邓义楠, 方允鑫, 张欣, 陈芳, 王海峰, 任江波, 刘晨晖, 关瑶. 南海琼东南海域沉积物的微量元素地球化学特征及其对天然气水合物的指示意义[J]. 海洋地质与第四纪地质, 2017, 37(5): 70-81. DOI: 10.16562/j.cnki.0256-1492.2017.05.007
引用本文: 邓义楠, 方允鑫, 张欣, 陈芳, 王海峰, 任江波, 刘晨晖, 关瑶. 南海琼东南海域沉积物的微量元素地球化学特征及其对天然气水合物的指示意义[J]. 海洋地质与第四纪地质, 2017, 37(5): 70-81. DOI: 10.16562/j.cnki.0256-1492.2017.05.007
DENG Yinan, FANG Yunxin, ZHANG Xin, CHEN Fang, WANG Haifeng, REN Jiangbo, LIU Chenhui, GUAN Yao. TRACE ELEMENT GEOCHEMISTRY OF SEDIMENTS IN QIONGDONGNAN AREA, THE SOUTH CHINA SEA, AND ITS IMPLICATIONS FOR GAS HYDRATES[J]. Marine Geology & Quaternary Geology, 2017, 37(5): 70-81. DOI: 10.16562/j.cnki.0256-1492.2017.05.007
Citation: DENG Yinan, FANG Yunxin, ZHANG Xin, CHEN Fang, WANG Haifeng, REN Jiangbo, LIU Chenhui, GUAN Yao. TRACE ELEMENT GEOCHEMISTRY OF SEDIMENTS IN QIONGDONGNAN AREA, THE SOUTH CHINA SEA, AND ITS IMPLICATIONS FOR GAS HYDRATES[J]. Marine Geology & Quaternary Geology, 2017, 37(5): 70-81. DOI: 10.16562/j.cnki.0256-1492.2017.05.007

南海琼东南海域沉积物的微量元素地球化学特征及其对天然气水合物的指示意义

TRACE ELEMENT GEOCHEMISTRY OF SEDIMENTS IN QIONGDONGNAN AREA, THE SOUTH CHINA SEA, AND ITS IMPLICATIONS FOR GAS HYDRATES

  • 摘要: 天然气水合物已成为重要的战略资源。为探讨天然气水合物富集区的微量元素特征及其指示意义,对琼东南海域沉积物进行系统采样,分析了样品主、微量元素和TOC地球化学特征,并采用氧化还原状态以及氧化还原敏感元素与TOC相关关系的分析方法进行探讨。结果显示:沉积物相较于上地壳更为富集Sr、Pb、Th、U、Zn、Cu和Mo元素,Th/U和V/Sc比值在纵向上呈系统的变化,表层沉积物处于还原的沉积状态,大量富集Mo和U。初步推断研究区部分沉积物可能处于硫化带,使其出现氧化还原敏感元素(Mo和U)的富集,这些特征或由下部天然气水合物分解释放大量的甲烷所导致。表层沉积物孔隙水中出现的硫化带以及Mo和U元素异常,可作为新的地球化学指标以识别下部可能存在的天然气水合物资源。

     

    Abstract: In order to study the geochemical characteristics of trace elements and their implications for gas hydrate, marine sediment samples were systematically collected from the Qiongdongnan area of the South China Sea.The major and trace elements as well as the TOC of the sediments are analyzed, upon which the redox condition, redox-sensitive elements and their TOC correlation are adopted to describe the geochemistry characteristics of sediments.The results indicate that Sr, Pb, Th, U, Zn, Cu and Mo are enriched in the sediments comparing to the average of upper crust.Systematic variations in Th/U, V/Cr values further indicate that the sediments are under a more reducing condition, and as the results, Mo and U are enriched.Some sediment samples have already dropped into the sulfide zone, leading the enrichment of redox-sensitive elements such as Mo and U, owing to the dissociation of gas hydrate and methane fluxes coming from deeper sediments.Therefore, the existence of the sulfide zone and Mo and U enrichment in sediments may have the significance to trace the gas hydrates in deep.

     

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