南海共轭大陆边缘发育演变时空特征的非均性与目标钻探井位

Spatiotemporal heterogeneity of the conjugate continental margin evolution in the South China Sea and future ocean drilling wells

  • 摘要: 南海是西太平洋最大的边缘海之一,位于欧亚板块、菲律宾海板块和印度-澳大利亚板块的转换交接部位,也是太平洋构造域与特提斯洋构造域全球两大构造体系的交汇点,蕴含着丰富的前沿地球科学问题。聚焦南海区域4+1次大洋钻探航次(ODP184、IODP349、IODP367、IODP368及IODP368X),系统总结了中生代以来南海深海盆从陆缘张裂、海底扩张,到气候环境和沉积演变取得的重要进展。基于南海共轭大陆边缘在形成演化过程中时空分布不均一性,凝练了陆缘伸展减薄过程、洋陆过渡带张破裂过程、岩浆活动动力学机制和莫霍面优选等4个科学主题。以往的大洋钻探多数限于南海大陆边缘北部中段,对整个南海的控制约束作用有限。针对上述科学问题,对南海相关数据进行了详细解释分析,在南海东北次海盆、西南次海盆和西北次海盆提出9个科学钻探站位,以期全面、完整和具体地揭示南海生命史。在今后工作中坚持深浅结合、难易结合的原则,开展实施南海大洋钻探,不仅具有支撑未来天然气水合物钻采船在南海海域钻探的现实需求,而且对刻画南海完整生命史具有重要科学意义。

     

    Abstract: The South China Sea is one of the largest marginal seas in the Western Pacific. It is located at the transition and junction of the Eurasian Plate, the Philippine Sea Plate and the Indo-Australian Plate and contains a wealth of cutting-edge geoscience issues.Based on the previous ocean drilling expeditions (ODP184, IODP349, IODP367, IODP368, and IODP368X) in the South China Sea, the important progresses were summarized systematically since the Mesozoic, including the basin rifting, seafloor spreading, climate change, and sedimentary evolution respectively. Focusing on the Spatiotemporal heterogeneity during the evolutionary process of the conjugate continental margin, four scientific themes are proposed, such as the extension and thinning process of the continental margin, the rift process of the ocean-continent transition zone, the dynamic mechanism of magmatic activity. Most of the previous oceanic drilling expeditions are constrained to the middle part of the northern continental margin of the South China Sea, and have limited control on the entire South China Sea. In order to solve the above scientific problems, 9 drilling sites are proposed in the northeast sub-basin, southwest sub-basin and northwest sub-basin of the South China Sea through the detailed interpretation of the relevant data. Thus, a comprehensive, complete and specific evolution process of the South China Sea will be revealled. Adhering to the principle of combining the depth and the shallow, and the combination of difficulty and ease, the proposed sites will be carried out for the implementation of the South China Sea ocean drilling in the future, which not only has the practical needs to support the future drilling and mining of natural gas hydrate in the South China Sea, but also has important scientific significance for depicting the complete life history of the South China Sea.

     

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