湖北大冶地区板内变形及构造应力场的初步研究

PRILIMINARY STUDY ON THE INTRAPLATE DEFORFATION AND TECTONIC STRESS FIELD OF THE DAYE REGION, HUBEI

位于杨子板块北缘的湖北大冶地区，印支运动后进入复杂的板内变形阶段。印支阶段（２２４－１９５Ｍａ）近南北向挤压产生了１３．１％的板内收缩率；燕山一阶段（１９５～１５０Ｍａ）ＳＥＥ—ＮＷＷ挤压而产生１１．７％的板内收缩率；燕山二阶段（１５～１００Ｍａ）自南而北挤压产生２２．０％的板内收缩率；燕山三阶段（１１０—２５Ｍａ）南北向的板内拉伸率大于３．７％。印支运动形成东西向开阔褶皱，燕山二阶段剧烈的构造运动形成区域性轴面南倾褶皱、倒转褶皱以及一系列北冲道断层，构成该区基本构造格局。

The Daye region in Hubei, located in the northeast margin of Yangtze platze,had undergone a complex intraplate deformation after Indosinian movement. First, the intraplatecontraction rate was 13. 1 % by compression in S - N direction during Indosinian stage (224 ～195Ma). Next, the contraction rate was 11. 7 % by a SEE NWW compressive process during the first Yanshania stage (195 ～ 150Ma). After that, the contraction rate becames 22. 0% by a strong compressive process during the second Yanshania stage (150 ～ 100Ma). Finally, the intraplate extension rate was 3.7% by a S N extensional process during the third Yanshanion stage. The open folds in E - W strike formed in Indosinian movement and the inclined folds with their axial planes dipping south, overturned folds and a series of reverse faults thrusting to north formed in the second Yanshania stage constitute the fundamental tectonic framework in this area.