and why past events happened
• implication for todays global ecosystems
• Principles of historical geology
• aid in interpreting Earths history
• also have practical applications

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Geologic Time

• Human perspective
• seconds, hours, days, years
• Ancient human history
• hundreds or even thousands of years
• Geologic history
• millions, hundreds of millions, billions of years

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Geologic Time Scale

• Resulted from the work of many 19th century
  geologists who
• pieced together information from numerous rock
  exposures
• constructed a sequential chronology based on
  changes in Earths biota through time
• started as a relative time scale
• The time scale was subsequently dated in years
  using radiometric dating techniques

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Geologic Time Scale
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How Does the Study of Historical Geology Benefit
Us?

• Survival of the human species depends on
  understanding how Earths various subsystems work
  and interact
• how we consume natural resources and interact
  with the environment determines our ability to
  pass on this standard of living to the next
  generation
• our standard of living depends directly on our
  consumption of natural resources that formed
  millions and billions of years ago
• Study what has happened in the past, on a global
  scale, to try and determine how our actions might
  affect the balance of subsystems in the future