Crust (geology) the crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. The crust of the Earth is of two distinctive types: Because both continental and oceanic crust are less dense than the mantle below, both types of crust "float" on the mantle. This is isostasy, and it's also one of the reasons continental crust is higher than oceanic: continental is less dense and so "floats" higher. As a result, water pools in above the oceanic crust, forming the oceans. The temperature of the crust increases with
International Association for Engineering Geology and the Environment International Association for Engineering Geology and the Environment The International Association for Engineering Geology and the Environment (), formerly International Association for Engineering Geology, also known as IAEG (), is an international scientific society which was founded in 1964. It is affiliated with the International Union of Geological Sciences (IUGS) and has 3,798 members and 59 national groups all over the world. The association aims to promote and encourage the advancement of engineering geology through technological activities and research. At the same time it strives to improve teaching and training in engineering geology, and to collect, evaluate and disseminate the