辽宁兴城地区长城系团山子组与大红峪组不整合接触特征及其对兴城运动的意义

Unconformity between Tuanshanzi and Dahongyu formations of Changcheng Group in Xingcheng,Liaoning Province and its significance for Xingcheng Movement

通过野外地质调查,确定了辽宁兴城地区长城系大红峪组与下伏团山子组为角度不整合接触。夹山地区团山子组三段叠层石白云岩顶部发育有古喀斯特地貌,大红峪组下部有底砾岩。接触面可见大红峪组砾岩沿溶洞、解理缝或构造裂隙灌入团山子组白云岩中。地球化学分析结果表明,团山子组为氧化沉积环境,气候温暖湿润。而大红峪组为贫氧--氧化沉积环境,气候与团山子组比较变得炎热干燥。由此表明,兴城运动的存在具有合理性,并且对于兴城地区具有较大的影响作用。

Through field geological investigation,it is determined that the unconformity contact between Tuanshanzi and Dahongyu formations of Changcheng Group in Xingcheng,Liaoning Province.In Jiashan,the top of stromatolite dolostone in the 3rd Member of Tuanshanzi Formation develops the ancient karst landform while there are basal conglomerates in the bottom of Dahongyu Formation.On the contact surface,we can see the conglomerates of Dahongyu Formation are filling in the dolomite of Tuanshanzi Formation along the Karst cave,cleavage crack or structural fractures.The geochemical analysis results show that the sedimentation environment of Tuanshanzi Formation is oxidizing and the paleo climate is warm and wet.But the sedimentary environment of Dahongyu Formation is lean oxygen to oxidation,the paleo climate is hot and dry.The results above can prove that it is reasonable for the existence of Xingcheng movement which has a great influence on Xingcheng area.