To understand this mind-bendingly long history, we need to study rocks and the minerals they are made of ... because it tells us about how the continental crust formed and evolved.

The mantle is made up of magma, or molten rock. And the crust is this layer of solid ... meaning they're found mainly under the ocean, or continental, and mainly found under land.

but also their topography as expansion and contraction of the crust made a mark on the landscape. Some areas of continental crust have maintained long-term stability from the beginning of Earth's ...

The oceanic rocks are usually made from basalt ... This magma then rises up through cracks in the continental crust. As pressure builds up, a volcanic eruption may occur causing composite cone ...