Mantle (geology) Mantle (geology) The mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles. The Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 kg is 67% the mass of the Earth. It has
Geology of the Alps mountain ranges: the Apennines to the southwest, the Dinarides to the southeast and the Carpathians to the northeast. In the east the Alps are bounded by the Viennese Basin and the Pannonian Basin, where east–west stretching of the crust takes place. The Alps have a complex geology, but the general structure is the same as for other mountain ranges formed by continental collision. The Alps are often divided into Eastern, Central and Western Alps, even though the boundaries between these subdivisions are rather arbitrary. The division between the Eastern and Central Alps is approximately the line between St. Margrethen, Chur