北祁连地体古地磁新数据及古生代地体南向位移事件的发现

THE SOUTHWARD MOVEMENT IN PALAEOZOIC ERA FROM NEW PALAEOMAGNETIC DATA OF NORTH QILIAN TERRANE

格尔木－额济纳旗地学断面古地磁学研究工作中，在北祁连地体上获得了８个古生代、中生代古地磁新数据。研究结果在明北祁连地体在古生代一直处于北纬低纬度（１０°～１７°Ｎ）地区，并且表现出于古生代明显的南向位移过程。南移幅度为５．５°左右。这与北祁连地区原始陆壳在中奥陶世的强烈拉张及其后期洋壳闭合作用有关。

Through palaeomagnetic study of North Qilian terrane tectonics in geoscience transection from Golmud to Ejina banner,eight new palaeomagnetic data of palaeozoic and Mesozoic Era are obtained and it is indicated that North Qilian had been located in low latitude area North latitude (10°～17°degrees)during palaeozoic. In palaeozoic,terrane showed an episode of evident southward movement,which began at early silurian and ended at early carboniferous.Up to late permian,the terrane began to return.The amplitude of southern movement is about 5. 5 degrees.It may be relative to extension of the primitive continental crust in North Qilian area in middle ordovician and its filing and welding of later period.