Transcript
Evidence for Plate Evidence for Plate TectonicsTectonics
The Old Stuff andThe Old Stuff and
The New StuffThe New Stuff
Wegener’s EvidenceWegener’s Evidence
The Old StuffThe Old Stuff
Puzzle Fit ContinentsPuzzle Fit Continents
Mesosaurus FossilsMesosaurus Fossils
Mountain Range EvidenceMountain Range Evidence
Problem with Wegener’s StuffProblem with Wegener’s Stuff
New Evidence for New Evidence for Plate TectonicsPlate Tectonics
The New StuffThe New Stuff
Earthquake DataEarthquake Data
Hot SpotsHot Spots
Ocean DrillingOcean Drilling
Location Age of Rocks
Ridge Crests Youngest
Continental Margins 180 mya
Continental Crust 4.0 bya
Mantle ConvectionMantle ConvectionConvergent Divergent
Downward
Upward Arm
Slab Pull
Ridge Push
Seafloor SpreadingSeafloor 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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Do you believe in Plate Do you believe in Plate Tectonics?Tectonics?
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