南海西南次海盆柱状沉积物酸类化合物的地球化学特征  

GEOCHEMICAL CHARACTERISTICS OF FATTY ACIDS IN THE SOUTHWEST SUB-BASIN OF THE SOUTH CHINA SEA

作　　者：王先庆 陈升 许兰芳 彭登 WANG Xianqing;CHEN Sheng;XU Lanfang;PENG Deng(Guangzhou Marine Gcological Survey,China Gcological Survey,Guangzhou 510075,China;Sanya South China Sea Institute of Geology,Guangzhou Marine Geological Survey,Sanya 572024,China;School of Marine Sciences,Sun Yat-sen University,Guangzhou 510006.China;Guangzhou Institute of Energy Conversion,CAS,Guangzhou 510640,China)

机构地区：[1]中国地质调查局广州海洋地质调查局,广州510075 [2]广州海洋地质调查局三亚南海地质研究所,三亚572024 [3]中山大学海洋科学学院,广州500060 [4]中国科学院广州能源研究所,广州510640

出　　处：《海洋地质前沿》2020年第7期17-24,共8页Marine Geology Frontiers

基　　金：国家自然科学基金(91428205,41776056);广东省基础与应用基础研究基金(2020A1515011172)。

摘　　要：南海西南次海盆是南海海盆中的一个重要构造单元,了解其沉积物的地球化学信息对于认识南海沉积环境至关重要。采用色谱质谱(GC-MS)方法对南海西南次海盆B3C和C7两个站位沉积柱中的酸类化合物进行研究,结果表明:(1)南海西南次海盆B3C和C7站位柱状沉积物中的正构脂肪酸呈偶奇优势分布,普遍以n-C16和n-C18为主;沉积物主要来源于浮游生物、藻类、细菌等,并有陆源高等植物的贡献。(2)B3C和B7沉积柱中酸类化合物来源主要以海源为主,总正构脂肪酸含量以及陆源优势正构脂肪酸(n-C24、n-C26、n-C28)、海源优势正构脂肪酸(n-C12、n-C14、n-C16)含量在垂向上分布较为稳定,变化波动小,表明该地区的大部分时期沉积环境较为稳定。(3)总脂肪酸(TFA)和TFA/TOC均表明该区域有机物积累普遍较低,且该处沉积区域处于非透光区和非热液区。The Southwest Sub-Basin is an important tectonic unit in the South China Sea.Geochemical information preserved in sediments is essential to the understanding of the sedimentary environment of the basin.In this paper,fatty acids in two sediment cores from the Southwest Sub-Basin were analyzed with GC-MS.The results suggest that:(1)The n-fatty acids in the sediment columns B3C and B7 show an even-odd distribution pattern dominated by n-C16 and n-C18,sourced from vascular plants,soil materials,plankton,algae,and bacteria,contributed by both the terrestrial plants and marine diatoms.(2)The acid compounds in the core sediments of B3C and B7 are dominated by marine sources.The content of total n-fatty acid and terrestrial dominant n-fatty acids(n-C24、n-C26、n-C28),marine-source dominated n-fatty acids(n-C12、n-C14、n-C16)vary slightly in the vertical direction,indicating that the sedimentary environment was rather stable for most of the time.(3)Total fatty acids(TFA)and TFA/TOC ratio indicate that the accumulation rate of organic matter in this area is generally low,and the depositional area belongs to a non-transparent zone without hydrothermal activities.

关 键 词：南海西南次海盆 柱状沉积物 生物标志化合物 脂肪酸 

分 类 号：P736.21[天文地球—海洋地质]