论文部分内容阅读
内蒙古大青山地区侏罗纪地层发育齐全 ,下、中侏罗统五当沟组为一套含煤碎屑沉积 ,中侏罗统长汉沟组为灰绿色粉细砂岩夹灰岩及砂砾岩 ,中、上侏罗统大青山组为紫色碎屑岩系 ,构成了一个完整的盆地演化序列。由于区内中生代逆冲推覆构造极其发育 ,使得区内不同时代的地层均呈构造岩片相互叠置 ,给地层划分和对比带来许多困难 ,前人所划分的中、上侏罗统大青山组 ,其中绝大部分并非大青山组 ,而是上二叠统脑包沟组和下白垩统李三沟组及固阳组。通过大量的野外调查工作 ,笔者对区内大青山组的地层层序、展布规律以及与下伏地层的接触关系性质等都重新给予厘定 ,提出大青山地区上侏罗统大青山组为一套干旱炎热气候条件下的河湖相沉积、生物贫乏 ,分布严格受坝岩—席麻湾—金銮殿断裂控制 ,与下伏地层局部呈不整合 ,整体呈假整合接触 ,这些结论对区内地层划分、对比以及地质演化历史的研究具有重要意义。
The Jurassic strata in the Daqingshan area of Inner Mongolia are well developed. The middle and lower Jurassic Wudanggou Formation is a set of coal-bearing clastic sediments. The Middle Jurassic Changhangou Formation is a greyish-green silty sandstone sandstone and conglomerate The Middle Jurassic Daqingshan Formation is a purple clastic rock series, forming a complete sequence of basin evolution. Because the Mesozoic thrust nappe structure is extremely developed in the region, the strata of different ages in the area are all superimposed by tectonic slices, which brings about many difficulties in stratigraphic division and comparison. The Daqing Mountains of the Middle and Upper Jurassic Most of which are not the Daqingshan Formation but the Upper Permian Naoobaogou Formation and the Lower Cretaceous Li Sangou Formation and the Guyang Formation. Through a large number of field investigations, the author re-determined the stratigraphic sequence and distribution of the Daqingshan Formation in the area and the nature of the contact with the underlying strata, and proposed that the Daqingshan Formation in the Upper Jurassic Daqingshan area is a Under the conditions of arid and hot climates, the lacustrine facies sedimentation and bio-depletion are strictly controlled by the dams of Dam-Jimawan-Jinduan Dian and are unconformable with the underlying strata. Division, contrast and the history of geological evolution is of great significance.