The Earth's crust
The Earth’s crust is its lightest, most buoyant rock layer. Continental crust covers 41percent of the Earth’s surface, though a quarter of that area is under the oceans. The continental crust is 20 to 80 kilometers thick. Its rocks hold four billion years of Earth history. The remainder of the Earth is covered by oceanic crust. This type of crust is young — none older than 170 million years — and is only about 8 kilometers thick.
Topic: Earth Science
Subtopic: Earth Structure
Keywords: Continental crust, Earth (Planet)--Crust, Earth (Planet)--History, Geology
The interior of the Earth is hot, and its temperature increases with depth.
Continental crust is significantly thicker than oceanic crust.
Much of the evidence from the oldest period of the Earth’s history, the Hadean era (3.8 to 4.5 billion years ago), has been destroyed by erosion, burial, and modifications of the rocks as they were heated and compressed at depth.