This award provides partial support for the operation and maintenance of the ion microprobe facility in the Department of Geology and Geophysics at the Woods Hole Oceanographic Institution. The facility is operated mainly to apply the ion microprobe technique toward the analysis of trace elements and isotopic compositions in geological samples. Access to the capabilities of the instrument is provided by the Woods Hole ion microprobe laboratory for a national community of U.S. researchers in geochemistry.