新疆博格达麻沟梁地区晚石炭世祁家沟组地质特征及沉积相分析

The Geological Characteristics and Sedimentary Facies Analysis of Later Carboniferous Epoch Qijiagou Formation in Magouliang Area of Bogeda Mountain,Xinjiang

新疆博格达地区晚古生代处于弧后裂陷盆地,晚石炭世祁家沟组多被认为是滨海-浅海沉积环境。据前人沉积相研究成果分析,博格达弧后裂陷盆地东、西段开裂程度不同,因此处于博格达东、西段相变地区沉积相的研究显得尤为重要。本次在1∶5万地质调查基础上,通过对区内麻沟梁地区祁家沟组岩石组合、沉积构造及粒度样品分析,推断祁家沟组由扇三角洲、滨海、浅海相组成,扇三角洲相粗碎屑岩一定程度上为构造应力的突变产物,该认识为晚石炭世中晚期沉积盆地充填及构造演化奠定了沉积学基础。

Bogeda is in the back-arc rift basin in late Paleozoic,Qijiagou Formation was widely identified as the coastneritic deposit environmen in the later carboniferous epoch.According to the research results of predecessor for sedimentary facies,the craze degree of the eastern and western section of Bogeda in the back-arc basin is different,therefore the research of sedimentary facies is particularly important in the switch region between eastern and western section of Bogeda.On the basis of 1:50000 geological survey,through rock association,sedimentary structure and granularity analysis,sample research of the area for the Qijiagou formation,it suggests the formation consists of fan delta,littoral and shallow sea facies,and in a certain extent,the fan delta facies coarse clastic rocks belongs to Mutations product of tectonic stress,it lays the basis of sedimentology for the filling and tectonic evolution of the sedimentary basin in Late Carboniferous epoch in Bogeda.