CONTINENTAL DRIFT SEAFLOOR SPREADING THEORY OF PLATE TECTONICS Plate Tectonics.
Plate Tectonics
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Transcript of Plate Tectonics
Plate TectonicsEnvironmental Science
Plate TectonicsThe Earth Inside Out
Bathymetry and Seafloor MappingThe Theory of Continental Drift
Lab continental drift
Seafloor SpreadingLab seafloor spreading
Plate TectonicsLab plate tectonics
Earth’s Internal LayersHow 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
elementsInner 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 coreLower mantle is solid, upper mantle is “plasticy”
Lithosphere and Asthenosphere
Lithosphere and AsthenosphereLithosphere = Crust and upper part of upper
mantleAsthenosphere = lower part of upper mantleLithosphere “floats” on asthenosphere
Rock CycleWhat are the three types of rock? How does the
rock cycle account for their formation?
Isostatic EquilibriumHow 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
IsostasyThe 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 ReboundIsostatic 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 DriftWhat 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 TheoryPangea: big supercontinentPanthalassa – Ocean surrounding PangeaWegner theorized that because the less dense
continents floated on the more dense matle, Pangea broke apart into separate pieces.
Theory of Continental Drift
The EvidencePieces 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
geologistTo many gaps between continentsHe disappeared on an expedition in 1930 in
GreenlandLater 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!