Crustal Movement

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Crustal Movement
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Layers of The Earth

• Core Center of the earth
• Contains Iron and Nickel
• Two Levels
• Inner Core Solid
• Yes there is tremendous heat but it is out
  weighed by the enormous pressure which pushes the
  particles of Iron and Nickel so close together
  that they remain solid.
• Outer Core Liquid
• Here heat out weighs the pressure and the Iron
  and Nickel are molten

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Mantle

• Middle layer of the Earth
• Comprised mostly of silicon, oxygen, iron, and
  magnesium.

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Crust

• Solid and rocky outer layer of the earth
• Think of the crust like an apple peel very thin
  outer layer.
• Types
• Oceanic Crust beneath the ocean
• Comprised of silicon, oxygen, iron, and magnesium
• Continental Crust beneath the continents
• Comprised mostly of silicon, oxygen, aluminum,
  calcium, sodium, and potassium.

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Crust

• Levels
• Lithosphere
• Solid topmost part of the Earth
• Asthenosphere
• Often considered to be the upper edge of the
  mantle
• Made of molten material
• Property of Plasticity
• Able to flow or move easily

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Activity

• Draw your own version of the Earths Layers

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Plate Tectonics

• Continental Drift Theory
• Alfred Wegener
• 1912

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Plate Tectonics

• Continental Drift
• The Theory
• All of the continents were once joined in one
  large land mass, Pangaea, that began breaking up
  and drifting apart millions of years ago
• Wegeners theory was very unpopular and rejected
  by most of the worlds scientists.

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Plate Tectonics

• Continental Drift
• The Evidence
• Identical types of fossils were found in Africa
  and South America
• Many of the Earths rock formations line-up with
  formations on other continents.
• Mountain ranges in African line up with matching
  ones in South America.
• Coal fields with distinct layers in Brazil match
  up with identical fields in Africa

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Plate Tectonics

• Continental Drift
• The Evidence
• Glacial Deposits (Sediments and Rocks left behind
  by glaciers) have been found in South America,
  Africa, India, and Australia.
• The Continental coast lines fit together like the
  pieces of a puzzle.

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Plate Tectonics

• Sea-Floor Spreading
• Harry Hess
• 1960

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Plate Tectonics

• Sea-Floor Spreading
• Discovered a large system of underwater
  mountains.
• Contain a deep crack
• Lava erupts through these cracks pushing the
  ocean floor on either side away.
• The lava hardens and forms new ocean floor.

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Plate Tectonics

• Sea-Floor Spreading
• The evidence
• Samples have shown that the further away from a
  ridge you get the older the rock.
• Magnetic memory of rock material in the ocean
• As magma hardens at ridges half of the rock moves
  in one direction and half moves in the other.
• On each side the magnetic strips match the
  earths magnetic pull.

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Plate Tectonics

• Plate Tectonics
• J. Tuzo Wilson - 1965

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Plate Tectonics

• Plate Tectonics
• Plate
• The moving, irregularly shaped slabs that fit
  together like paving stones to form the surface
  layer of the earth
• Tectonics
• The branch of geology that deals with the
  movements that shape the earths crust

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Plate Tectonics

• Plate Tectonics
• The Theory
• The earths plates are in constant, slow motion,
  driven by convection currents in the mantle.
• Do you know what convection is?
• Seven Major Plates
• Named for the area its surface features.
• For example The Pacific Plate
• Can move up to several centimeters per year.

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Plate Tectonics

• Plate Tectonics
• Convection
• Hot material rises from the core and cool
  material sinks towards the core.
• The cool material then heats and the rises this
  circular cycle causes movement.

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Activity

• Draw your own model of convection currents.

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Plate Tectonics

• Plate Tectonics
• Plate Boundaries
• The points where plates meet.
• 3 Types
• Divergent
• Convergent
• Transform or Strike-Slip

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Plate Tectonics

• Plate Tectonics
• Divergent
• Move apart at mid-ocean ridges.

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Plate Tectonics

• Plate Tectonics
• Boundaries
• Convergent
• Plates come together at trenches One plate
  moving over top of the other.

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Plate Tectonics

• Plate Tectonics
• Boundaries
• Strike-Slip
• Two plates grind together and slip past each
  other horizontally. No new material is created
  and none is destroyed.

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Geological History

• Fossils
• Preserved remains or traces of living things
• Can be used to determine age.

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Geological Time Scale

• Fossils
• Law of Superposition
• In horizontal sedimentary rock layers, the oldest
  rock is on the bottom

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Geological History

• Fossils
• How do you think Paleontologist determine the age
  of fossils?
• Radioactive (Carbon) Dating
• Determines the absolute age of rocks and fossils.
• The rate at which a radioactive element decays is
  a constant.
• Half Life

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Geological History

• Fossils
• Index Fossils
• The remains of plants and animals that existed
  for a relatively short period of time in a wide
  area.
• Tell the relative age of rocks

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Geological History

• Geological Time Scale
• Eras Plaeozoic, Mesozoic, Cenozoic
• Periods Eras are divided into periods.
• Epochs Only in the Cenozoic period because the
  information we have for this era is so much more
  complete.