FIRST DIAMOND FINDS IN PLUTONIC XENOLITHS AT THE EASTERN MARGIN OF THE SIBERIAN CRATON

Abstract

Numerous diamond finds in nonkimberlitic, basaltoid and ultramafic rocks and their serpentinized varieties, commonly with pyrope garnet, as well as in lamproites and mineralogically different types of eclogite, have greatly broadened our ideas about the physical conditions of natural diamond synthesis. Especially informative in this respect are plutonic xenoliths in some types of alkanic basalt and kimberlite breccia, as well as solid inclusions of one or more minerals in diamond crystals. Our diamond finds in plutonic xenoliths of eclogitic rock from compositionally unique kimberlite breccia now add to what is already known about those conditions.