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早期对燕山构造带三叠系不同岩性组时代的确定主要根据植物化石和区域岩性对比,认为刘家沟组与和尚沟组为下三叠统,二马营组为中三叠统.通过对承德下板城盆地和平泉营子盆地三叠系砂岩碎屑锆石年龄分析,本次研究揭示刘家沟组、和尚沟组和二马营组皆为上三叠统.砂岩碎屑锆石年龄还揭示,早期认为属于中-上二叠统石盒子组的上段和上覆孙家沟组实属早三叠世末-中三叠世沉积.本文将石盒子组上段与孙家沟组合并,新命名为营子组;同时用丁家沟组、下板城组和胡杖子组分别替换现在使用的刘家沟组、和尚沟组和二马营组.野外地层和岩相分析证明,石盒子组上部安山岩层的顶面是一个沉积间断面,标记了中二叠统与下-中三叠统之间为平行不整合接触.营子组曲流河沉积指示在早三叠世末-中三叠世构造活动处于相对平静期,而上三叠统丁家沟组和胡杖子组砂质/砾质辫状河、冲积扇、扇三角洲、深湖沉积与火山岩组合代表强烈伸展断陷活动.新的三叠系地层划分、时代限定和沉积过程恢复对深入了解早中生代燕山构造带演化具有重要意义.
The early identification of the age of the Triassic different lithology groups in the Yanshan tectonic belt was mainly based on the comparison of plant fossils and regional lithologies. It is considered that the Liujiagou Formation and the Hezhanggou Formation are the Lower Triassic, and the Ermaoying Formation is the Middle Triassic. Based on the zircon age analysis of the Triassic sandstone in the Lower Bancheng basin and the Pingquan-Yingzi basin in Chengde, this study reveals that the Liujiagou, Hevshangou and Ermaying formations are all Upper Triassic. Sandstone detritus The zircon age also revealed that the upper part of the upper-middle Permian Shihezi Formation and the overlying Sunjiagou Formation were deposited from the end of the Early Triassic to the Middle Triassic, The ditch group was merged and renamed Yingying Formation, while the currently used Liujiagou Formation, He Shanggou Formation and Ermaying Formation were replaced by Dingjiagou Formation, Xiabancheng Formation and Huzhangzi Formation, respectively. The analysis shows that the top of Anshan formation in Shihezi Formation is a sedimentary discontinuity, which indicates the parallel unconformity contact between the Middle Permian and the Lower-Middle Triassic.The Yingzi Formation meandering sediments indicate that during the Early Triassic Late Moutain-Middle Triassic tectonic activities in a relatively calm period, and the Upper Triassic Dingjiagou group and Hu stick Sandstone / gravel braided river, alluvial fan, fan delta, deep lacustrine sediments and volcanic rocks represent strong extensional faulting activities.The new Triassic stratigraphic division, age limitation and depositional process restoration are of great importance to the understanding of the Early Mesozoic Yanshanian structure With the evolution of great significance.