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The Theory of Continental Drift Alfred Wegener, 1911 Melka, 2014-15.

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Presentation on theme: "The Theory of Continental Drift Alfred Wegener, 1911 Melka, 2014-15."— Presentation transcript:

1 The Theory of Continental Drift Alfred Wegener, 1911 Melka, 2014-15

2 Continental Drift… Alfred Wegener proposed that the continents did not stay in one location, but instead slowly drifted in relation to one another. He proposed that all of the continents were once joined into a single super-continent (Pangaea). Pangaea is Greek for “all earth”

3 Continental Drift: The Evidence 1.Shape of the continents suggests that they could fit together like puzzle pieces 2.Same animal fossils are found on opposite shores of the Atlantic Ocean 3.Same sequence of rock layers, including specific kinds of rocks and depths of each rock type, are found on opposite shores of the Atlantic Ocean along coastlines 4.Fossils of tropical plants are found in polar areas, suggesting that the continents now in polar areas were once near the equator 5.Glacial deposits (which only could be created in cold polar areas) are found in tropical areas, suggesting that some continents now in tropical areas were once near the poles

4 Continental Drift: The Evidence Map

5 Continental Drift: Lack of Support There was no explanation as to why or how the continents drifted Hard to believe that something as big as continents could actually move over time

6 Continental Drift: Lack of Support At the time Wegener introduced his theory, the scientific community firmly believed the continents and oceans to be permanent features on the Earth's surface. Not surprisingly, his proposal was not well received, even though it seemed to agree with the scientific information available at the time. A fatal weakness in Wegener's theory was that it could not satisfactorily answer the most fundamental question raised by his critics: What kind of forces could be strong enough to move such large masses of solid rock over such great distances?

7 Continental Drift: Lack of Support Wegener suggested that the continents simply plowed through the ocean floor, but Harold Jeffreys, a noted English geophysicist, argued correctly that it was physically impossible for a large mass of solid rock to plow through the ocean floor without breaking up. FYI: Wegener had a Ph.D. in astronomy and was also very interested in meteorology. He had no formal training in geology, so he didn’t have the credibility of those in the field. He was also fairly young when he introduced his theory of continental drift (his early 30’s).

8 Continental Drift: Lack of Support Undaunted by rejection, Wegener devoted the rest of his life to pursuing additional evidence to defend his theory. He froze to death in 1930 during an expedition crossing the Greenland ice cap, but the controversy he spawned raged on. Born: 1880, Berlin, Germany Died: 1930, Greenland Ice Sheet This is thought to be the last picture taken of Wegener.

9 Continental Drift: Lack of Support After Wegener’s death, new evidence from ocean floor exploration and other studies rekindled interest in his theory, ultimately leading to the development of the Theory of Plate Tectonics. This happened in the late 1960’s. Harry Hess – One of the founding fathers of the Theory of Plate Tectonics.

10 Continental Drift: The Explanation

11 Mid-ocean ridges are areas where sea-floor spreading occur. Sea-floor spreading is the process where new oceanic crust forms at these mid-ocean ridges As the plates move apart from one another, the sea floor spreads apart and magma rises to fill in the gap. This was the explanation as to why the continents moved over time. http://www.brainpop.com/science/earthsystem/platetectonics/

12 Alfred Wegener

13 Future supercontinent? Prediction of future supercontinent, Amasia, named for its fusing the Americas and Asia by closure of the Arctic Ocean and Caribbean Sea. Amasia will be located 90° away from the geographic center of the latest supercontinent Pangaea near present-day Africa.

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15 Pangaea with current geopolitical borders added.

16 Alfred Wegener Alfred Wegener Song by The Amoeba People BrainPop Plate TectonicsBrainPop Plate Tectonics (username: harpool password: longhorns) Earth's Interior & Plate Tectonics Rap Coke + Lava Organic Material + Lava Animation of Pangaea Breakup


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