what is the the earth upper mantle made of
The uppermost mantle is connected to the crust and forms the asthenosphere, which composes Earth's tectonic plates. The bulk of the mantle is composed of extremely hot rock under enormous pressure. The mantle may be very close to the melting point of the rock which composes it, or even partially melted.Mantle rock is higher in magnesium and iron than the crust.Rocks in the upper mantle are composed of the minerals olvine, garnet, spinel and pyroxene. With increasing depth, some of these minerals become unstable and are replaced by mineral polymorphs which have the same chemical composition, but different structures.he mantle may be very close to the melting point of the rock which composes it, or even partially melted. Mantle rock is higher in magnesium and iron than the crust. Rocks in the upper mantle are composed of the minerals olvine, garnet, spinel and pyroxene.