反转构造与其易混淆构造的对比分析

比较分析负反转断层与"跷跷板"式构造,正反转褶皱与重力滑动堑背形、地层补偿堑背形及底辟背形,断展型正反转与滚动背斜的构造形态特征。负反转断层与"跷跷板"式构造外部形态都呈现出反向的楔形,但是后者是在统一的区域应力场下,由断层活动性质的横向差异所致。正反转褶皱与背形构造外部形态都呈现出背形,但是在地层厚度、剥蚀程度、轴面及伴生构造等方面存在差异。前者地层中间厚两翼薄,顶部剥蚀程度向两翼降低,不整合面之上的地层向褶皱高点超覆。重力滑动堑背形由于是区域性张应力的大环境下局部受压的结果,所以其规模较小;重力滑动堑背形和地层补偿堑背形地层受张性区域应力控制,地层顶部无剥蚀,且无中间厚两翼薄的特征;底辟背形无横向应力,属横弯褶皱,轴面多直立,发育盐边凹陷及顶部断层簇等伴生构造。断展型正反转与滚动背斜均是断层的上盘发育背斜,但在背斜的形态、规模、地层厚度等方面存在差异。滚动背斜受同生断层控制,背斜面积和高度较小,轴面基本平行于断层面;顶部地层剥蚀不明显;与断展型正反转地层厚度呈上凸下凹的"喇叭型"相比,其地层厚度横向变化小。

Comparative Analysis of Inversion Structure with Its Easily Confused Structures

Comparisons between negative inversion faults and the "seesaw" structures,positive inversion folds and gravity slide-shaped graben antiforms,layer compensation antiforms and diapirs antiforms,positive inversion faults-propagation and the rollover anticlines are discussed.Negative inversion faults and the "seesaw" structures have the similar external form of a reverse wedge,but the latter is formed by different fault activity in a unified regional stress field.Positive inversion folds and antiforms have similar profiles,but are different in the strata thickness,erosion degree,axial face,and associated structures.The former's strata are thick in the middle but thin in wings,and strata denudation thickness is lower in the wings,and it's strata overlap to the fold center above the unconformity.Gravity slide-shaped graben antiforms and layer compensation antiforms are under the control of regional tensile stress,so there is no erosion at the top of the strata,and no characteristics of middle strata thick but wings thin.Gravity slide-shaped graben antiform is the result of local pressure in regional tensile stress,so its size is small.Diapirs antiform is cross-bend fold with lateral stress-free,so its axial is always upright,and its associated structures such as depression of salt side and the top faults cluster are developed.Positive inversion faults-propagation and rollover anticline both develop anticlines on the fault hanging wall,but their anticline shapes,sizes,and strata thickness characters are different.Rollover anticline is controlled by contemporaneous faults,so its anticline area is small and height is little,and its axial basically parallels to the fault plane.Its denudation is not obvious at the top of strata and its strata thickness varies small laterally compared to the concave-convex "horn-type" strata of positive inversion faults-propagation.