Abstract: The Mesozoic paleomagnetic pole positions from the Indochina block and South China block are not consistent with each other in that the formers are displaced with respect to the latters westward in longitude and southward in latitude. The displacement is here interpreted as to be related to the India-Eurasia collision in such a way that after the collision the Indochina block was rotated clockwise by 8? about the Assam syntaxis, followed by an eastward translation of the South China block by about 20?. This interpretation is in accord with the propagating extrusion tectonics model, and suggests that the sense of motion along the Red River fault has reversed, i. e., changed from the early left-lateral to the present right-lateral.

Key words: South China block, Indochina block, Red River fault, Propagating extrusion tectonics, Paleo- magnetism, Euler rotation

摘要： 印支地块中生代的古地极位置较华南地块的古地极位置经度偏西、纬度偏南。此现象系印度板块和欧亚板块碰撞后,先是印支地块绕喜马拉雅山系的东枢纽(阿萨姆枢纽)顺时针转动了8°,然后华南地块自西向东移动了大约20°。此解释与主走滑断层迁移模式基本吻合。古地磁数据还表明,虽然红河断裂近期活动为右旋性质,但在印度板块和欧亚板块碰撞初期,它曾是一条调节两板块相互作用的巨大的左旋走滑断层。

关键词: 华南地块, 印支地块, 红河断裂带, 走滑断层, 古地磁, 欧拉转动