9506730 Plank This project is an experimental study of the behavior of sediments in subduction zones. A major question to be addressed is whether sediments melt or dehydrate beneath arc volcanoes. Another goal is to determine rock/melt and rock/fluid distribution coefficients for important element tracers that can be used in quantitative models. The proposed research will involve high pressure and high temperature laboratory experiments on natural pelitic samples and on metapelites. The chemical compositions of aqueous solutes, melts and residual solid run products will be measured using a new experimental design derived from recent advances in experimental petrology combined with ultrasensitive analytical tools. The data collected should generate further insights into (a) the role of subducted sedimentary material in arc petrogenesis, and (2) the efficiency of crustal recycling throughout Earth history, and (3) the thermal structure of subducting slabs.
