南海天然气水合物的成矿远景
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摘要
通过对南海的中新生代区域构造、中上新世沉积、近—现代地貌及地温条件的分析 ,结合 ODP184航次钻探成果和水合物最新调查资料 ,探讨了南海水合物的成矿条件 ,认为具有良好的成矿地质构造环境 ;通过对南海陆坡深水区现有大量多道地震调查资料的重新判读 ,发现南海地区存在多处水合物的地震标志— BSR,以活动边缘笔架增生楔和非活动边缘西沙—东沙为例 ,重点解剖水合物的地震特征 ,建立其成藏模式 ,总结其成矿规律 ,预测水合物资源远景 ,为今后在该海域寻找水合物矿床、预测水合物资源远景起到抛砖引玉作用
Through the reviewing Miocene regional tectonics,middle Pliocene sediments and recent and modern geomorphic and geothermal conditions in the South China Sea,and together with the latest drilling results and hydrate data from the South China Sea,the authors have made a thorough study on the formation conditions of hydrate in the South China Sea and think that the geologic tectonic environment of the sea is favorable for the formation of hydrate.And after re-interpretation of the available multichannel seismic data from the deep-water areas of the continental slope,double BSR(bottom simulating reflector),slope BSR,platform BSR and basin-edge slope BSR are proven existing in many areas of the sea.Through comprehensive analysis of geophysics,the South China Sea is found to be of BSR,BZ(amplitude blank zone)and VAMP(velocity amplitude anomaly inversion),which are in good coincidence with research results from geologic and geochemical data.An accretion at the active margin and Dongsha-Xisha at the inactive margin are chosen to conduct the studies on hydrate pooling at the margins,probe seismic characteristics of the hydrate,discuss about pooling mechanism,establish the pooling model,summarise mineralization regularities,locate possible occurrence positions of hydrate and predict hydrate prospect. On such basis,the authors give some advance suggestions involving formation environment of hydrate in the South China Sea,dynamic settings and tectonic characteristics,relation between geothermal field features and hydrate formation,hydrate pooling conditions and mechanism,hydrate distributions and resource prospect prediction in the northern continental slope areas,environmental geology and hazard geology of hydrate.These suggestions can play good roles in future explorations for hydrate.
Through the reviewing Miocene regional tectonics,middle Pliocene sediments and recent and modern geomorphic and geothermal conditions in the South China Sea,and together with the latest drilling results and hydrate data from the South China Sea,the authors have made a thorough study on the formation conditions of hydrate in the South China Sea and think that the geologic tectonic environment of the sea is favorable for the formation of hydrate.And after re-interpretation of the available multichannel seismic data from the deep-water areas of the continental slope,double BSR(bottom simulating reflector),slope BSR,platform BSR and basin-edge slope BSR are proven existing in many areas of the sea.Through comprehensive analysis of geophysics,the South China Sea is found to be of BSR,BZ(amplitude blank zone)and VAMP(velocity amplitude anomaly inversion),which are in good coincidence with research results from geologic and geochemical data.An accretion at the active margin and Dongsha-Xisha at the inactive margin are chosen to conduct the studies on hydrate pooling at the margins,probe seismic characteristics of the hydrate,discuss about pooling mechanism,establish the pooling model,summarise mineralization regularities,locate possible occurrence positions of hydrate and predict hydrate prospect. On such basis,the authors give some advance suggestions involving formation environment of hydrate in the South China Sea,dynamic settings and tectonic characteristics,relation between geothermal field features and hydrate formation,hydrate pooling conditions and mechanism,hydrate distributions and resource prospect prediction in the northern continental slope areas,environmental geology and hazard geology of hydrate.These suggestions can play good roles in future explorations for hydrate.
引文
[1] 张光学.海洋国土资源大调查项目建议书——南海北部陆坡甲烷水合物资源调查与评价[R].广州海洋地质调查局(内部资料).1998.
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[3] 张光学.世界海域水合物地震调查研究综述[J].海洋地质,2001,(1).
[4] 张光学,陈邦彦.南海甲烷水合物资源研究与找矿前景[J].海洋地质,2000,(3).
