冲绳海槽北部柱状沉积物中有机质地球化学特征--对热液活动的指示  

The geochemical characteristics of organic matter in sediment core of the northern of the Okinawa Trough: implication for hydrothermal activity

作　　者：黄鑫[1] 陈法锦[1] 祁雅莉 侯庆华[1] 陈清香[1] 蒲晓强[1] HUANG Xin;CHEN Fa-jin;QI Ya-li;HOU Qing-hua;CHEN Qing-xiang;PU Xiao-qiang(Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction,Guangdong Ocean University,524088,Zhanjiang,China)

机构地区：[1]广东海洋大学,广东省近海海洋变化与灾害预警重点实验室,广东湛江524088

出　　处：《海洋科学》2018年第6期1-11,共11页Marine Sciences

基　　金：中国科学院海洋地质与环境重点实验室开放基金(MGE2015 KG04);广东高校优秀青年创新人才培养计划项目资助(2014KQNCX084);国家海洋局海洋科学重点实验室开放基金(KSLG1503);广东海洋大学博士启动基金(E15169);广东海洋大学创新强校工程项目(GDOU2016050241)。

摘　　要：通过气相色谱-质谱联用仪(GC-MS),分析了冲绳海槽北部柱状沉积物中有机质的分布和组成特征。样品中正烷烃显示出明显的双峰分布,其中高分子正烷烃显示出明显的奇数碳优势;低分子的正烷烃显示出偶数碳优势,其丰度最大值位于C16和C18处。该柱状沉积物中120～140cm层样品(样品S10-7)中沥青、正烷烃以及脂肪酸的含量都要远高于其他层位样品,且该层位样品中正十八烷酸质量比(16.915μg/g)要高于其他层位样品1～2个数量级。S10-7样品中3个成熟度参数也高于其他样品,预示该层位样品受到明显的热蚀变。S10-7样品中有机质的分布和组成情况预示该柱状沉积物样品周围可能存在未被发现的热液区。本研究旨在揭示该柱状沉积物中有机质的来源,同时评估该区热液活动的可能性。本研究的开展可为该区沉积物中有机质来源及热液活动研究提供研究基础和依据。Sediment core samples obtained from the northern of the Okinawa Trough were analyzed for the abundances and distributions of organic compounds by gas chromatography-mass spectrometer.The distributions and compositions of the n-alkanes in the sediment core exhibited an odd to even predominance of high molecular weight n-alkanes and showed a bimodal distribution.The low molecular weight n-alkanes showed an even to odd predominance with maxima at C 16 and C 18 in the sediment core.The concentration of bitumen,alkanes and fatty acid at the layer of 120~140 cm(sample S10-7)in the sediment core were all much higher than those in other layers,and the concentrations of octadecanoic acid in that sample was 16.915μg/g,1~2 orders of magnitude higher than those in other layers.Three maturity parameters in sample S10-7 were higher,suggesting that the sample might be ther-maliy altered.The distributions and compositions of organic matter in sample S10-7 reflect that there may be one or several undetected hydrothermal fields near the sediment core of the northern of Okinawa Trough.The study aims to find out the main source of organic matter in the sediment core,and assess the seafloor hydrothermal activity around the sediment core,which will provide foundation for the research of the source of organic matter and hydrothermal activity in sediment of the northern of the Okinawa Trough.

关 键 词：冲绳海槽 柱状沉积物 热液活动 有机质 

分 类 号：P736.4[天文地球—海洋地质]