(Table T1) Geochemistry of anhydrite separates from hydrothermal veins and vug fills of ODP Leg 193 sites, PACMANUS field

Sr and S isotope data as well as trace element data for anhydrite samples from Sites 1188 and 1189 in the PACMANUS hydrothermal area are presented here. 87Sr/86Sr ratios range from 0.7050 to 0.7086, suggesting that the anhydrites precipitated from fluids that were variably influenced by entrained seawater (0%–89%). d34S values range between 18.1 per mil and 22.5 per mil, indicating the main source of sulfate is seawater that may be affected to small extents by sulfide oxidation or magmatic sulfate input (d34S < 21 per mil) and minor sulfate reduction (d34S > 21 per mil). Rare earth element (REE) concentrations are highly variable, particularly at Site 1188. Chondrite-normalized REE pattern shapes comprise light REE enriched, light REE depleted, mid-REE enriched, and variable positive and negative Eu anomalies. Significant correlations between trace element and isotopic compositions are lacking. Anhydrite from Site 1188, a site of diffuse venting, has systematically lower d34S and higher Sr contents and somewhat lower average 87Sr/86Sr than anhydrite from Site 1189. This is possibly a consequence of the different fluid flow regime with diffuse flow at Site 1188 and focused flow at Site 1189.