CONTINENTAL DRIFT

Alfred L. Wegener  Geologist and meteorologist Alfred Wegener noticed similar rocks & fossil remains were found on continents which seemed to fit together  He hypothesized there was once a super continent he named Pangaea  In 1912 Wegener published the first version & died defending his theory  Geologist and meteorologist Alfred Wegener noticed similar rocks & fossil remains were found on continents which seemed to fit together  He hypothesized there was once a super continent he named Pangaea  In 1912 Wegener published the first version & died defending his theory

Support 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 Drift 1. SHAPE OF THE CONTINENTS Continents fit together like puzzle pieces 1. SHAPE OF THE CONTINENTS Continents fit together like puzzle pieces

Mesosaurus was incapable of swimming across a large ocean. 2. FOSSIL EVIDENCE SAME FOSSILS: DIFFERENT CONTINENTS Support for Continental Drift

3. ROCK EVIDENCE – Mountain ranges Support 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 CONTINENTS Support for Continental Drift 4. GLACIAL SCARS

5. LOCATION OF COAL DEPOSITS Coal deposits have been found in temperate and polar regions; however, coal is only formed in tropical climates. Support for Continental Drift

PANGAEA the large landmass that included all of Earth’s present day continents

CONTINENTAL DRIFT IN DOUBT 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 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 1.Flat 2.Unchanging 3.Older than continental crust 1.Flat 2.Unchanging 3.Older than continental crust  Not until technological advancements from WWII were these misconceptions shown to be false

Mapping 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.

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

Magnetic 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 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.

But, I’m pretty sure this is how it really happened…  TzzGPfVx32M TzzGPfVx32M  TzzGPfVx32M TzzGPfVx32M