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Plate Tectonics
Environmental Science
Plate Tectonics
 The Earth Inside Out
 Bathymetry and Seafloor Mapping
 The Theory of Continental Drift
 Lab continental drift
 Seafloor Spreading
 Lab seafloor spreading
 Plate Tectonics
 Lab plate tectonics
Earth’s Internal Layers
 How do we classify the Earth’s internal layers?
 How is the lithosphere different from the crust?
Layers of the Earth
Composition, Density and Temp.
 Core: Nickel (Ni), Iron (Fe) and other heavy
elements
 Inner core and outer core same temperature
however massive pressure and density keeps inner
core solid
 Mantle: mostly Silicon (Si) and Oxygen (O)
 Lower density than core
 Lower mantle is solid, upper mantle is “plasticy”
Lithosphere and Asthenosphere
Lithosphere and Asthenosphere
 Lithosphere = Crust and upper part of upper mantle
 Asthenosphere = lower part of upper mantle
 Lithosphere “floats” on asthenosphere
Rock Cycle
 What are the three types of rock? How does the rock
cycle account for their formation?
Isostatic Equilibrium
 How does Archimedes Principle relate to the structure
of the Earth?
 What is isostatic equilibrium?
 What links some earthquakes with isostatic equilibrium?
Where do such earthquakes occur?
Archimedes Principle
Archimedes Principle
Isostatic Equilibrium
Isostasy
 The lithosphere floats
on the asthenosphere
 The various portions of
the Earth’s crust
reach gravitational
equilibrium
 Due to variations in
thickness and density,
some crustal blocks
ride higher than others
Isostatic Rebound
 Isostatic Equilibrium is the balance between the weight
of the lithosphere and the buoyant force of the
asthenosphere
 Isostatic Rebound is when compensation occurs from an
increase or decrease of lithospheric weight…causing
earthquakes along weak areas called - faults
Onto the Festivities!!!
Alfred Wegner and Continental
Drift
 What is Pangea and Panthalassa?
 What is the theory of continental drift?
 What evidence did Wegner use to support his theory?
 Why didn’t scientists support his theory? What further
evidence could have strengthened his theory?
Pangea
Panthalassa
Wegner’s Theory
 Pangea: big supercontinent
 Panthalassa – Ocean surrounding Pangea
 Wegner theorized that because the less dense
continents floated on the more dense matle, Pangea
broke apart into separate pieces.
 Theory of Continental Drift
The Evidence
 Pieces fit together like a puzzle
Fossil Distribution
Accepted Theory? I Think Not!
 Good evidence but no go for public acceptance.
 Possibly because Alfred was a meteorologist not a
geologist
 To many gaps between continents
 He disappeared on an expedition in 1930 in Greenland
 Later on, plate tectonics theory described how the gaps
between the continents were continental shelves
O.k. Let’s Check It Out
Pangea Lab!!!!
Oooooh Yeah Baby!