Determination of trace element partition coefficients from experiments at high pressure using the proton microprobe

The partitioning of up to 7 indicator trace elements (Rb, Sr, Ba, Y, Zr, Nb and Ta) between silicate minerals (amphibole, clinopyroxene, mica) and silicate (basanite or tholeiitic andesite) or carbonatitic magmas at high pressure and temperature has been determined using the HIAF proton microprobe. These determinations for the silicate magmas are at natural or slightly enriched elemental levels, except for Nb and Ta which were significantly enriched. The results provide essential data for the modelling of low-degree melting processes in the earth's mantle, and also for the modelling of geochemical modification (trace element enrichment) of localized regions in the earth's mantle, where this may be caused by highly alkaline (nephelinitic) or carbonatitic melts. 8 refs., 1 tab