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
Chaotian (geology) the Mundrabilla iron meteorite of Western Australia using the argon method determined an age of 4,570 ± 60 million years ago. The proposed collision with Theia, leading to the formation of the Moon, is estimated to have occurred 4.527 billion years ago. Outgassing and differentiation of the earth in an iron-rich core and mantle may have been completed 4.45 billion years ago. Chaotian (geology) In the geologic record the Chaotian eon or era is unofficially proposed to denote the time preceding the solidification of the Earth's crust and the formation of Earth's moon, it is the earliest era within the