Lesson Summary

• Abraham Ortelius first suggested that the Earth might have consisted of a supercontinent.

• Alfred Wegener was the first to present it as a scientific theory in 1912. He called the continent Pangaea.

• Pangaea is theorized to have split up about 200 million years ago.

• Wegener was unable to account for the force necessary to split up a supercontinent. Scientists of that time rejected his theory.

• Harry Hess suggested that the seafloor was spreading as a result of magma bubbling to the surface from the Earth's core.

• The theory of a supercontinent and the evidence of the seafloor spreading combined together is called "plate tectonics."

• Some of the evidence for plate tectonics includes magnetic patterns on the sea floor, fossil records and the relationship between volcanoes and plates.