Nucleation environment of diamonds from Yakutian kimberlites

Abstract

The micro-inclusions located in the genetic centre of Yakutian diamond monocrystals have been studied using optical (anomalous birefringence, photo luminescence, cathodoluminescence) and microanalytical (electron-microprobe, proton-microprobe, scanning electron microscope) methods. Most diamonds nucleated heterogeneously on mineral seeds, that lowered the energy barrier to nucleation. Nucleation of peridotitic diamonds occurred on a matrix of graphite+iron+wüstite, in an environment dominated by forsteritic olivine and Fe-Ni sulfide. Nucleation of eclogitic diamonds occurred on a matrix of sulfide ± iron in an environment dominated by Fe-sulfide and omphacite (± K-Na-Al-Si-melt). The mineral..