扬子板块、澳大利亚板块、印度板块在新元古代晚期(750~540 Ma)古板块再造:来自古地磁制约

Reconstruction of the Yangtze,Australian and Indian plates in the Late Neoproterozoic (750-540Ma) using paleomagnetic constraints

扬子板块在新元古代时期作为Rodinia超大陆的重要组成部分,其位置一直存在争议。为探讨扬子板块在新元古代晚期的位置,综合前人发表过的古地磁数据,利用古地磁研究方法,对扬子板块与澳大利亚板块、印度板块在新元古代晚期的相对位置关系进行研究。根据地层对比、锆石测年等诸多证据,将扬子板块置于印度板块北缘(现今位置)、澳大利亚板块西北缘(现今位置)。基于扬子、印度、澳大利亚运动学特征分析,认为扬子板块在Rodinia超大陆裂解时运动至高纬度地区,750~635 Ma期间,扬子板块处于中高纬度地区,在635 Ma时开始快速向低纬度地区运动。虽然将扬子置于印度北缘,但认为二者并不相连,而是到了570 Ma左右发生碰撞后连接到一起,并一同加入冈瓦纳大陆。

As an important part of the Rodinia supercontinent in the Neoproterozoic, the position of the Yangtze Plate has always been a hot research topic. In order to discuss the position of the Yangtze Plate in the Late Neoproterozoic(750-540 Ma), the relative positions of the Yangtze, Australian and Indian plates in the Late Neoproterozoic(750-540 Ma) are studied by combining the previously published paleomagnetic data and using the paleomagnetic research method. Based on the stratigraphic correlation, zircon dating and other evidences, the Yangtze Plate is placed in the present-day northern margin of the Indian Plate and the northwestern margin of the Australian Plate. Based on the analysis of the kinematic characteristics of Yangtze, India and Australia, it is considered that the Yangtze Plate moves to the high latitude area during the breakup of the Rodinia supercontinent. During the period of 750-635 Ma, the Yangtze Plate is in the middle-high latitude areas, and it starts to move rapidly toward the low latitude area at 635 Ma. Although Yangtze is placed on the northern rim of India, the two plates are not thought to be connected, until after their collision at around 570 Ma and both join Gondwana.