Isotopic Studies Of Minerals and Their Host Kimberlites from Australia and Southern Africa

Isotopic signatures are used to distinguish Group I, Transition, and Group II kimberlites, and provide information on the origin of melts parental to the final intrusion. Kimberlitic rocks are often weathered and altered, making them potentially unsuitable for whole rock isotopic studies. We therefore have explored the alternative use of the isotopic signatures of resistant minerals in kimberlites including zircon, rutile and perovskite. These minerals also have the advanage of being amenable to rapid dating by the in situ LAICPMS technique (Cooper et al., this conference). The study by Mirnejad et al. (2003) shows altered lamproite whole rock samples, and the mineral phases clinopyroxene, apatite, perovskite, and potassic richerite are in isotopic equilbrium for lamproite. The relationship between the isotopic systems in these minerals and host kimberlites is reported in this study.