神狐海域沉积物孔隙水卤素浓度及碘同位素特征对天然气水合物成藏的示踪研究  

Halogen and iodine isotope of sediment pore water in Shenhu area,northern South China Sea:Insight into the source and genesis of gas hydrate

作　　者：傅飘儿[1,2] 方允鑫 涂公平[1,2] 张路远 王彦美 FU Piaoer;FANG Yunxin;TU Gongping;ZHANG Luyuan;WANG Yanmei(Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou 510075,Guangdong,China;Guangdong Laboratory of Southern Marine Science and Engineering,Guangzhou 511458,Guangdong,China;State Key Laboratory of Quaternary Geology,Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,Shaanxi,China)

机构地区：[1]中国地质调查局广州海洋地质调查局,广东广州510075 [2]南方海洋科学与工程广东省实验室,广东广州511458 [3]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室陕西省加速器质谱技术及应用重点实验室,陕西西安710061

出　　处：《地球化学》2023年第2期191-198,共8页Geochimica

基　　金：国家自然科学基金项目(41606076);广东省科技计划项目(2020B1212060055);南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0209);广东省基础与应用基础研究重大项目(2020B0301030003)联合资助。

摘　　要：对南海北部神狐海域SC-02钻孔沉积物孔隙水开展卤族元素浓度和I同位素研究。根据沉积物孔隙水中Cl^(-)、Br^(-)和I^(-)浓度特征,该钻孔可分为2层:上层沉积物孔隙水中卤族元素浓度随深度增加呈递增趋势;下层沉积物孔隙水卤素浓度则出现大幅波动,可能与该层赋存的水合物在钻取采样时发生分解有关。下层沉积物孔隙水的129I/I年龄为20.77±2.4 Ma,明显老于其赋存地层的年龄,暗示该站位的天然气水合物中CH4可能来自下伏的深部地层。Halogen concentrations and 129I/I ratios were determined in pore water from marine sediments at site SC-02 in the Shenhu area,northern South China Sea.The sediment column can be divided into two sections based on the content of Cl−,Br−,and I−in the pore water of sediments.The halogen concentrations from the upper section are relatively uniform and increase with depth,whereas the contents of Cl−,Br−,and I−in the pore water from the lower section fluctuated widely,which is likely responsible for the hydrate decomposition.The 129I/I ratio corresponds to a minimum age(20.77±2.4 Ma)that is considerably older than that of the present host sediments.The results do not support that gas hydrates were derived from present host sediments.

关 键 词：天然气水合物 孔隙水 卤素 I同位素 南海北部 

分 类 号：P597[天文地球—地球化学] P618.13[天文地球—地质学]