黄骅坳陷褶皱分类及成因分析

黄骅坳陷内多数褶皱都是在伸展构造背景下形成的，并与正断层系统紧密联系在一起。根据褶皱枢纽与断层走向的位置关系，黄骅坳陷内褶皱样式基本类型大体可以分为纵向褶皱和横向褶皱。根据褶皱的形成机制，这两种褶皱又可进一步分为牵引褶皱、逆牵引褶皱、滚动褶皱、翘倾式背斜、断层位移褶皱、断线转向褶皱以及叠加形成的各种复式褶皱。这些褶皱受构造演化控制，可互相转化。另外，黄骅坳陷内还存在多种成因与反转断层相关的褶皱。

STYLES AND ORIGIN OF FOLDS IN HUANGHUA DEPRESSION

Most folds were formed in extensional settings in Huanghua depression, and firmly associated with normal fault systems. The folds can be classified into two styles of longitudinal folds and transverse folds. The fomer hinges are parallel or subparallel to the associated faults, the latter hinges are oriented at a high angle or perpendicular to the related normal faults.Depending on the difference in fundamental mechanism, the folds can be further classified into drag folds, reverse drag folds, rollover folds(rollover anticlines), tilting folds, fault displacement folds, fault line deflection folds and other types of superimposed folds. Simultaneously, these folds are under the control of structural evolution, and can be mutually transformed. In addition,there are some folds associated with inversion fault in Huanghua depression.