Olivine in the Udachnaya-East Kimberlite (Yakutia, Russia): Types, Compositions and Origins 论文

摘要

Olivine is the principal mineral of kimberlite magmas, and is the main contributor to the ultramafic composition of kimberlite rocks. Olivine is partly or completely altered in common kimberlites, and thus unavailable for studies of the origin and evolution of kim-berlite magmas. The masking effects of alteration, common in kimberlites worldwide, are overcome in this study of the exceptionally fresh diamondiferous kimberlites of the Udachnaya-East pipe from the Daldyn^Alakit province, Yakutia, northern Siberia.These serpentine-free kimberlites contain large amounts of olivine (50 vol.%) in a chloride^carbonate groundmass. Olivine is repre-sented by two populations (olivine-I and groundmass olivine-II) differing in morphology, colour and grain size, and trapped mineral and melt inclusions.The large fragmental olivine-I is composition-ally variable in terms of major (Fo85^94) and trace element concen-trations, including H2O content (10^136 ppm). Multiple sources of