太要断裂东段覆盖区地球物理特征及推断解释

通过对小秦岭北麓黄土覆盖区重力测量、音频大地电磁测深（AMT）、可控源音频大地电磁测深（CSAMT）、二维地震等物探勘查资料进行分析、处理和综合研究，总结了太要断裂东段的深部特征和分布形态。研究认为：太要断裂东段沿小秦岭北麓近东西向呈波状展布，断裂具有分枝复合现象，主断层处在盆地内黄土覆盖区；断裂为高角度正断层，倾角为65°~80°，总断距在3 000 m左右；断裂错断了中、新生界和太华群内的韧性剪切带，对矿体具有破坏作用；太要断裂主要发育期始于中生代晚白垩世以后，晚于小秦岭变质核杂岩的拆离断层发育形成时间。

Geophysical Characteristics of Loess-covered Area in the Eastern Segment of Taiyao Fault,Xiaoqinling Mountains

After carrying out the gravity survey, Audio Magnetotelluric sounding (AMT), Controlled Source Audio-frequency Magnetotelluric sounding (CSAMT), 2D seismic survey in the loess covered area of the north Xiaoqinling Mountains, the related data has been analyzed, processed and comprehensively studied in this paper. And then, the deep fracture characteristics and distribution pattern of eastern segment of Taiyao fault have been summarized. The result shows that the eastern segment of Taiyao fault extends in near EW direction, showing wavy distribution along the north Xiaoqinling Mountains and having the phenomenon of separation and reunion. The main fault is located in the loess covered area of the basin, which belongs to the high-angle normal fault, with the inclination of 65°-80ånd the total fault displacement of about 3000 m. This fault dislocates the Mesozoic and Cenozoic strata, as well as the ductile shear zone in the Taihua Group, which destroys the gold deposit. The Taiyao fault was mainly developed after late Cretaceous, which is later than the formation of detachment fault of metamorphic core complex in Xiaoqinling Mountains.