青海冷湖地区古近系新近系沉积相、沉积环境类型及演化

发布时间：2018-07-13 08:04

【摘要】：青海冷湖研究区是柴达木盆地的重要组成部分,有着良好的油气勘探前景。本论文通过对青海省冷湖镇相关区域进行地质学方法研究,在前人研究成果的基础上结合剖面、粒度分析、孢粉特征等资料对冷湖地区的岩石学特征、地层特征、沉积构造特征进行分析,总结其沉积相的类型及其演化特征。通过地层剖面的岩性观察总结,采用岩石地层的划分方法将研究区古近系—新近系各组地层进行确定,代替了前人经常使用的古生物区分地层的方法。通过对研究区各组地层的孢粉特征进行分析可以得出研究区在古近系—新近系的气候变化主要为气温逐渐下降转为寒冷。气候呈干燥—湿润—干燥的变化特征。通过对研究区内的岩石学特征、沉积构造、概率曲线特征等标志进行分析,大体确定了研究区内部的沉积相类型:包括冲击扇相、河流相、湖泊相、扇三角洲相、等沉积相类型。并对相应的沉积相类型进行了划分,其中冲积扇相可以划分为扇根、扇中、扇端三个亚相,辫状河亚相可以分为河道和心滩两个微相。扇三角洲可以分为扇三角洲平原、扇三角洲前缘两个亚相。湖泊相可以分为滨湖、浅湖、深湖—半深湖三个亚相。就各沉积相在研究区内所占的比例而言,其中湖泊相分布最为广泛,河流相次之。通过对冷湖镇工作区的1:5万地质填图的研究成果并结合前人的钻井资料对该研究区古近系—新近系各组地层进行剖面对比,并作出各组的地层对比图,通过地层对比图并结合前人资料总结出沉积相的变化类型,画出沉积相展布图以及总结出研究区的相模式。最后通过对研究区的沉积相柱状图进行分析,确定了研究区在第三系主要有5次水位的涨落过程。
[Abstract]:The cold lake research area in Qinghai is an important part of the Qaidam Basin and has a good prospect for oil and gas exploration. In this paper, the geological characteristics and characteristics of the Cold Lake area are combined on the basis of the research results of the related regions of Cold Lake Town in Qinghai province. The characteristics of sedimentary structure are analyzed, and the types and evolution characteristics of the sedimentary facies are summarized. Through the lithologic observation of the stratigraphic section, the stratigraphy of the Paleogene Neogene in the study area is determined by the method of lithostratigraphy division. The analysis of the characteristics of the sporopollen can be drawn that the climate change in the Paleogene Neogene is mainly characterized by the change of the temperature gradually to the cold. The climate is dry, moist and dry. Through the analysis of the petrological characteristics, the sedimentary structure and the characteristics of the probability curve in the study area, the interior of the study area is generally determined inside the study area. The types of sedimentary facies include the impact fan facies, fluvial facies, lacustrine facies, fan delta facies and other sedimentary facies types, and the corresponding sedimentary facies types are divided. The alluvial fan facies can be divided into fan root, fan and fan end three subfacies, braided river subfacies can be divided into two microfacies of river channel and heart beach. Fan delta can be divided into fan delta flat. The lacustrine facies can be divided into two subfacies of the fan delta front. The lake facies can be divided into three subfacies of Binhu, shallow lake, deep lake and half deep lake. In terms of the proportion of the sedimentary facies in the study area, the lake facies is the most widely distributed and the river phase is the next. Through the research results of the 1:5 ten million geological mapping in the cold lake town working area and the previous drilling data, The stratigraphic comparison of each group of the Paleogene and Neogene in this study area is compared, and the stratigraphic contrast diagram of each group is made. The variation types of the sedimentary facies are summed up by the stratigraphic contrast map and the previous data. The sedimentary facies map and the phase pattern of the study area are drawn. Finally, the sedimentary facies histogram of the study area is analyzed and determined. There are mainly 5 water level fluctuations in the third systems in the study area.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P534.6

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