About a hypothesis of formation of the Moon according to A.A. Marakushev. O.V. AVCHENKO, A.V. ASEEVA

Abstract

About a hypothesis of formation of the Moon according to A.A. Marakushev. O.V. AVCHENKO, A.V. ASEEVA (Far East Geological Institute, FEB RAS, Vladivostok).

Results of synthesis of literary data concerning isotope geochemistry of lunar rocks show that isotope composition of oxygen, silicon, chrome, tungsten, titanium and zirconium is not so different from composition of terrestrial rocks that testifies to a uniform source of a genesis of the Earth and the Moon. At the same time the isotope composition of flying components of lunar rocks – chlorine, rubidium, zinc, gallium, potassium, iron is considerably fractioned and enriched with heavy isotopes, compared with isotope composition of terrestrial rocks. It is explained by manifestation of kinetic isotope effect which takes place when dissipation of flying components happens from the surface of magma in open space. Thus, crystallization of lunar rocks took place in conditions other than terrestrial. The origin of the Moon is considered in the light of A.A. Marakushev’s hypothesis according to which the Moon separated from proto-Earth whose mass at the expense of a fluid cover created the necessary moment of an impulse. This event is dated by the age about 50 million years since the beginning of formation of the Solar system and took place along with the beginning of pulse separation of proto-Earth heavy nucleus. Future Moon was formed of rather light silicate material, but with capture of the proto-Earth mantle. It is emphasized that other two most reasonable hypotheses of origin of the Moon – via a giant impact or evaporations cannot explain all features of isotope composition of lunar rocks and origin of Galilean satellites of the Jupiter.