The Argument for Continental DriftThe Argument for Continental Drift
Alfred L. WegenerAlfred L. Wegener Geologist Alfred Wegener noticed Geologist Alfred Wegener noticed
similar rocks & fossil remains were similar rocks & fossil remains were found on continents which seemed found on continents which seemed to fit togetherto fit together
He called this “super” continent He called this “super” continent called Pangaea called Pangaea
In 1912 Wegener In 1912 Wegener published the published the first version & first version & died defending died defending his theoryhis theory
Geologist Alfred Wegener noticed Geologist Alfred Wegener noticed similar rocks & fossil remains were similar rocks & fossil remains were found on continents which seemed found on continents which seemed to fit togetherto fit together
He called this “super” continent He called this “super” continent called Pangaea called Pangaea
In 1912 Wegener In 1912 Wegener published the published the first version & first version & died defending died defending his theoryhis theory
PANGAEA PANGAEAthe large landmass that included all of Earth’s
present day continentsthe large landmass that included all of Earth’s
present day continents
Permian225 million years ago
Permian225 million years ago
Triassic200 million years ago
Triassic200 million years ago
Jurassic135 million years ago
Jurassic135 million years ago
Cretaceous65 million years ago
Cretaceous65 million years ago
Present DayPresent Day
CONTINENTAL DRIFTCONTINENTAL DRIFT
http://www.tectonics.caltech.edu/movies/outreac
h/sumatra/pangaea.mov
Support for Continental DriftSupport for Continental Drift
1. SHAPE OF THE CONTINENTSContinents fit together like puzzle pieces
1. SHAPE OF THE CONTINENTSContinents fit together like puzzle pieces
Mesosaurus was incapable of swimming across a large ocean.
2. FOSSIL EVIDENCE2. FOSSIL EVIDENCE
SAME FOSSILS: DIFFERENT CONTINENTS
Support for Continental DriftSupport for Continental Drift
3. ROCK EVIDENCE – Mountain ranges3. ROCK EVIDENCE – Mountain ranges
Support for Continental DriftSupport for Continental Drift
SAME ROCK: DIFFERENT RANGE Existing mountain ranges separated by vast oceans contain rocks of identical mineral content.
A prime example are the Appalachian Mountains in the eastern U.S and the Caledonian Mountains in the British Isles.
SAME ROCK: DIFFERENT RANGE Existing mountain ranges separated by vast oceans contain rocks of identical mineral content.
A prime example are the Appalachian Mountains in the eastern U.S and the Caledonian Mountains in the British Isles.
SAME SCARS: DIFFERENT CONTINENTSSAME SCARS: DIFFERENT CONTINENTS
Support for Continental DriftSupport for Continental Drift
4. GLACIAL SCARS4. GLACIAL SCARS
5. LOCATION OF COAL DEPOSITS 5. LOCATION OF COAL DEPOSITS
Coal deposits have been found in temperate and polar regions; however, coal is formed in tropical regions.
Coal deposits have been found in temperate and polar regions; however, coal is formed in tropical regions.
Support for Continental DriftSupport for Continental Drift
CONTINENTAL DRIFT IN DOUBTCONTINENTAL DRIFT IN DOUBTWhy didn’t people believe in continental drift?
People couldn’t imagine how the earth could be millions of years old
People couldn’t imagine a force great enough to move the continents
Why didn’t people believe in continental drift?
People couldn’t imagine how the earth could be millions of years old
People couldn’t imagine a force great enough to move the continents
THETRUTH!
THETRUTH!
North America moves about 1 to 2 centimeters away from Europe every year.
North America moves about 1 to 2 centimeters away from Europe every year.
The Earth’s CrustThe Earth’s Crust
Plate: large pieces of the crust that moves
Plate: large pieces of the crust that moves
The Earth’s crust consists of a number of Plates
The Earth’s crust consists of a number of Plates
Plate Tectonics: The interaction of the crustal plates
Plate Tectonics: The interaction of the crustal plates
ConvergentConvergent
Over riding plate goes over the top
Over riding plate goes over the top
Subducting plate slides underneath
Subducting plate slides underneath
Boundry is the area where the two meet
Boundry is the area where the two meet
Convergent = Coming together Convergent = Coming together
Moving PlatesMoving Plates
Divergent = Moving apart Divergent = Moving apart
Moving PlatesMoving Plates
Transform = Moving laterally Transform = Moving laterally