Metallic Iron in the Planets Interior: Generalization of Thermomagnetic and Microprobe Results

Abstract

The thermomagnetic and microprobe data for metallic iron in terrestrial rocks (xenoliths from upper mantle hyperbasites, Siberian trapps, and oceanic basalts) compared to the data for metallic iron from sediments, lunar basalts and meteorites are shown. It was found that the metallic iron particles contained in all groups terrestrial and extraterrestrial rocks are similar in composition, shape, and grain size. This similarity suggests the similar sources of these particles origin. This means that the terrestrial conditions were close to the conditions that existed at the source planets of the meteorites, e.g., the bodies from the asteroid belt were subsequently disintegrating, and crushing into cosmic interplanetary dust, which fell into the terrestrial sediments. This similarity originates from the homogeneity of the gas-dust cloud at the early stage of the Solar System and obviously other star-planetary systems and subsequent gravitational differentiation in the process of all planet formation. The predominance of extraterrestrial metallic iron in sediments is accounted for by the fact that the interplanetary dust is mainly contributed by the upper mantle material of the source planets of cosmic dust.