Chondrite diversity revealed by chromium, calcium and magnesium isotopes

Chondrites are undifferentiated meteorites that can provide information on the compositions of materials in early solar System, including building blocks terrestrial planets. While most chondrites belong to well-defined groups based their mineralogy and chemical composition, a minor fraction have unusual characteristics classified as ungrouped chondrites. These reflect diversity chondritic system; however, they not well studied grouped origins poorly understood. In this study, we present high-precision mass-independent Cr, Ca Mg isotope data for 17 The ?54Cr ?48Ca (? expresses parts per ten thousand deviation) also important constraints assessing relationships known chondrite groups, radiogenic ratios (?26Mg*) be used track system history. We first Kakangari (KC) chondrite, an enstatite four enstatite-rich meteorites. values KC ?0.44 ± 0.04 ?1.30 0.25, respectively, value SAH 97096 (EH3) is ?0.19 0.22 overlaps with those Earth-Moon ordinary All carbonaceous chondrite-like (CC) show positive values, all non-carbonaceous (NC) KCs (also NC trend) zero or negative values. This observation confirms CC-NC dichotomy primitive materials. LEW 87232 shows highest 55Mn/52Cr ratio ?53Cr amongst There trend between among mostly reflects mixing multiple components. Previously it has been reported there bulk 26Al-26Mg correlation line interpreted being due CAIs (high 27Al/24Mg ?26Mg* values) other silicate material (e.g., chondrules matrix). By providing additional data, no chondrites, ruling out two-endmember (i.e., silicates) model.