南海神狐海域含水合物层底栖有孔虫群落结构与同位素组成  

BENTHIC FORAMINIFERA AND STABLE ISOTOPIC COMPOSITION OF GAS HYDRATE-BEARING SEDIMENTS FROM SHENHU AREA IN THE NORTHERN SOUTH CHINA SEA

作　　者：陈芳[1] 周洋[1] 苏新[2] 陆红锋[1] 刘广虎[1] 庄畅[1] 

机构地区：[1]广州海洋地质调查局,广州510760 [2]中国地质大学(北京),北京100083

出　　处：《海洋地质与第四纪地质》2010年第2期1-8,共8页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(40742007;40730844);中国地质调查局"天然气水合物资源评价及勘探开发战略研究"基金项目(GZH200200203-02-01)

摘　　要：为评价水合物甲烷对底栖有孔虫群落结构和同位素的影响,对南海北部神狐海域获取天然气水合物的钻孔BY3岩心,进行底栖有孔虫群落结构和稳定同位素分析,发现含水合物层底栖有孔虫丰度、分异度下降,群落中以内生种占绝对优势,有孔虫破碎率增加;与不含水合物层中的底栖有孔虫相比,含水合物层的底栖有孔虫碳同位素值出现较明显的负偏移。含水合物层中的Uvigerinaspp.、Cibicidesspp.和Oridorsalisspp.的δ13C平均值分别为-1.61‰、-0.79‰和-1.80‰,而在不含水合物层它们的δ13C平均值分别为-0.88‰、-0.27‰和-1.04‰;其中Uvigerinaspp.和Oridorsalisspp.的δ13C最轻值均出现在含水合物层,分别为-1.83‰和-2.29‰。这些说明底栖有孔虫在生长和埋藏过程中可能受到沉积物中甲烷水合物形成和演化的影响。The successful gas hydrate expedition from Shenhu area in the northern South China Sea,provides an opportunity to study the influence of gas hydrate methane on the benthic foraminifera and their stable isotopic composition.In this study,benthic foraminifera and their carbon isotopes in hole BY3 from the Shenhu area were reported.The results show there has no obvious distinction in benthic foraminifera assemblage composition between gas hydrate-bearing sediments and non-gas hydrate-bearing sediments.The carbon stable isotope analyses of species（Uvigerina spp.,Cibicides spp.and Oridorsalis spp.）reveal a distinction in foraminifera between gas hydrate-bearing sediments and non-gas hydrate-bearing sediments.Uvigerina spp.,Cibicides spp.and Oridorsalis spp.collected from gas hydrate-bearing sediments exhibit highly variable and strongly depleted δ13C values,with values as-1.61‰,-0.79‰ and-1.80‰ respectively;and mean values are-0.88‰,-0.27‰ and-1.04‰ respectively from non-gas hydrate-bearing sediments.The extremely negative δ13C values of Uvigerina spp.and Oridorsalis spp.are-1.83‰ and-2.29‰ respectively,which occurred in gas hydrate-bearing sediments.The studies imply that the high carbon isotopic excursion were affected by gas hydrate methane.

关 键 词：底栖有孔虫 群落结构 碳同位素 含水合物层 南海 

分 类 号：P736.22[天文地球—海洋地质]