The 34S-enrichment of arc volcanics relative to Mid-Ocean Basalt and the heterogeneity of mantle values of delta-S34 have been ascribed to contributions from subducted ocenaic crust. Recent work by the Dr. Alt has shown, however, that altered oceanic crust by itself cannot account for these observations. He plans to look for these sources of sulfur and its isotopes in the sediments that are carried into the trench along with igneous basement rocks. He will examine the entire pelagic column and its pore waters at 3 sites from Leg 129 of the Ocean Drilling Program in the western Pacific, define the sulfur budget within the sediment column, and determine the effects of low-temperature metamorphism on sulfur in the uppermost crust.
