Predoctoral fellow Tatjana Rehfeldt, a Ph.D. student at the Johannes-Gutenberg Universität in Mainz, Germany, arrived in May to begin work with Rick Carlson. While at DTM Rehfeldt will carry out Re/Os isotope analyses of ultramafic cumulate xenoliths (dunites, wehrlites, and pyroxenites) from kimberlites of the Kaapvaal Craton (southern Africa). The analyses will be done on whole-rock samples as well as olivine and spinel separates with the aim of addressing whether these xenoliths were derived from Archaean lower oceanic crust that had been subducted into the Archaean upper mantle.