Isotope compositions of C and O of magmatic calcites from the Udachnaya-East pipe kimberlite, Yakutia

摘要

It has been demonstrated for the first time that the isotopic compositions of carbon (delta C-13) in magmatic calcites from the Udachnaya-East pipe kimberlite groundmass varies from-2.5 to-1.0aEuro degrees (V-PDB), while those of oxygen (delta O-18) range from 15.0 to 18.2aEuro degrees (V-SMOW). The obtained results imply that during the terminal late magmatic and postmagmatic stages of the kimberlite pipe formation, the carbonates in the kimberlite groundmass became successively heavier isotopically, which indicates the hybrid nature of the carbonate component of the kimberlite: it was formed with contributions from mantle and sedimentary marine sources.