article_snippet: Earth's main layers are the thin crust four to 50 miles (six to 80km)
article_snippet: deep, a mantle extending 1,800 miles (2,900km) deep and the iron core.
article_snippet: The crust and some of the upper mantle form tectonic or lithospheric plates 60 to 90 miles (97 to 145km) thick that are like the top side of conveyor belts carrying continents and seafloors.
article_snippet: The crust and some of the upper mantle form tectonic or lithospheric plates 60 to 90 miles (97 to 145km) are responsible for the formation of continents, and are still active - as earthquakes and volcanic eruptions show.
article_snippet: Earth's main layers (illustrated) are the thin crust four to 50 miles (six to 80km) deep, a mantle extending 1,800 miles (2,900km) deep and the iron core.
article_snippet: The crust and some of the upper mantle form 60- to 90-mile-thick tectonic or lithospheric plates that are like the top side of conveyor belts .