SIMS analysis of chlorine in metasomatised upper-mantle rocks

. In spite of the importance of chlorine as a geochemical tracer, Cl data on mantle rocks are nowadays rather scarce mainly due to analytical difficulties. Techniques involving sample dissolution and/or fusion as well as non-destructive bulk techniques are used for Cl determination in silicates but they need rather high amounts of material, which, in most cases, hampers the investigation of this element in single minerals. The SIMS technique represents a powerful tool to address some of the main questions on Cl behaviour in the Earth mantle. We report SIMS data for Cl obtained on upper-mantle peridotites and xenoliths affected by various metasomatic processes. The data were obtained using a SIMS procedure optimised to quantify (ppm) Cl concentration. We investigated the inter- and intra-mineral phase Cl distribution also in relation to other geochemical tracers such as B, Li, REE, Zr and Nb.