在发育有全球最大、最复杂的弧—沟—盆体系的西太平洋地区,集中了全球75%左右的边缘海盆(弧后盆地)。根据磁异常条带年龄,这些边缘海盆可粗略分为3个扩张幕。主要根据DS-DP,ODP和IODP计划实施以来所获得的成果,结合其他海洋调查航次研...在发育有全球最大、最复杂的弧—沟—盆体系的西太平洋地区,集中了全球75%左右的边缘海盆(弧后盆地)。根据磁异常条带年龄,这些边缘海盆可粗略分为3个扩张幕。主要根据DS-DP,ODP和IODP计划实施以来所获得的成果,结合其他海洋调查航次研究成果,系统阐述了分属3个扩张幕的西菲律宾海盆(第一扩张幕)、南海—四国海盆(第二扩张幕)和冲绳海槽(第三扩张幕)—马里亚纳海槽内的岩浆活动特点。西菲律宾海盆(扩张时代为65～35 Ma BP)从原先的赤道位置迁移至现今的位置,其内存在如似正常洋中脊玄武岩(NMORB)、洋岛玄武岩(OIB)及弧火山岩等多种岩石类型,其地球动力学背景分别与弧后扩张、地幔柱及火山弧等背景有关,其复杂的构造演化样式需要进一步研究;四国海盆(扩张时代为27～15 Ma BP)是由古伊豆—小笠原—马里亚纳弧(IBM)裂解形成的,其内除发育正常(N)—富集(E)的洋中脊玄武岩(NMORB-EMORB)外,还在扩张停止的同时出现了板内火山作用,形成了中K-超K碱性玄武岩。四国海盆的扩张模式并没有从岩石学和地质年代学角度进行明确制约,板内火山作用的地球动力学背景也不甚清楚。南海(扩张时代为32～15.5 Ma BP)是由来自华南地块的一些微陆块向东南裂离后的海底扩张所形成,并在海底扩张后2～8 Ma出现板内火山作用,截止目前,并没有获取到洋壳基底样品,主要获取到了南海海山似OIB的玄武岩,未来需要从岩石学和地质年代学角度对南海海底扩张动力学和时代以及扩张期后的板内火山作用动力学背景进行进一步制约。马里亚纳海槽(扩张时代为5 Ma BP至今)为一年青的洋内弧后盆地,其北段处于裂解增进阶段,其内出露有似MORB(中南段)及介于似MORB与似岛弧岩石之间过渡类型的玄武岩(增进端);虽然在扩张时代上与马里亚纳海槽相当,但冲绳海槽(扩张时代为4 Ma BP至今)�展开更多
Located at the southern margin of the South China plate, the Youjiang basin is a closely related to the NW- and NE-trending syndepositional faults in respect to the configuration and structure of the basin. The evolut...Located at the southern margin of the South China plate, the Youjiang basin is a closely related to the NW- and NE-trending syndepositional faults in respect to the configuration and structure of the basin. The evolution of the Youjiang basin progressed through two stages. In the Hercynian period, the opening of the Ailaoshan-Honghe ocean basin gave rise to a number of NW-trending rift belts in the Youjiang area. During this period, deep-water sediments were dominant and the basin was possesed of the characteristics of the rift system of passive continental margins. In the early Indosinian after the Dongwu movement, the circum - Pacific tectonism led to a major change in the configuration and structure of the basin. In the meantime, the Ailaoshan ocean basin began to be subducted towards the northeast, thus causing the basin to be split and expand again, and then the basin developed into the stage of the back -arc basin. At the end of the Indosinian period, the basin gradually closed from east to west, thus ending up the history of development of the Youjiang basin. In the various developmental stages, sediments in the basin, also limited by the Dongwu movement, were formed by superposition of sedimentation systems with different features, and a typical two-layered structure, which consisted of starved and compensated sediments, also occurred in the early stage. Likewise, volcanic activity in the basin involved two stages. Basin volcanic rocks of alkali and alkali-calcic series, which were controlled by NW-trending faults, occurred in the early stage, and basic and intermediate-acid volcanic rocks of calc-alkali and calcic series, which were controlled by NW- and NE-trending faults. From the above it follows that the Youjiang basin was formed by the combined action of the Palaeotethys and circum -Pacific tectonism.展开更多
