TY - JOUR
T1 - Data report
T2 - Chemical and isotopic (s, sr) composition of anhydrite from ODP Leg 193, PACMANUS hydrothermal system, manus basin, papua new guinea
AU - Bach, Wolfgang
AU - Roberts, Stephen
AU - Binns, Ray A.
PY - 2007
Y1 - 2007
N2 - 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%). δ34S values range between 18.1‰ and 22.5‰, indicating the main source of sulfate is seawater that may be affected to small extents by sulfide oxidation or magmatic sulfate input (δ34S < 21‰) and minor sulfate reduction (δ34S > 21‰). 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 δ34S 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.
AB - 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%). δ34S values range between 18.1‰ and 22.5‰, indicating the main source of sulfate is seawater that may be affected to small extents by sulfide oxidation or magmatic sulfate input (δ34S < 21‰) and minor sulfate reduction (δ34S > 21‰). 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 δ34S 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.
UR - http://www.scopus.com/inward/record.url?scp=70349192795&partnerID=8YFLogxK
M3 - Article
SN - 0884-5891
VL - 193
JO - Proceedings of the Ocean Drilling Program: Scientific Results
JF - Proceedings of the Ocean Drilling Program: Scientific Results
ER -