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