Module 7: Plate Tectonics and Earth's Structure

The pressure and heat within Earth’s interior are the natural forces that power Earth’s dynamic systems. Earth’s layers are layered by density, with a hot solid core of iron and nickel at the center. The upper layer of the mantle is molten and plastic, allowing the solid rigid crust to move on top of it. The heat from Earth’s core radiates outward, causing hot magma to rise and cooler rocks to sink and melt. This transfer of energy has enough power to move the Earth’s tectonic plates as if they were on a slow conveyor belt. Convection has caused the Earth’s tectonic plates to move and collide for billions of years, pushing the continents together and then pulling them apart over and over.

Just looking at a map of the Earth shows that the continents easily fit together like a giant jigsaw puzzle. Tectonic movement creates the landforms of the Earth and causes volcanoes and earthquakes as plates move about. These processes will not continue indefinitely. Billions of years from now when the heat from Earth’s interior cools and convection stops driving the movement of the plates, Earth will be a very different place to live.