Finding of Refractory Inclusions in the North Kolchim Meteorite (H3)

Abstract

For the first time among Russian meteorites, refractory forsterite-rich inclusions are determined in the North Kolchim meteorite (H3). Forsterite-rich inclusions are found mainly in carbonaceous chondrites; they are extremely rare in ordinary chondrites. These inclusions are considered by most researchers as one of the earliest formations in the Solar System. The inclusions of the North Kolchim meteorite are composed of high-magnesia forsterite (FeO 0.4–2%), which contains higher CaO (0.5–1%) and Al₂O₃ contents (up to 0.4%) and is depleted in MnO. In some places, forsterite is found in intergrowths with high-magnesia enstatite (FeO of 0.5–2.5%) also containing CaO impurities of up to 0.5%, Al₂O₃ of up to 1.5%, and MnO below the detection limits. A characteristic feature of forsterite-rich inclusions is that, unlike chondrules, they are mostly represented by acute-angled fragments, and that is probably due to their relatively frequent collisions.