Intellectual Merit: This research is a four-institution collaboration that supports geochemical studies of volcanic rocks collected by dredging volcanic the western Aleutian seafloor during a cruise carried out in July-August 2005. Preliminary results show that the rocks contain a large proportion of primitive lavas that include not only basalts, but also andesites and dacites with unusual trace element compositions. Goals of the project are to analyze 100 of these samples and use the data to model the petrological and geochemical processes leading to their genesis and evolution and placing these results in the context of subduction zone magmatic processes. Analytical efforts will focus on whole-rock geochemistry including major and trace elements, determine Pb, Sr, Nd and Hf isotopic ratios on a subset of the 100 samples, carry out electron microprobe studies of phenocrysts and glass inclusions in some of the freshest glass-containing lavas, and use the ion probe to determine trace element compositions of pyroxene phenocrysts and glass inclusions hosted by olivine and pyroxene. A small, no-cost pilot study of volatile and light elements in glass inclusions will be carried out by a collaborator at the Carnegie Institution of Washington.
Broader Impacts: This research involved collaboration between four institutions and will support a PhD student and undergraduates at a university in South Carolina, which is an EPSCoR state. The project also engages a new investigator in ocean science. Geochemical analyses will support shared use analytical facilities thereby helping sustain the infrastructure for science. Data will be archived and made available to the public on well know geochemical databases, including GeoRock and PetDB.
