| Change of Gas Hydrate Reservoir and Its Effect on the Environment in Xisha Trough since the Last Glacial Maximum |
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| 作者姓名： | 王淑红 颜文 宋海斌 |
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| 作者单位： | Key Laboratory of Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou Center for Gas Hydrate Research Chinese Academy of Sciences Guangzhou 510640 China，Key Laboratory of Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou Center for Gas Hydrate Research Chinese Academy of Sciences Guangzhou 510640 China，Institute of Geology and Geophysics Chinese Academy of Sciences Guangzhou Center for Gas Hydrate Research Chinese Academy of Sciences Guangzhou 510640 China，Guangzhou 510301 China，Guangzhou 510301 China，Beijing 100029 China |
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| 基金项目： | 中国科学院资助项目，国家自然科学基金，the Foundation of Key Laboratory of Marginal Sea Geology |
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| 摘 要： | In this article, Milkov and Sassen’s model is selected to calculate the thickness of the gas hydrate stable zone (GHSZ) and the amount of gas hydrate in the Xisha (西沙) Trough at present and at the last glacial maximum (LGM), respectively, and the effects of the changes in the bottom water temperature and the sea level on these were also discussed. The average thickness of the GHSZ in Xisha Trough is estimated to be 287 m and 299 m based on the relationship between the GHSZ thickness and the water depth established in this study at present and at LGM, respectively. Then, by assuming that the distributed area of gas hydrates is 8 000 km2 and that the gas hydrate saturation is 1.2% of the sediment volume, the amounts of gas hydrate are estimated to be ~2.76×1010 m3 and ~2.87×1010 m3, and the volumes of hydrate-bound gases are ~4.52×1012 m3 and ~4.71×1012 m3 at present and at LGM, re- spectively. The above results show that the thickness of GHSZ decreases with the bottom water tem- perature increase and increases with the sea level increase, wherein the effect of the former is larger than that of the latter, that the average thickness of GHSZ in Xisha Trough had been reduced by ~12 m, and that 1.9×1011 m3 of methane is released from approximately 1.1×109 m3 of gas hydrate since LGM. The released methane should have greatly affected the environment.
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| 关 键 词： | 天然气水合物 储量变化 西沙海槽 海洋环境 上次冰期最盛期 |
| 收稿时间： | 2006-09-26 |
| 修稿时间： | 2006-12-20 |
Change of Gas Hydrate Reservoir and Its Effect on the Environment in Xisha Trough since the Last Glacial Maximum |
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| Wang Shuhong,Yan Wen,Song Haibin.Change of Gas Hydrate Reservoir and Its Effect on the Environment in Xisha Trough since the Last Glacial Maximum[J].Journal of China University of Geosciences,2007,18(1):39-48. |
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| Authors: | Wang Shuhong Yan Wen Song Haibin |
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| Institution: | 1. Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences. Guangzhou 510301, China; Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, China;2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, China |
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| Abstract: | In this article, Milkov and Sassen's model is selected to calculate the thickness of the gas hydrate stable zone (GHSZ) and the amount of gas hydrate in the Xisha (西沙) Trough at present and at the last glacial maximum (LGM), respectively, and the effects of the changes in the bottom water temperature and the sea level on these were also discussed. The average thickness of the GHSZ in Xisha Trough is estimated to be 287 m and 299 m based on the relationship between the GHSZ thickness and the water depth established in this study at present and at LGM, respectively. Then, by assuming that the distributed area of gas hydrates is 8 000 km2 and that the gas hydrate saturation is 1.2% of the sediment volume, the amounts of gas hydrate are estimated to be ～2.76×1010 m3 and ～2.87×1010 m3, and the volumes of hydrate-bound gases are ～4.52×1012 m3 and ～4.71×1012 m3 at present and at LGM, respectively. The above results show that the thickness of GHSZ decreases with the bottom water temperature increase and increases with the sea level increase, wherein the effect of the former is larger than that of the latter, that the average thickness of GHSZ in Xisha Trough had been reduced by ～12m,and that 1.9×1011m3 of methane is released from approximately 1.1×109 m3 of gas hydrate since LGM.The released methane should have greatly affected the environment. |
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| Keywords: | gas Hydrate last glacial maximum (LGM) bottom water temperature sea level Xisha Trough |
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