热点作用背景下的洋中脊跃迁和扩展作用:印度洋盆地张开过程探讨

发布时间：2018-10-09 17:21

【摘要】：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。
[Abstract]:Based on the Geotectonic Map of the bottom of the Indian Ocean, the tectonic pattern of the Indian Ocean basin and the sequence of major events in the evolution of the ocean basin are analyzed, and from the initial splitting mechanism of the Indian Ocean basin, the transition of the spreading center and the role of the hot spots are discussed. The spreading process of the Indian Ocean basin is discussed in this paper. The main conclusions are as follows: (1) the present mid-ocean ridge of India can be divided into two systems: the mid-southeast Indian Ridge, the Central Indian Rib and the Casberg Ridge system (Eastern Branch) and the South-West Indian Ocean Central Ridge system (Western Branch). The former is too Central Indian Ocean Ridge system. The product of the spreading of the mid-ocean ridge, The latter is the product of tectonic adjustment between the mid-Pacific and mid-Atlantic ridges. (2) the initial fragmentation of the Indian Ocean basin is controlled by the vertical compression-horizontal extension of mantle plumes. The weak crustal zones along the Precambrian orogenic belt have developed. (3) the Indian Ocean basin has experienced two transitions of the spreading center, and its tendency transition direction is consistent with the movement direction of the hot spots relative to the plate. (4) the Atlantic and Pacific ridges meet in the Indian Ocean and are connected in the Paleogene. The end of the oceanic ridges is continuously fragmented and cracked with the continental block, which can be called the fishtail tectonic model. The results show that the Indian Ocean basin connects and regulates the development and evolution of the three ocean basins, which is of key significance to the global ocean basin hub.
【作者单位】：北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室;国家海洋局海底科学重点实验室国家海洋局第二海洋研究所;
【基金】：印度洋脊多金属硫化物成矿潜力与资源环境评价(DY125-12-R-03) 西南印度洋脊合同区多金属硫化物资源评价(DY125-11-R-01)
【分类号】：P736.1

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