陕南镇巴地区大巴山与米仓山构造交接关系

Tectonic intersection relationship between Dabashan and Micangshan in Zhenba area,southern Shaanxi Province

裴先治 李瑞保 丁仨平 刘战庆 李佐臣 冯建赟 孙雨 张亚峰

Pei Xianzhi Li Ruibao Ding Saping Liu Zhanqing Li Zuochen Feng Jianyun Sun Yu Zhang Yafeng

米仓山与大巴山构造交接的陕南镇巴地区具有典型的叠加褶皱构造。米仓山地区近东西-北东东向褶皱构造与大巴山近南北-北北东向紧闭褶皱构造呈横跨叠加构造样式。司上地区发育的叠加褶皱表明,近南北向褶皱叠加改造早期近东西向褶皱,致使区域地层呈近南北向产出;两期褶皱发育的时代应为J—K,米仓山褶皱变形的时间要略早于南大巴山西段镇巴地区变形时间,分别为晚侏罗世(J)和晚侏罗世—早白垩世之间(J/K)。大巴山与米仓山构造交接变形是在印支期碰撞造山作用基础上,燕山期陆内造山作用期间不同体系构造复合叠加的产物。

Typical superimposed fold structure occurs in the Zhengba region,southern Shaanxi Province,where the Micangshan and Dabashan structures intersect with each other.The nearly EW-NEE trending fold structures in Micangshan area and the nearly SN-NNE trending closed fold structures in Dabashan area are in traverse superimposition.The superimposed folds developed in the Sishang area show that the early E-W trending folds were superimposed and deformed by the late S-N trending folds,resulting in the nearly S-N occurrence of the regional strata.These folds were developed during J-K.However,the folding and deformation of the Micangshan area happened in the Late Jurassic(J),a little earlier than that of the Zhenba area(the west segment of the sou-thern Dabashan Mountain),which happened during the Late Jurassic and Early Cretaceous(J/K).The intersection and deformation of Dabashan and Micangshan were resulted from superimposition of different tectonic systems during the Yanshanian intracontinental orogeny on the basis of the Indosinian collision orogeny.

10.11743/ogg20090507