Collaborative Research: U-Series, Be, Sr, Nd and Pb Isotopic and Trace Element Constraints on Melting and Mass Transfer Processes in Arcs, Philippine Arc System

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Collaborative Research: U-Series, Be, Sr, Nd and Pb Isotopic and Trace Element Constraints on Melting and Mass Transfer Processes in Arcs, Philippine Arc SystemEAR-0208095; EAR-0207429; EAR-0207830PIs: Asmerom; Morris; MukasaNet material cycling between the mantle and continental crust occurs primarily in arcs. Many processes related to melting and mass transfer in arcs, such as the relative contributions of melting and devolatilization in transferring elements from sediment and altered oceanic crust or the relative roles of dynamic, decompression or flux melting of the mantle wedge, however, remain enigmatic. This Collaborative proposal will focus on Luzon, located in the tectonically simpler part of the Philippines arc, to compare two different arc settings in close proximity that may have had dissimilar geochemical histories. The presumed difference in sediment contribution makes the proposed site an ideal setting for studying mass transfer processes and their possible effects on mantle melting. Combined U-series and Be isotopic data, in conjunction with long-lived radiogenic and trace element data will be used to study these rocks. The following goals are set forth: 1) to characterize lavas, using major, trace and Nd, Sr and Pb isotopic data, from four volcanic centers, two from each arc in order to delineate attributes of each subduction zone; 2) to determine the nature and composition of the sediment component and the mechanism by which it is added to the mantle; 3) to investigate the role of dynamic melting in arcs; and 4) to investigate the behavior of U-series nuclides during magma differentiation.