Earth, density distribution

Abstract

The Earth’s density structure is now known in sufficient detail to provide a sound basis for discussions of internal composition. High pressure equations of state (Stacey and Davis, 2004), the modern version of finite strain theory, provide reliable extrapolations of density to zero pressure, as well as distinguishing internal heterogeneities caused by temperature variations from compositional and mineralogical differences. Although fine details in the deep interior are not all resolvable, it is evident that the bulk of the Earth does not have very strong lateral heterogeneities, such as are obvious in the crust. Nevertheless, the heterogeneities that are seen are indications of the dynamics of the Earth, making them prime targets for continuing investigation.