南海天然气水合物钻孔自生黄铁矿硫同位素特征  

Sulfur isotopes of authigenic pyrites in the sediments of gas-hydrate drilling sites,Shenhu area,South China Sea

作　　者：陆红锋[1,2] 刘坚[1,2] 吴庐山[1,2] 陈芳[1,2] 廖志良[1,2] 

机构地区：[1]国土资源部海底矿产资源重点实验室 [2]广州海洋地质调查局,广东广州510760

出　　处：《地学前缘》2015年第2期200-206,共7页Earth Science Frontiers

基　　金：国家自然科学基金项目(41372012);中国地质调查局水合物专项下属课题(GZH201100305-06)

摘　　要：南海神狐海域天然气水合物钻探岩心含有大量自生黄铁矿,主要为长条状、短柱状。黄铁矿主要出现在沉积物浅部和含水合物层,含量主要为20%~90%。SH5C岩心(不含水合物)的黄铁矿硫同位素δ34SV-CDT变化范围为-40.488‰^-19.538‰,SH7B岩心(含水合物)的黄铁矿δ34SV-CDT为-38.922‰~37.660‰。尤其在水合物层的黄铁矿硫同位素组成偏重,δ34SV-CDT在22‰~27‰,这是水合物盖层形成的封闭体系和AOM持续发生共同作用的结果,可能是水合物层中独特的硫同位素特征。Large amounts of authigenic pyrites occurred in the sediments of gas-hydrate drilling sites, Shenhu area, South China Sea. The morphologies of pyrites are as the form of long rod and short column, which mainly exist in the shallow sediments and gas hydrate-bearing sediments. Pyrite content ranges from 20% to 90% and reaches to the maximum at the gas hydrate-hearing layer, δ34Sv-CDT of pyrites of core SH5C （no gas hydrate） varies between -40. 488‰ and -19. 538‰, which indicates an open system to seawater sulfate. δ34Sv-CDT of pyrites of core SHTB （gas hydrate-bearing） ranges from -38. 922‰ to 37. 660‰, especially focuses on the range between 22‰ and 27‰. This sulfur isotopic composition of pyrites resulted from anaerobic oxidation of methane （AOM） in gas hydrate-bearing sediment where a close system was formed by the capping of the gas hydrate deposit.

关 键 词：南海 天然气水合物 自生黄铁矿 硫同位素 

分 类 号：P578.292[天文地球—矿物学] P597.2[天文地球—地质学]