菲律宾海板块东南边界地质过程与研究展望

Geological evolution and research prospect in southeast boundary of Philippine Sea Plate

  • 摘要: 晚中生代期间,由于古太平洋俯冲板片俯冲于欧亚板块之下,从而在欧亚大陆东缘存在一条巨型的类似于现今太平洋东侧的安第斯型俯冲带。岩浆活动记录显示,70 Ma左右,可能由于外来的正地形地体拼贴上该俯冲带,从而导致这条巨型安第斯型俯冲带逐渐消失,欧亚大陆东缘逐渐从主动大陆边缘变为被动大陆边缘。然而,新生代早期以来,伴随着菲律宾海板块从赤道北移,该被动大陆边缘又重新活化,变为主动大陆边缘,并逐渐形成了巨型的沟-弧-盆系统,期间西太平洋地区大致经历了三期的弧后扩张,即始新世、渐新世—中新世、上新世以来,且菲律宾海板块正好包括了这3个扩张期的弧后扩张盆地:西菲律宾海盆、四国海盆-帕里西维拉海盆以及马里亚纳海槽。本文详细总结了太平洋板块与次级的板块—菲律宾海板块及卡罗琳板块的地质演化历史,且详细探讨了以上3个主要板块之间相互作用的典型区域(菲律宾海板块东南侧)的地质学和岩石学特征以及尚存在的重要科学问题,并展望了未来该区域的研究方向。

     

    Abstract: During the Mesozoic Era, due to continuous subduction of the plaeo-Pacific slab beneath the Eurasian plate, a huge Andean-type subduction zone was gradually formed, being similar to that in modern eastern Pacific margin. Evidence from magmatic activity shows that the subduction processes of the Mesozoic Andean-type subduction zone had gradually ceased due to possible collaging of exotic positive topography terrane (s) into the subduction zone, and the eastern margin of the Eurasian plate has changed from active to passive continental margins. However, since early Cenozoic, accompanied by northward migration of the Philippine plate from south of the Equator (original place), the passive margin was reactivated and became an active margin and gradually formed a huge trench-arc-(back-arc) basin system in the western Pacific region after experienced three-epoch spreading evolution (i.e., Eocene, Oligocene-Miocene, Pliocence-Present). The Philippine Sea plate (PSP) includes these three-epoch back-arc basins (i.e., West Philippine Basin, Shikoku-Parece Vela Basins, and Mariana Trough). This study summarized in detail the geological evolution history of Pacific plate (first-order large tectonic plate), Philippine Sea plate and Caroline plate (second-order tectonic plate), described the geological and petrological characteristics for typical regions of interaction of the three tectonic plates, proposed some important scientific questions, and finally, pointed out the directions of investigation and research in the near future.

     

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