[5] 张光学,陈邦彦,杨胜雄,等.海域天然气水合物地震学研究[A].全国天然气水合物调查动态、勘探方法和成果研讨会文集[C].2001.
[6] 姚伯初.南海的天然气水合物矿藏[J].热带海洋学报,2001,20(2).
[7] 祝有海,吴必豪,卢振权.中国近海天然气水合物找矿前景[J].矿床地质,2001.
[8] LabergJS,AndreassenK,KnutsenS M.Inferred gas hydrateon theBarentsSea shelf—— a model for its formation and avolume estimate[J].Geo-MarineL etters,1998,18:26-33.
[9] LeeN W,HutchinsonD R,AgenaW F ,DillonW P,MillerJJ,SwiftB A.Seismic character of gas hydrates on theSoutheast-ernU .S.continental margin[J].MarineGeophysicalResearch,1994,16:163-184.
[10] AndreassenK.Seismic tudies of a bottom simulating reflec-tion relate to gas hydrate beneath the continental margin oftheBeaufortSea[J].Journal of geophysical research,1995,100(B7):12659-12673.
[11] Hyndm anR D,SpenceG D.A seismic study of methane hy-drate marine bottom simulating reflectors[J].Journal of geo-physical research,1992,97(B5):6683-6698
[12] Hyndm anRoyD,DavisEralE.A mechanism for the forma-tion of methane hydrate and seafloor bottom simulating re-flectors by vertical fluid expulision[J].Journal of geophysi-cal research,1992,97(B5):7025-7041.
[13] GornitzV.Potential distribution of methane hydrates in theworld’s ocean[J].GlobalBiogeochem.Cycles,1994,8:335-347.
[14] http://www-odp.tamu.edu/publications/ODP164航次初步报告[R]
[15] http://www-odp.tamu.edu/publications/ODP184航次最终报告[R]
[2] 张光学,文鹏飞.南海甲烷水合物的地震特征研究[A ].首届广东青年科学家论坛论文集[C].中国科学技术出版社,1999.
[3] 张光学.世界海域水合物地震调查研究综述[J].海洋地质,2001,(1).
[4] 张光学,陈邦彦.南海甲烷水合物资源研究与找矿前景[J].海洋地质,2000,(3).
[5] 张光学,陈邦彦,杨胜雄,等.海域天然气水合物地震学研究[A].全国天然气水合物调查动态、勘探方法和成果研讨会文集[C].2001.
[6] 姚伯初.南海的天然气水合物矿藏[J].热带海洋学报,2001,20(2).
[7] 祝有海,吴必豪,卢振权.中国近海天然气水合物找矿前景[J].矿床地质,2001.
[8] LabergJS,AndreassenK,KnutsenS M.Inferred gas hydrateon theBarentsSea shelf—— a model for its formation and avolume estimate[J].Geo-MarineL etters,1998,18:26-33.
[9] LeeN W,HutchinsonD R,AgenaW F ,DillonW P,MillerJJ,SwiftB A.Seismic character of gas hydrates on theSoutheast-ernU .S.continental margin[J].MarineGeophysicalResearch,1994,16:163-184.
[10] AndreassenK.Seismic tudies of a bottom simulating reflec-tion relate to gas hydrate beneath the continental margin oftheBeaufortSea[J].Journal of geophysical research,1995,100(B7):12659-12673.
[11] Hyndm anR D,SpenceG D.A seismic study of methane hy-drate marine bottom simulating reflectors[J].Journal of geo-physical research,1992,97(B5):6683-6698
[12] Hyndm anRoyD,DavisEralE.A mechanism for the forma-tion of methane hydrate and seafloor bottom simulating re-flectors by vertical fluid expulision[J].Journal of geophysi-cal research,1992,97(B5):7025-7041.
[13] GornitzV.Potential distribution of methane hydrates in theworld’s ocean[J].GlobalBiogeochem.Cycles,1994,8:335-347.
[14] http://www-odp.tamu.edu/publications/ODP164航次初步报告[R]
[15] http://www-odp.tamu.edu/publications/ODP184航次最终报告[R]
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