Minor elements in unusual olivines from high-pressure peridotites of the kokchetav massif (Northern Kazakhstan)

Abstract

Olivine is one of the most abundant minerals inupper mantle rocks, such as garnet and spinel peridotites of HP/UHP collisional zones and xenoliths inkimberlites and alkali basalts, as well as mineral inclusions in diamonds [1–3]. Having a simple chemicalcomposition, it contains some minor elements ofpetrogenetic importance. In spite of the widespreadabundance of olivine in such rocks, there are only afew studies of its minorelement composition (see thereview in [3]). This is explained by the low concentrations of minor elements in olivine, usually not exceeding 0.1 wt % (except for NiO and MnO), which makesanalytical difficulties for their measurements duringcommon electron microprobe investigations [4].In this paper we discuss the first study of the minorelement composition of olivines from peridotites ofthe wellknown Kokchetav massif in Northern Kazakhstan. These peridotites have an unusual chemicalcomposition characterized by a high concentration ofFeO (13–22 wt %), TiO