This is a continuation of an ongoing project, and the overall goals of the research are two: 1) to characterize the processes that control the subduction of sediments; and 2) to characterize the time scales of magma differentiation in island-arcs. This will be accomplished by determining the concentrations of 10Be, 9Be, 226Ra, 230Th, K, Ba, and Rb in about 50 island-arc volcanic rocks and their phenocryst separates. 10Be will be measured by accelerator mass spectrometry at the University of Pennsylvania. 9Be will be determined by electron-capture detection gas chromatography at the Massachusetts Institute of Technology, 226Ra and 230Th activities will be determined ba gamma- and alpha-spectrometry at the University of Chicago, K, Ba, and Rb will be determined by atomic absorption/emission flame photometry at the University of Chicago. ***//
