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南大巴山是一个形成于T_3—K_1，滑脱深度小于8-10km的扬子板块北缘薄皮冲断锲。它主要由发育在显生宙地层中台阶状逆断层及断层相关褶皱构成的边冲岩席、双重推覆体和冲起构造等组成。变形扩展以前列式为主。经平衡地质剖面制作，因冲断南大巴山地壳缩短率平均达49．3％。并以每年约1．28mm的速率总体缩短约64km。它的成因受控于秦岭碰撞造山过程中扬子板块北缘A型俯冲所提供挤压应力，在向南扩展时，由于古大陆边缘形态不一所诱发的右旋剪切挤压动力学机制。
South Dabashan is a thin-skinned thrusting wedge formed on the northern margin of the Yangtze plate, formed at T_3-K_1 with a slip depth less than 8-10 km. It is mainly composed of the side-punch rock seats, double nappe bodies and rhyolite structures, which are formed by step reverse faults and fault-related folds in the Phanerozoic strata. Deformation expansion to the main formula. After balanced geologic profiling, the crustal shortening rate due to thrusting of South Daba Mountain averaged 49.3%. And overall shortens about 64km at a rate of about 1.28mm per year. Its origin is controlled by the compressive stress provided by the A-type subduction at the northern margin of the Yangtze plate during the collision orogen of the Qinling Mountains. When it expands southward, the dynamic mechanism of dextral shear-extrusion due to the different shapes of the ancient continental margins can be obtained.