CONTINENTAL DRIFTCONTINENTAL DRIFT

Alfred L. WegenerAlfred L. Wegener Geologist and meteorologist Alfred Geologist and meteorologist Alfred

Wegener noticed similar rocks & fossil Wegener noticed similar rocks & fossil remains were found on continents remains were found on continents which seemed to fit togetherwhich seemed to fit together

He hypothesized there was once a He hypothesized there was once a super continent he named Pangaea super continent he named Pangaea

In 1912 Wegener In 1912 Wegener published the published the first version & first version & died defending died defending his theoryhis theory

Geologist and meteorologist Alfred Geologist and meteorologist Alfred Wegener noticed similar rocks & fossil Wegener noticed similar rocks & fossil remains were found on continents remains were found on continents which seemed to fit togetherwhich seemed to fit together

He hypothesized there was once a He hypothesized there was once a super continent he named Pangaea super continent he named Pangaea

In 1912 Wegener In 1912 Wegener published the published the first version & first version & died defending died defending his theoryhis theory

Support for Continental DriftSupport for Continental Drift

Wegener was not the first one to notice the fit of the continents.

1500s: Cartographer Abraham Ortelius depicted Africa and South America connected.

Wegener was, however, the first to include other evidence to support his hypothesis.

Wegener was not the first one to notice the fit of the continents.

1500s: Cartographer Abraham Ortelius depicted Africa and South America connected.

Wegener was, however, the first to include other evidence to support his hypothesis.

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 only formed in tropical climates.

Coal deposits have been found in temperate and polar regions; however, coal is only formed in tropical climates.

Support for Continental DriftSupport for Continental Drift

PANGAEA PANGAEAthe large landmass that included all of Earth’s

present day continentsthe large landmass that included all of Earth’s

present day continents

http://www.youtube.com/watch?v=uGcDed4xVD4

CONTINENTAL DRIFT IN DOUBTCONTINENTAL DRIFT IN DOUBTWhy didn’t people accept continental drift?

People couldn’t imagine that the Earth could have looked so different millions of years ago

People didn’t know of a force great enough to move the continents

People couldn’t understand how the continents could move through a solid seafloor

Why didn’t people accept continental drift?

People couldn’t imagine that the Earth could have looked so different millions of years ago

People didn’t know of a force great enough to move the continents

People couldn’t understand how the continents could move through a solid seafloor

Misconceptions of the Seafloor

Misconceptions of the Seafloor

1. Flat2. Unchanging3. Older than continental

crust

1. Flat2. Unchanging3. Older than continental

crust Not until technological

advancements from WWII were these misconceptions shown to be false

Not until technological advancements from WWII were these misconceptions shown to be false

Mapping the Ocean FloorMapping the Ocean Floor

Advancements in sonar allowed scientists to make topographic maps of the ocean floor.

Advancements in sonar allowed scientists to make topographic maps of the ocean floor. What they found were

massive underwater mountain chains complemented by deep canyons.

What they found were massive underwater mountain chains complemented by deep canyons.

Radiometric DatingRadiometric Dating Analysis of ocean rocks showed that the

ocean floor is younger near the ridges and older by the deep-sea trenches.

Analysis of ocean rocks showed that the ocean floor is younger near the ridges and older by the deep-sea trenches.

Magnetic ReversalMagnetic Reversal Our magnetic field changes depending on

the direction of convection currents in the liquid outer core. A magnetometer is able to detect the polarity

of the rock.

Our magnetic field changes depending on the direction of convection currents in the liquid outer core. A magnetometer is able to detect the polarity

of the rock.

Seafloor SpreadingSeafloor Spreading These advancements led to the Seafloor

Spreading theory – explains how new ocean floor is created at ocean ridges and destroyed at deep-sea trenches.

These advancements led to the Seafloor Spreading theory – explains how new ocean floor is created at ocean ridges and destroyed at deep-sea trenches.

But, I’m pretty sure this is how it really happened…But, I’m pretty sure this is how it really happened…

http://www.youtube.com/watch?v=TzzGPfVx32M

http://www.youtube.com/watch?v=TzzGPfVx32M