MINERALOGY OF SIBERIAN KIMBERLITES

Abstract

Siberian kimberlite minerals are classified according to their occurrence and origin as: 1) Kimberlite minerals - associated directly with kimberlite formation (pyrope, ilmenite, olivine, magnetite, diopside and chrome-diopside, chrome-spinel, perovskite, micas, and enstatite and hypersthene); 2) Xenolithic minerals - either directly related to kimberlites by chemical composition - or in association with this group, but compositionally unrelated to the kimberlites; and, 3) Secondary minerals - formed in secondary alteration of kimberlite principally by serpentinization and carbonitization, and, to a lesser degree, by silicification, chloritization, and pyritization processes. Mineral specimens under investigation were taken at depths not exceeding 3 to 4 meters; thus, they indicate known composition for only the uppermost portion of the kimberlite pipes. Basically Siberian and South African kimberlites are similar: between the two areas, there is little variation in mineral composition;quantitative differ...