Evidence for Plate Tectonics The Old Stuff and The New Stuff
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Evidence for Plate Tectonics
The Old Stuff and
The New Stuff
Wegener’s EvidenceThe Old Stuff
It was MY idea!
Puzzle Fit Continents
Mesosaurus Fossils
Mountain Range Evidence
Problem with Wegener’s Stuff
Oh . . . Phooey!
New Evidence for Plate Tectonics
The New Stuff
Seafloor Spreading
The seafloor contracts and sinks.
Crust spreads along an ocean ridge and magma fills the gap that is created.
Hot magma, which is less dense than the surrounding material, is forced toward the crust.
New seafloor moves away from the ridge, cools and becomes more dense than the material beneath it.
New seafloor forms as the magma hardens.
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Mantle ConvectionConvergent Divergent
Downward
Upward Arm
Slab Pull
Ridge Push
Earthquake Data
Hot Spots To get a chain of volcanoes,
the plates MUST be moving!
I knew it!
Ocean Drilling
Location Age of Rocks
Ridge Crests Youngest
Continental Margins 180 mya
Continental Crust 4.0 bya
Do you believe in Plate Tectonics?
Where are we going from here?
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