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| 南海台西南区碳酸盐岩矿物学和稳定同位素组成特征——天然气水合物存在的主要证据之一 | |
| 引用本文： | 陆红锋,刘坚,陈芳,廖志良,孙晓明,苏新.南海台西南区碳酸盐岩矿物学和稳定同位素组成特征——天然气水合物存在的主要证据之一[J].地学前缘,2005,12(3):268-276. |
| 作者姓名： | 陆红锋 刘坚 陈芳 廖志良 孙晓明 苏新 |
| 作者单位： | 1. 广州海洋地质调查局,广东,广州,510760;中山大学,地球科学系,广东,广州,510275 2. 广州海洋地质调查局,广东,广州,510760 3. 中山大学,地球科学系,广东,广州,510275 4. 中国地质大学(北京),北京,100083 |
| 基金项目： | 中国地质调查局资助项目 |
| 摘 要： | 南海台西南区是中国南海中天然气水合物赋存的最有利场所。研究表明,该区的碳酸盐岩主要以结壳、烟囱的形式出现,结壳的裂隙或孔洞中常常充填有淡黄-白色的文石晶体。碳酸盐岩中自生碳酸盐矿物主要为文石、高镁方解石,少量白云石、铁白云石和菱铁矿。扫描电子显微镜(SEM)分析表明,文石主要呈针状、长柱状、放射束状,高镁方解石呈颗粒状。碳酸盐岩的碳同位素δ13C值主要在-56·878‰~-32·829‰PDB之间,大多数小于-40‰PDB,显示了生物甲烷成因碳源的特征;氧同位素δ18O值在2·1875‰~5·045‰PDB之间,主要在4‰PDB以上,这种较重的氧同位素比值表明,天然气水合物分解产生的富18O水体可能是碳酸盐岩沉淀的流体源。矿物学和碳氧稳定同位素研究表明,南海台西南区的碳酸盐岩为细菌性甲烷成因碳酸盐岩,可能与天然气水合物有关,显示了该区水合物存在的可能性很大。 |
| 关 键 词： | 台西南区 天然气水合物 碳酸盐岩 碳氧稳定同位素 |
| 文章编号： | 1005-2321（2005）03-0268-09 |
| 收稿时间： | 2005-06-20 |
| 修稿时间： | 2005-07-20 |
Mineralogy and stable isotopic composition of authigenic carbonates in bottom sediments in the offshore area of southwest Taiwan, South China Sea:Evidence for gas hydrates occurrence |
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| LU Hong-feng,LIU Jian,CHEN Fang,LIAO Zhi-liang,SUN Xiao-ming,SU Xin.Mineralogy and stable isotopic composition of authigenic carbonates in bottom sediments in the offshore area of southwest Taiwan, South China Sea:Evidence for gas hydrates occurrence[J].Earth Science Frontiers,2005,12(3):268-276. | |
| Authors: | LU Hong-feng LIU Jian CHEN Fang LIAO Zhi-liang SUN Xiao-ming SU Xin |
| Institution: | 1. Guang zhou Marine Geological Survey. Guang zhou 510760.China;2. Department of Earth Sciences. Sun Yat sen University, Guangzhou 510275,China;3. China University of Geosciences , Beijing 100083,China |
| Abstract: | The offshore area of southwest Taiwan, South China Sea, is the best gas-hydrate prospect area. Authigenic carbonates in the area occur in the form of crusts and chimneys. X-ray studies show that carbonate minerals are aragonite, high-Mg calcite, and lesser dolomite, ankerite and siderite. Aragonite is acicular, elongate and fills voids of the carbonates. High-Mg calcite is granular. The δ~(13)C values of carbonates range from -56.878‰PDB to -32.829‰PDB, most less than -40‰PDB, suggesting a microbial methane-associated carbon reservoir. The δ~(18)O values of carbonates range from 2.1875‰PDB to 5.045‰PDB, giving a heavy value of O isotope ratios and indicating a ~(18)O-enriched water resource. Studies of the mineralogy and oxygen and carbon stable isotopic compositions provide clues that the carbonates from the offshore area of southwest Taiwan were probably precipitated from the cold seeps,which originated from gas hydrate dissociation.KG)] |
| Keywords: | southwest Taiwan gas hydrates authigenic carbonates isotopic compositions |
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