Question

Continents float high because they are __________.

Answer 1

The continents do not float on a sea of molten rock. The continental and oceanic crusts sit on a thick layer of solid rock known as the mantle. While there is a layer of liquid rock in the earth known as the outer core, this layer is about 3000 km below earth's surface and is separated from the surface by the thick solid mantle. The tectonic plates do not slowly drift over time because they are floating on a layer of liquid rock. They drift because they are sitting on a layer of solid rock (the upper mantle or "asthenosphere") that is weak and ductile enough that it can flow very slowly under heat convection, somewhat like a liquid.