在《印度洋底大地构造图》的基础上,分析了印度洋盆构造格局和洋盆演化重大事件序列,并从印度洋盆初始裂解机制、扩张中心跃迁与热点作用、洋中脊扩展作用等方面讨论了印度洋盆的张开过程,提出以下几点认识:(1)现今印度洋洋中脊可分为两个系统:东南印度洋中脊-中印度洋中脊-卡斯伯格洋脊系统(东支)和西南印度洋中脊系统(西支),前者是太平洋洋中脊扩展作用的产物,后者是太平洋-东南印度洋中脊与大西洋中脊之间构造调节的产物;(2)印度洋盆最初裂解受地幔柱垂向挤压-水平伸展作用控制,沿前寒武造山带等地壳薄弱带发育;(3)印度洋盆经历两次扩张中心的跃迁,其趋向性跃迁方向与热点相对板块的运动方向具有一致性,显示两者存在内在联系.(4)大西洋和太平洋洋中脊在印度洋交汇,于古近纪连通,末端伴随陆块持续发生碎裂化、裂解化,可称为鱼尾构造模式,表明印度洋盆衔接和调节了三大洋盆的发育和演化过程,具有全球洋盆枢纽的关键意义.%This paper is based on the compilation of the Indian Ocean Tectonic Map and the analyses of the tectonic pattern and significant tectonic events of Indian Ocean. Three problems are further discussed concerning the initial breakup mechanism of Indian Ocean, ridge jump and hotspots, and mid-ocean ridge extension. We draw the following conclusions:1) The Indian mid-ocean ridges can be divided into two systems: Southeast Indian Ridge-central Indian Ridge-Carlsberg Ridge (East Branch), and Southwest Indian Ridge (West Branch). The former system is the product of Pacific Ocean Ridge system extension. The latter one is the product of the tectonic adjustment of Pacific-Southeast Indian Ridge system and Atlantic Ocean ridge system. 2) The initial breakup was controlled by vertical compression-horizontal extension and developed along pre-Cambrian orogen. 3) Indian Ocean experienced two major ridge jump processes. The directions of ridge jump and hotspot movement are consistent, illustrating internal connection of the two tectonic processes. 4) The Atlantic and Pacific mid-ocean ridge systems joined in Indian Ocean in Paleogene. Its terminal was continuously fragmented. This can be called Fish-Tail Tectonics, which illustrates that Indian Ocean links up and adjusts the development of three major ocean basins. The Indian Ocean is therefore a key hinge of global oceanic basins.
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