ORIGIN OF KIMBERLITES: EVIDENCE FROM ISOTOPIC-GEOCHEMICAL DATA

Abstract

Most hypotheses about the origin of kimberlites explain the specific composition of the rocks (high content of incompatible elements, mainly, LREE) by the low degree of partial melting of the lithospheric mantle during formation of the magmatic kimberlite chambers. Various hypotheses differ mainly in the composition of the mantle protolith and source depth. The asthenosphere is typically considered as the main source. However, its relation to magma chamber has not been discussed. In analyzing isotopic-geochemical data on a representative collection of kimberlites and related rocks of the Siberian Craton, we focused our attention on the correlation between isotope-geochemical and chemical compositions, which makes it possible to refine the model of kimberlite formation.