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
International Association for Engineering Geology and the Environment large projects and in the assessment and remediation of environmental issues, an update of the first statutes of the association was deemed necessary. The second statutes were approved by the general assembly in Kyoto (Japan) in 1992. A new definition of engineering geology was given, which reflected the experience collected during the previous 25 years and read as follows: "“Engineering geology is a science devoted to the investigation, study and solution of engineering and environmental problems which may arise as the result of the interaction between geology and the works and activities of man as well as to the prediction