小秦岭地体边缘断裂特征及其演化

THE CHARACTERISTICS AND EVOLUTIONARY OF MARGINAL FAULT IN THE XIAOQINLING TERRAIN

本文论述了小秦岭地体边缘断裂三个阶段４期活动的构造特征和演化过程。阐明了断裂带在地壳伸展作用下孕育了第一阶段的正韧性剪切；在地壳收缩作用下的第二阶段完成了韧性推覆到脆性仰冲的转化；而在地壳引张应力场中的第三阶段发生了脆性正断作用。断裂的多期活动形成了小秦岭地区的盆岭构造格架。

In this paper,the tectonic characteristics and evolutionary process of marginal faults in theXiaoqinling terrain which can be devided into three stages and four active events have been dis-cussed.The first positive ductile shear stage was developed during the crustal extension in thefault zone,while the transformation from ductile nappe to brittle overriding was finished in thesecond crustal contraction stage,The brittle positive fault was developed in crustal extensionstress field which is called third stage,The frame-work of basin-range structure in the Xiacoin-ling was formed during the mutiple fault actions.