FORMER DIAMOND-BEARING PHLOGOPITE LHERZOLITE

Abstract

Former diamond-bearing lherzolite consists of primary (olivine, ortho- and clinopyroxene, plagioclase, pargasite, phlogopite, ceylonite, ilmenite and sulfides) and superimposed (amphibole, calcite, phlogopite, apatite, prehnite, diaspore, chlorites and sulfides) mineral associations. Only graphite is associated with the former, while both graphite and diamond are associated with the latter. The chemicals compositions of the lherzolite and its minerals are comparable with those of phlogopite lherzolite and wehrlite xenoliths from kimberlite. The fact that the bronzite lack AlVI, and low-iron diopside lacks alkali probably results from early crystallization of the plagioclase.