Earth Science 202: Take-Away Points

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay

Introduction to the course

Minerals

  1. Chemical elements form in stars
  2. Atoms bond by sharing electrons
  3. Minerals are classified by their chemistry
  4. Minerals can be identified by their physical properties = atomic structure
  5. Silicates are the most important mineral group
  6. Crystals are determined by mathematical rules called symmetry

Igneous Rocks and Volcanoes

 

Weathering and Erosion

 

Evolution of Landscapes

 

Sedimentary Rocks

 

Evolution, Fossils, Geologic Time

 

Glaciers

What Glaciers Do

  1. Glaciers are flowing streams of ice
  2. Glaciers have a zone of accumulation where snowfall exceeds losses (ablation)
  3. Accumulation can be due to high altitude (mountain glaciers) or cold climate (continental glaciers)
  4. Glaciers have a zone of ablation where losses exceed snowfall
  5. Glaciers are governed by a balance of snowfall, ice flow, and ablation
  6. Glaciers retreat by melting back, not by retracting
  7. Glaciers produce distinctive landforms and small scale features

Ice Ages

  1. The recent period of ice advances since 2.5 million years ago is called the Pleistocene
  2. The best record of Pleistocene ice advances is on the sea floor
  3. There were probably 20+ advances of the ice, of which only the last few are preserved on land.
  4. Over most of the earth's history, the earth has been mostly ice free
  5. Tiny changes in earth's orbit and axis tilt play a role in ice advances by varying the amount of sunlight we receive
  6. The carbonate-silicate cycle governs the balance of carbon dioxide in the atmosphere and in rocks and creates �€œicehouse�€� and �€œgreenhouse�€� periods
  7. We still have no final answer why ice ages occur

How Ice Age Glaciers Affected Us

  1. The Pleistocene glaciers profoundly affected world geography and history
  2. The Missouri and Ohio Rivers were created because the glaciers blocked existing rivers
  3. The Great Lakes were excavated by the glaciers
  4. The English Channel was formed because the glaciers blocked existing rivers
  5. The ice affected migration of humans into the Americas

Wind and Wave Erosion

 

Metamorphism and Deformation

  1. Rocks change due to heat, pressure, and fluids
  2. Heat in the earth is original heat plus heat from radioactive decay
  3. Pressure is simply from the weight of overlying rocks. Pressure = Depth
  4. What happens during metamorphism
  5. Different metamorphic conditions result in different rocks and minerals
  6. Metamorphic rocks reveal temperature and pressure conditions in the earth.

Deformation

  1. Structures in the earth have practical implications
  2. Basic terms for earth structures
  3. Small structures provide clues to much larger structures
  4. The earth's crust is floating on the denser mantle beneath
  5. Gentle uplifts and downwarps affect the interiors of continents

Earthquakes and Earth's Interior

  1. Earthquakes generate waves that travel through the earth
  2. Earthquakes occur when rocks slip along faults
  3. Faults are classified by the kinds of movement that occur along them
  4. Earthquakes don't kill people, buildings kill people
  5. Magnitude and Intensity
  6. Seismic waves are used to map the earth's interior
  7. Predicting earthquakes is not yet possible

Continental Drift and Plate Tectonics

  1. How we know plate tectonics happens
  2. Most earthquakes and volcanoes occur along plate boundaries
  3. New ocean crust is created along mid-ocean ridges
  4. Old ocean crust is recycled at subduction zones
  5. Subduction zones are where mountain-building (orogeny) occurs
  6. Small pieces of crust (terranes) are important in building up continents
  7. Hot spots are long lived stationary magma sources

Resources from the Earth

Geology of other Worlds

Return to Professor Dutch's Home Page

Created 16 June 2009, Last Update 15 January 2020