文摘在发育有全球最大、最复杂的弧—沟—盆体系的西太平洋地区,集中了全球75%左右的边缘海盆(弧后盆地)。根据磁异常条带年龄,这些边缘海盆可粗略分为3个扩张幕。主要根据DS-DP,ODP和IODP计划实施以来所获得的成果,结合其他海洋调查航次研究成果,系统阐述了分属3个扩张幕的西菲律宾海盆(第一扩张幕)、南海—四国海盆(第二扩张幕)和冲绳海槽(第三扩张幕)—马里亚纳海槽内的岩浆活动特点。西菲律宾海盆(扩张时代为65～35 Ma BP)从原先的赤道位置迁移至现今的位置,其内存在如似正常洋中脊玄武岩(NMORB)、洋岛玄武岩(OIB)及弧火山岩等多种岩石类型,其地球动力学背景分别与弧后扩张、地幔柱及火山弧等背景有关,其复杂的构造演化样式需要进一步研究;四国海盆(扩张时代为27～15 Ma BP)是由古伊豆—小笠原—马里亚纳弧(IBM)裂解形成的,其内除发育正常(N)—富集(E)的洋中脊玄武岩(NMORB-EMORB)外,还在扩张停止的同时出现了板内火山作用,形成了中K-超K碱性玄武岩。四国海盆的扩张模式并没有从岩石学和地质年代学角度进行明确制约,板内火山作用的地球动力学背景也不甚清楚。南海(扩张时代为32～15.5 Ma BP)是由来自华南地块的一些微陆块向东南裂离后的海底扩张所形成,并在海底扩张后2～8 Ma出现板内火山作用,截止目前,并没有获取到洋壳基底样品,主要获取到了南海海山似OIB的玄武岩,未来需要从岩石学和地质年代学角度对南海海底扩张动力学和时代以及扩张期后的板内火山作用动力学背景进行进一步制约。马里亚纳海槽(扩张时代为5 Ma BP至今)为一年青的洋内弧后盆地,其北段处于裂解增进阶段,其内出露有似MORB(中南段)及介于似MORB与似岛弧岩石之间过渡类型的玄武岩(增进端);虽然在扩张时代上与马里亚纳海槽相当,但冲绳海槽(扩张时代为4 Ma BP至今)�
基金This paper represents the research result of a project supported by the National Natural Science Foundation Grant No. 4870132
文摘Located at the southern margin of the South China plate, the Youjiang basin is a closely related to the NW- and NE-trending syndepositional faults in respect to the configuration and structure of the basin. The evolution of the Youjiang basin progressed through two stages. In the Hercynian period, the opening of the Ailaoshan-Honghe ocean basin gave rise to a number of NW-trending rift belts in the Youjiang area. During this period, deep-water sediments were dominant and the basin was possesed of the characteristics of the rift system of passive continental margins. In the early Indosinian after the Dongwu movement, the circum - Pacific tectonism led to a major change in the configuration and structure of the basin. In the meantime, the Ailaoshan ocean basin began to be subducted towards the northeast, thus causing the basin to be split and expand again, and then the basin developed into the stage of the back -arc basin. At the end of the Indosinian period, the basin gradually closed from east to west, thus ending up the history of development of the Youjiang basin. In the various developmental stages, sediments in the basin, also limited by the Dongwu movement, were formed by superposition of sedimentation systems with different features, and a typical two-layered structure, which consisted of starved and compensated sediments, also occurred in the early stage. Likewise, volcanic activity in the basin involved two stages. Basin volcanic rocks of alkali and alkali-calcic series, which were controlled by NW-trending faults, occurred in the early stage, and basic and intermediate-acid volcanic rocks of calc-alkali and calcic series, which were controlled by NW- and NE-trending faults. From the above it follows that the Youjiang basin was formed by the combined action of the Palaeotethys and circum -Pacific tectonism.
