CONTINENTAL DRIFT. Alfred L. Wegener Geologist and meteorologist Alfred Wegener noticed similar...
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Transcript of CONTINENTAL DRIFT. Alfred L. Wegener Geologist and meteorologist Alfred Wegener noticed similar...
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