Double BSR in Nankai Trough as a tool to study stability of subsurface gas hydrates

南开海槽的双 BSR 作为研究地下天然气水合物稳定性的工具

• 批准号: 12480147
• 负责人: MATSUMOTO Ryo
• 金额: $ 9.34万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12480147/
• 关键词: Nankai Trough; DBSR; ODPLeg204; Cascadia margin; Kuroshima Knoll; Methane seep; Carbonate nodules; Dolomite; ガスハイドレート; 塩分濃度; 酸素同位体組成; 永久凍士; 塩素濃度; 水素同位体組成; ヨウ素

1. Double BSR was reported from the eastern Nankai Trough in 1995. This research has conducted extensive analysis of seismic profiles obtained by JNOC methane hydrate project, and has revealed that DBSRs are widely distributed in the eastern Nankai Trough. This implies that this unique phenomena were probably caused by regional geologic events.2. Submersible dives to the area where DBSR were recognized were not so productive during the cruise. However, carbonate nodules which were incidentally collected from the northern extension of DBSR area by fisherman showed very interesting data, indicating that the area experienced strong methane expultion, and strong methane flux were caused by gas hydrate dissociation.3. Variable types of carbonate nodules were collected from active methane seep sites on the Kuroshima Knoll off Ishigaki Island. Geochemical signatures of the nodules indicate that chimney like nodules are all composed of dolomite, carbonate carbon is strongly depleted in 13C and enriched in 18O, suggesting influence of methane and hydrate-derived waters.4. Large number of water and sediment samples have been collected from the Cascadia margin off Vancouver, Canada, where DBSRs are identified below active methane seep sites. Geochemical analysis has revealed that top sediments are characterized by positive anomaly of chloride, seep gases contain significant amount of thermogenic methane, and sulfate concentration of pore waters decrease with depth depending of methane flux.

1. 1995年在南海海槽东部发现了双BSR。本研究对JNOC甲烷水合物项目获得的地震剖面进行了广泛的分析，发现DBSR在南开海槽东部广泛分布。这意味着这种独特的现象可能是由区域地质事件引起的。在巡航期间，潜水到DBSR被确认的区域并不是那么富有成效。然而，渔民在DBSR地区北方延伸区偶然采集的碳酸盐结核显示了非常有趣的数据，表明该地区经历了强烈的甲烷排出，强烈的甲烷通量是由天然气水合物分解引起的.从石垣岛附近黑岛穹丘的活跃甲烷渗漏点收集了不同类型的碳酸盐结核。结核的地球化学特征表明，烟囱状结核均由白云岩组成，碳酸盐碳强烈亏损13C而富集18O，表明受甲烷和水合物水的影响.从加拿大温哥华外的卡斯卡迪亚边缘采集了大量的水和沉积物样品，在那里，在活跃的甲烷渗漏点下面识别出DBSR。地球化学分析表明，表层沉积物具有氯离子正异常的特征，渗漏气体中含有大量的热成因甲烷，孔隙沃茨中硫酸盐浓度随甲烷通量的增加而降低。

项目成果

Lu, H., Matsumoto, R., Tsuji, Y., Oda, H.: "Anion plays a more important role than cation in affecting gas hydrate stability in electrolyte solution? -a recognition from experimental results"Fluid Phase Equilibria. V.178. 227-234 (2001)

Lu, H., Matsumoto, R., Tsuji, Y., Oda, H.：“阴离子在影响电解质溶液中天然气水合物稳定性方面比阳离子发挥更重要的作用？——实验结果的认可”流体相平衡。

松本 良: "メタンハイドレートの分布、産状、メタン量"海洋生物136. 23巻5号. 439-445 (2001)

Ryo Matsumoto：“甲烷水合物的分布、发生和数量”海洋生物学 136. Vol. 23，No. 5. 439-445 (2001)

Watanabe,Y.Lu Hailong,: "Minor and trace element geochemistry of the Blake Ridge sediments at Site 997"Sci.Results,,College Station,ODP. Vol.164. 151-164 (2000)

渡边，Y.陆海龙，“997号站点布莱克岭沉积物的微量和微量元素地球化学”Sci.Results，大学站，ODP。

Lu, Hailong, Matsumoto, R: "Preliminary experimental results of the stable P-T conditions of methane hydrate in a nannofossil-rich claystone column"Geochemical Journal, 36. 21-30 (2002)

陆海龙，松本R：“富含超微化石粘土岩柱中甲烷水合物稳定P-T条件的初步实验结果”地球化学杂志，36。21-30（2002）

増田昌敬: "メタンハイドレート層からのガス生産技術"海洋と生物. 23巻5号. 478-482 (2001)

Masataka Masuda：“甲烷水合物层的天然气生产技术”，海洋与生物科学，第 23 卷，第 5 期，478-482（2001 年）。