西太平洋科学大洋钻探的地球动力学成果  

Geodynamic results of scientific ocean drilling in the western Pacific

作　　者：宋晓晓[1] 李春峰[2] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]浙江大学海洋学院海洋地质与资源研究所,浙江舟山316021

出　　处：《热带海洋学报》2016年第1期17-30,共14页Journal of Tropical Oceanography

基　　金：教育部博士点基金项目(20100072110036);国家自然科学基金重点项目(91028007;91428309)~~

摘　　要：西太平洋聚集了地球上大量的边缘海盆和俯冲带,在全球地球动力学研究中占有举足轻重的地位,一直以来都是大洋钻探的重点区域。文章通过归纳过去40年来科学大洋钻探在西太平洋的地球动力学成果,分析当前大洋钻探的现状,进而探讨仍然存在的问题及未来钻探的区域。钻探成果揭示了边缘海盆的演化过程,包括日本海盆的弧后海底扩张成因,菲律宾海的弧后扩张和残留弧的形成模式及南海构造演化过程。深海沉积物的研究及玄武岩的地球化学分析为海盆的扩张成因提供依据,同时为了解海盆扩张过程中的地幔演化过程提供重要信息。大洋钻探成果表明,俯冲倾角大小不仅影响俯冲工厂的动力学机制,而且对俯冲板块耦合性具有控制作用。目前日本南海海槽发震带钻探项目的最大钻探深度为3056米,未来几年有望获得发震带的岩石样本。对于西太平洋的两个重要构造单元-Shatsky海隆和翁通—爪哇海台的成因机制问题,大洋钻探获取的依据仍不能单一地支持某一个假说。在南斐济海盆及赫布里斯海盆发现的大洋红层的形成主要受控于海盆的海底扩张事件。苏拉威西海和南海发现的大洋红层直接发育在大洋玄武岩之上,可能为海盆的扩张起标定作用。虽然过去进行了大量的钻探工作,但因西太平洋边缘海盆具有很大的构造多样性和复杂性,仍然有很多科学问题有待进一步开展研究。With extensive development of marginal basins and subduction zones,the western Pacific is a key area in scientific ocean drilling. This paper intends to show the current status of scientific ocean drilling and discuss potential future breakthroughs,through summarizing scientific ocean drilling results in geodynamics over the past 40 years in the western Pacific. Drilling results documented the evolution of the marginal basins,including the Japan Sea,the Philippine Sea and the South China Sea. Deep sea sediments and geochemical analysis of basalts provided important information for evolution of basins and mantle processes. Ocean drilling results verified that the dip of a subducting slab not only has an effect on dynamic mechanism of the subduction factory but also controls plate coupling at the subduction zone. A record depth of 3056 mbsf had been drilled into the forearc of Nankai Trough subduction zone and retrieval of rock samples from the seismogenic zone is expected in the next few years. Ocean drilling results support more than one hypothesis of formation of the oceanic plateaus in the western Pacific,including the Shatsky Rise and the Ontong Java Plateau. Pelagic brown claystone occurred in the southwestern Pacific marginal basin,and it's formation was controlled by seafloor spreading. In both the South China Sea and the Celebes Sea,pelagic brown claystone lie directly above the basement basalt units. Because of the structural complexity and diversity of the western Pacific,many scientific problems still need to be resolved despite a large number of ocean drilling expeditions.

关 键 词：西太平洋 科学大洋钻探 边缘海盆 俯冲带 洋底高原 大洋玄武岩 深海沉积 

分 类 号：P738.1[天文地球—海洋地质]