冀北辽西地区构造形迹的新认识  

THE STRUCTURE STYLE OF NORTH HEBEI AND THE WESTERN LIAONING

作　　者：林晓辉[1] 秦正永[1] 

机构地区：[1]天津地质矿产研究所,天津300170

出　　处：《地质找矿论丛》2003年第2期78-83,共6页Contributions to Geology and Mineral Resources Research

摘　　要：　冀北辽西地区的盖层可分两个构造层,由燕辽复向斜和秦皇岛背形相互叠加,并相应发育两期推覆构造。复向斜范围包括内蒙古地轴和燕辽沉降带,是由长条形的3个背斜和2个向斜相间,及配套的EW向纵断裂、SN向横断裂和NE向、NW向的共轭断裂组成。著名的尚义—宽城—凌源—朝阳—北票断裂是复向斜及其次级背斜的轴部纵断裂,以南大岭组、窑坡组和北票组作为其裂隙充填物。燕山EW向断裂南北对冲现象是复向斜纵断裂放射状排列并向核部推覆的反映。秦皇岛背形以秦皇岛—凌源断裂为轴面,由复向斜的轴面褶皱而成,背形转折端在秦皇岛,呈相对上翘。本区NE向、NNE向断裂的叠加在区域上有不同的表现:冀北段NE向、NNE向褶皱叠加的结果使燕山段复向斜成为短轴褶皱样式,平面图呈NW向排列,符合Ramsay第一类褶皱干涉样式的第二种类型。复向斜的形成机制完全符合纵弯褶皱作用下岩石的变形原理,是西伯利亚板块和华北板块碰撞的结果;秦皇岛背形的形成是后期太平洋板块俯冲在欧亚板块之下所致。The cover column of JibeiLiaoxi area consists of two structural layers. The Yanliao synclinorium and Qinhuangdao antiform are overprinted with each other and the two stage naps corresponded to them are developed. The synclinorium zone includes lnner mongolia geoaxis and Yanliao depression belt and comprises the alternated 3 anticlines and 2 synclines and the correspondant EW longitudinal fractures, SN latitudinal fractures and NWcongjugate fractures. The well known ShangyiKuanchengLing yuanChaoyangBeipiao fracture is an axial longitudinal fracture of the synclinorium and the subscale anticlines in which the Nandaling formation, Yaopo formation and Beipiao formation were formed. Opositive movement from the south and north for the EW fiactures is the response to radiate arrangeonent of longitudinal fractures of synclinorium and overthrusting to the core. Qinhuangdao antiform is formed by folding of the axial plane of the synclinorium with the hinge located at Qinhuangdao. Superimposition of NE and NNE fractures is regionally varied. In Jibei domain the superimposition lead to brachyfolds at Yanshan area showing NW arrangement in plan and reconstructing into the second Ramsay's style fold. Mechanism of the synclinorium is completely coincided with the rock deformation under the longitudinal bending and the synclinorium is resulted from collision of the north China plate and Siberia plate and Qinhuangdao antiform from the subduction of pacific plate under Eurasian plate.

关 键 词：燕辽复向斜 秦皇岛背形 轴部纵断裂 裂隙充填物 凌源一秦皇岛断裂 纵弯褶皱作用 冀北辽西地区 

分 类 号：P548[天文地球—构造地质学]