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Theory of Theory of Continental DriftContinental Drift
James Hutton 1785 James Hutton 1785 UniformitarianismUniformitarianism
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UniformitarianismUniformitarianism
The present is the key to the pastThe present is the key to the past The geological forces and processes The geological forces and processes
of today are the same as those from of today are the same as those from the past.the past.
These forces are very slow and These forces are very slow and methodical.methodical.
Alfred Wegener 1915 Alfred Wegener 1915 Continental DriftContinental Drift
Recurring patterns on Recurring patterns on continentscontinents
Evidence for continental Evidence for continental driftdrift
Matching Coastlines(jigsaw puzzle)
Evidence for continental Evidence for continental driftdrift
Matchingfolded mountainRanges(Atlas, Appalachians, and Scandinavian Highlands)
Evidence for continental Evidence for continental driftdrift
Matching glacierdeposits
Evidence for continental Evidence for continental driftdrift
MatchingFossils(Lystrosaurus)
Evidence for continental Evidence for continental driftdrift
Matching coastlinesMatching coastlines Matching folded mountainsMatching folded mountains Matching glacier depositsMatching glacier deposits Matching fossilsMatching fossils
PangaeaPangaea
A Greek word meaning “All-lands” A Greek word meaning “All-lands” Split apart approximately 200 MYBPSplit apart approximately 200 MYBP
1915 maps by Wegener 1915 maps by Wegener of Pangaeaof Pangaea
Continental driftContinental drift
Theory that continents drift on the Theory that continents drift on the surface of the Earthsurface of the Earth
No mechanism proposedNo mechanism proposed No one believed this was possibleNo one believed this was possible Do you think continents can float ?Do you think continents can float ?
Glomar ChallengerGlomar Challenger
1960’s this ship took core samples of 1960’s this ship took core samples of ocean floor rocks as it crossed the ocean floor rocks as it crossed the Atlantic OceanAtlantic Ocean
A map was produced from this data A map was produced from this data showing the rock types and agesshowing the rock types and ages
From this map a new theory was From this map a new theory was developed to explain Wegener’s developed to explain Wegener’s evidenceevidence
Ocean floor rock agesOcean floor rock ages
Get older symmetrically away from Get older symmetrically away from ridges, the oldest rocks have to be ridges, the oldest rocks have to be 200,000,000 years old200,000,000 years old
Theory: sea floor splits apart and Theory: sea floor splits apart and rocks move away from each otherrocks move away from each other
Process: Seafloor spreadingProcess: Seafloor spreading Seafloor spreading provides clues to Seafloor spreading provides clues to
mechanism driving continental driftmechanism driving continental drift
Topography of ocean Topography of ocean floorfloor
Does sea floor spreading explain Does sea floor spreading explain everything ?everything ?
If the Atlantic Ocean is spreading, If the Atlantic Ocean is spreading, doesn’t that mean some place is doesn’t that mean some place is being squeezed togetherbeing squeezed together
Recurring patterns in Recurring patterns in oceansoceans
Plate TectonicsPlate Tectonics
Combining Wegener’s evidence, Combining Wegener’s evidence, Glomar Challenger’s data, and the Glomar Challenger’s data, and the following world map the present following world map the present theory of Plate Tectonics came into theory of Plate Tectonics came into beingbeing
Earthquake and Volcano Distribution