What is Plate Tectonics and How Does it Work?

Alfred Wegener, a German scientist, developed the theory of plate tectonics in the early 1900’s. He published his ideas in a book titled The Origin of Continents and Oceans, in 1915. Wegener noticed that the continents on Earth looked like pieces of a jigsaw puzzle and believed that the continents were once connected.

The History and Acceptance of Plate Tectonics

Wegener thought that the continents looked like they could fit together if they were moved around the planet. For example, Africa and South America have coastlines that look like they could fit together with a little rotation. He also researched and found evidence that similar plant and animal fossils were present along the coastlines of Africa and South America and that mountain ranges on the two continents were the same, giving additional proof to his idea. Wegener called the original landmass Pangaea, which means “all the earth” in Greek, and proposed that it was a huge, supercontinent that once contained all of the Earth’s land. Other scientists, however, did not believe Wegener’s ideas. The theory was not widely accepted by scientists until the 1960s.

What does Plate Tectonics Mean and How Does it Work

Plate tectonics is simply a fancy name for the moving of plates across the surface of the Earth. Wegener believed that the Pangaea landmass broke apart and drifted around the planet to their current locations over millions of years. Over time, other scientists began to believe Wegener’s theory as new research began to back up his ideas. Today, geologists believe that the Earth’s lithosphere, or the outer layer that is composed of the crust and part of the upper mantle, is broken into several huge pieces, or plates. These plates hold the landmasses and oceans. The asthenosphere, is the semi molten layer beneath the lithosphere and, because of convection currents in the layer, allows the plates to move around the Earth at a rate of approximately 5 to 20 centimeters each year. You can learn more about the Earth’s layers here.

Evidence of How Do We Know the Earth’s Plates Moved

The theory of continental drift, actually helps to explain many geological and biological questions. The movement of the plates explains some of the geologic events such as earthquakes and volcano eruptions. As previously mentioned, some identical the plant and animal fossils are present on continents that are now oceans apart. The only way to explain the presence of the same fossils on each continent is that they were once connected. The continental drift theory also explained that mountains formed at different times as the plates moved around the Earth and compressed and folded, lifting the rocks into mountain ranges.


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