Dear Person,

The earth's mantle, which accounts for 67% of earth's mass and 84% of its volume, is a spherical shell with a thickness of 2,900 kilometers. Although the mantle is composed of solid silicate rock, geological time sees the rock behave as a viscous fluid. The mantle is sandwiched between the earth's lithosphere and oceanic crust on its outside, and the outer core on the inside.


geological time