The first data on the oxygen, carbon, and sulfur isotope composition of the Chelyabinsk meteorite

Abstract

Meteorites are the main source of extraterrestrial material for investigation of regularities of the forma� tion and evolution of solar system matter. The genetic connection of a concrete meteorite to an assumed parental body is based on meteorite classification, which is mostly supported by study of their mineralog� ical and petrographic characteristics, as well as inves� tigation of the bulk chemical composition [1]. In 1973 R. Clayton et al. [2] discovered an anomalous concen� tration of the 17 O isotope in meteorites in comparison with terrestrial rocks. The main differences between terrestrial and extraterrestrial material are controlled by primary isotope heterogeneities in the early solar system. Further investigations of the relative concen� tration of stable isotopes 16 О, 17 О, and 18 O provided the oxygen isotope classification of meteorites and planets and allowed characterization of two important processes of the evolution of the solar system: chemi� cal fractionation and mixing of the components of protoplanetary materials with various isotope compo� sitions [3]. In recent years special attention has been paid to investigation of variations in the stable isotopes in meteorites during genetic identification of meteor� ites and study of the evolution of the matter of the solar system. For this purpose we investigated the oxygen, sulfur, and carbon isotope compositions of a fragment of Chelyabinsk meteorite. Chelyabinsk meteorite rain was registered on Feb� ruary 15, 2013, in Chelyabinsk oblast (Russia). The meteorite was related to the LL group of ordinary chondrites, petrological type 5, shock fraction S4, and weathering degree W0 [4]. An individual fragment of the Chelyabinsk meteorite with a weight of 7 g was used for preparation of bulk samples for the oxygen and carbon isotope analysis. The bulk sample with a total weight of 800 mg was collected from the light part of the meteorite and ground in an agate mortar. None of the chemical methods of treating was applied, since the weathering degree of the Chelyabinsk meteorite was zero (W0). A section with a thickness of 3 mm was cut from the meteorite fragment and polished for local analysis of the sulfur isotope composition.