藏北高原主要断裂带电性结构特征

Electrical features of the main faults beneath Northern Tibetan Plateau

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.

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.