辽西牛营子地区晚三叠世逆冲构造

燕山陆内造山带侏罗纪的构造及其研究已广为报道，但确凿的三叠纪构造分析明显不足，对辽西凌源牛营子地区详细的构造地质调查揭示该区晚三叠世晚期存在的逆冲构造，盆地东部中侏罗世郭家店组之下覆盖着一套晚三叠世逆冲叠瓦构造，其运动指向，黄土坡以西逆冲叠瓦构造由西向东推覆；黄土坡以北弧形断裂由北向南逆冲，为派生的运动。逆冲断裂带控制的槽地之中发育同逆冲期邓杖子组灰岩－－白云岩质角砾砾岩，我们的资料表明，对杖子组时代应属晚三叠世晚期，与晚三叠世老虎沟组基本是连续过渡的，原定牛营子盆地早－中侏罗世地层是倒置的，正常的晚三叠世－中侏罗世地层序列自下而上应为老虎沟组，邓杖子组，水泉沟组，郭家店组，晚三叠世晚期逆冲构造事实的确定说明，燕山陆内造山带至少从晚三叠世起就经历了强烈的变形，其早期形变历史对于认识区域构造演化和陆内变形的发展过程具有重要意义。

Late Triassic Thrusting in the Niuyingzi Region, Western Liaoning, China

Our recent structural survey of the Niuyingzi region, western Liaoning shows that there exist a thrust of the latest Triassic age, which is covered by the Middle Jurassic Guojiadian formation in the eastern Niuyingzi region. The directions of thrusting are toward the east for the principal imbricated sheets just west of Huangtupo and toward the south for the local arcuate thrust just north of Huangtupo. There occur synthrusting sediments, the Dengzhangzi formation along a trough-like basin, which was controlled by the thrust fault zone. The Dengzhangzi formation is composed of brecciated lime-dolomitic conglomerate. The stratigraphic sequence and structure of the strata confirm that the age of the Dengzhangzi formation is of latest Triassic. It can be observed that the Late Triassic Laohugou formation is transitional to the Dengzhangzi formation successively. Therefore the Late Triassic to Middle Jurassic stratigraphic sequence in the ascending order is the Laohugou formation, Dengzhangzi formation, Shuiquangou formation and Guojiadian formation in this region, instead of the previous reversed order. The confirmation of the thrust system developed in the Late Triassic in this region provides the key evidence to understanding the early stage of the deformational history of the Yanshan intracontinental oro-genic belt.