New data on relationship between earth's crust and upper mantle

Abstract

New data on velocities of elastic waves in rocks and minerals under pressures, anisotropism of elastic properties of monocrysts, volcanism, deep seismic profiles, isotopic composition of strontium and distribution-abundance of Sr87 in ancient and in young rocks, and others, tend to show that the M discontinuity is but an expression of the state of compaction of the rocks, devoid of any petrographic or geochemical connotations, that the sialitic shell of the Earth, with its heterogeneities, extends to depths exceeding 100 km (i.e. deeper than the M), and that the two types of the crust, oceanic and continental, created by geophysicists, are actually one and the same type. Tentatively drawn analogies between the terrestrial and the lunar crust, on the assumption of a lunar origin of tektites, and the.crust of Mars, with regard to densities and planetary size relationships, are used as illustrations of the re-evaluated ratios between the crust and the upper mantle of the earth. — IGR Staff.