藏北高原主要断裂带电性结构特征

对600线的部分测点及2100线的全部测点构成的五道梁-绿草山大地电磁深探测剖面进行了二维非线性共轭梯度反演,得到青藏高原中北部二维电性结构模型.根据该电性结构模型,结合研究区域重、磁及区域地质资料推断了青藏高原中北部主要断裂的位置、产状和切割深度等信息.研究结果表明,青藏高原中北部发育有F1-F16一系列深断裂.其中,F1(苟鲁山克错-囊谦断裂带)和F9(乌兰乌拉湖-玉树断裂带)共同构成金沙江缝合带的北界,是松潘-甘孜-可可西里地块与羌塘-唐古拉地块的分界线;F4、F10-F12共同构成昆仑断裂带,F4(阿尼玛卿断裂带)是南部松潘-甘孜-可可西里地体和北部北昆仑-柴达木地体的分界线;F6、F13-F16为柴北缘断裂带,由南倾的岩石圈深断裂F6和一系列产状相背、北倾的逆冲断裂F13-F16所构成;F7和F8可能反映岩石圈内产状平缓、隐伏的滑脱构造形迹.

Electrical features of the main faults beneath Northern Tibetan Plateau

The resistivity model of central-north Tibet was obtained by 2D nonlinear conjugate gradients inversion with the data from Wudaoliang-Lvcaoshan magnetotelluric deep sounding profile, which consisted of partial sites from line 600 and all sites from line 2100. The features of the main faults beneath central-north Tibet were deduced according to this model as well as regional gravity, aero-magnetic and geological survey. The research results suggest that, there are sixteen faults, named F1 to F16 beneath central-north Tibet. Moreover, F1 (Julushankecuo-Nangqian fault belt) and F9(Wulanwulahu-Yushu fault belt) are the northern edge of Jinshajiang suture, and the border between Songpan-Ganzi-Kekexili block and Qiangtang-Tanggula block. Kunlun fault zone consists of F4, F10 to F12. F4(Animaqin faults belt)is the border between Songpan-Ganzi-Kekexili block in the south and Kunlun-Qaidam block in the north. The northern edge fault zone of Qaidam basin consists of F6, F13 to F16, furthermore, F6 dips to south and penetrated the crust, F13 to F16 are a series of thrust faults dipping to north oppositely.