9314505 Stolper In this project the PIs will use a new C sphere technique to segregate very low% melts at the solidus of three peridotites, one of which is somewhat "pristine", and the other two are more "depleleted". Their experiments will be carried out at 5 35 kbar pressure. Ther results will be used to develop models for polybaric fractional fusion processes beneath mid oceanic ridges. ***