南海东北部陆坡天然气水合物钻探区生物地层与沉积速率  

Calcareous Nannofossils and Foraminifera Biostratigraphy on the Northeastern Slope of the South China Sea and Variation in Sedimentation Rates

作　　者：陈芳[1] 庄畅[1] 周洋[1] 苏新[2] 段虓 刘广虎[1] 吴聪[1] 荆夏[1] 

机构地区：[1]广州海洋地质调查局,国土资源部海底矿产资源重点实验室,广东广州510075 [2]中国地质大学海洋学院,北京100083

出　　处：《地球科学（中国地质大学学报）》2016年第3期416-424,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金面上项目(No.41372012);国家专项项目课题(No.GZH2011003050602)

摘　　要：2013年我国首次在南海东北部东沙陆坡实施天然气水合物钻探,并获取块状等可视天然气水合物样品.为了解钻区地层、天然气水合物产出带（the zone of gas hydrate occurrence）或天然气水合物储层的地层时代和沉积速率特征,对其中5个站位（GMGS05、GMGS07、GMGS08、GMGS09和GMGS16）的岩心沉积物进行钙质超微化石、有孔虫生物地层学和沉积速率变化的研究.钻孔取心最大深度为213.55m.共识别出第四纪中更新世以来3个钙质超微化石事件和2个有孔虫事件,确定了钻探区所钻达最老地层为中更新统;天然气水合物产出带的地层时代为中更新世-全新世约0.44Ma以来.钻区0.12Ma以来的沉积速率介于36.9~73.3cm/ka之间,平均值高达54.2cm/ka,0.44Ma以来平均沉积速率为47.4cm/ka,表明东沙海域天然气水合物钻探区位于一高沉积速率堆积体上,高沉积速率更有利于天然气水合物的成藏,该结论与前人研究结果一致.Middle Pleistocene to Holocene calcareous nannofossils and foraminifera biostratigraphy in 5 sites （GMGS05, GMGSOT,GMGSO8,GMGS09 and GMGS16） from the Dongsha gas hydrate drilling area of the northeastern South China Sea have been studied. A total of 3 nannofossils events and 2 foraminifera events from middle Pleistocene to Holocene were recog- nized. The oldest sediments recovered are in an age of middle Pleistocene, younger than 0.50 Ma, the age assigned for gas hy- drate occurrence zone is middle Pleistocene to Holocene in sites GMGS05, GMGS07, GMGS08 and GMGS16. Sedimentation rates varied from 36.9 cm/ka to 73.3 cm/ka, and reaching the highest average value 54. 2 cm/ka since 0. 12 Ma in the Dongsha gas hydrate drilling area. The mean sedimentation rate has been 47.4 cm/ka since 0. 44 Ma. The results suggested that the gas hydrate drilling area is located at sedimentary body with high sedimentation rate, which is advantageous to gas hydrate formation. This conclusion is consistent with the previous research.

关 键 词：生物地层 沉积速率 中更新世 天然气水合物钻区 南海东北部陆坡 

分 类 号：P744.4[天文地球—海洋科学]