Theories of Plate Tectonics and Continental Drift Start cutting and gluing!!! https://www.youtube.com/watch?v=Saxh_mGHt1I

1880 – 1930 German meteorologist and geophysicist who developed the first theory of continental drift. He used 3 pieces of scientific evidence to develop his theory in the early 1900s.

Gigantic “supercontinent” that existed 200 million years ago. Means “All Earth”

1910 Theory that states that parts of the Earth’s crust drift atop a liquid core. (convection currents in the mantle) Theory was rejected at first because Wegener couldn’t explain how the continents moved (thought that they floated on water).

Continents fit together like puzzle pieces. The same fossils were found where pieces fit together. Similar landforms are found on each continent.

1906 – 1969 U.S. Navy officer and geologist 1960 – Hess made his single most important contribution – Seafloor Spreading Theory.

Earth’s crust moved laterally away from long, volcanically active oceanic ridges. 3 forms of evidence: Molten material Drilling samples Magnetic Stripes

1908 – 1993 Canadian Army Colonel, geophysicist, and geologist 1965 – contributed the theory of Plate Tectonics. Conceived of the transform fault, a major plate boundary where 2 plates move past each other horizontally.

The idea that the rigid outer layers of the Earth, the lithosphere, are broken up into numerous pieces or “plates” that move independently over the weaker asthenosphere. Predicated (based) on the work of Wegener and Hess.