what two types of crust make up the surface of the earth
Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet or natural satellite, which is chemically distinct from the underlying mantle. The crusts of Earth, Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantles. The Earth's crust is composed of distinctly different continental crust and oceanic crust, which have different chemical compositions and physical properties, and which were formed by different geological processes.