为更好理解燕山带的构造,作者在燕山地区开展了构造填图。在近年的构造填图中于辽宁省绥中县永安堡地区识别出大型的构造窗,其原始的逆掩推覆构造系统上盘由太古宇片麻岩及上覆岩系组成,而下盘由强烈韧性变形的张家口组火山岩系组成。填图结果表明,永安堡地区并不是一个张家口组岩层形成的宽缓向斜,也不是大型古火山机构。燕山地区在早白垩世张家口组火山岩喷发之后仍然存在强烈的区域挤压变形作用。基于野外观察和填图工作,我们认为国内已发表的地质图件未能真实反映燕山带的区域构造基本特征。
For the purpose of understanding the Mesozoic tectonics of Yanshan belt, the authors carried out geological mapping in this belt. During the mapping, a large-scale thrust structure was identified in Yong′ anpu area, western part of Suizhong County, Liaoning Province. The hanging wall of the thrust is composed of Archean gneiss and the overlying strata,and the strongly ductile deformed volcanic rocks of Early Cretaceous Zhangjiakou Formation comprise the foot-wall in Yong" anpu inlier. The mapping indicates that there exists no "ancient volcanic apparatus" in Yong'anpu area, and that the struc- ture of Yong'anpu area is not an open syncline of Zhangjiakou Formation. However, there does exist a strongly compres-sional detbrmation in Yanshan belt after the eruption of Early Cretaceous Zhangjiakou volcanic rocks. Based on the authors" mapping and research, it can be concluded that the geological maps published by geologists in China have failed to identify major structural features of Yanshan belt.