四川桥亭下三叠统飞仙关组岩石学特征及成岩作用

发布时间：2018-07-16 23:10

【摘要】：下三叠统飞仙关组是四川盆地资源量最大的层系之一。前人陆续在川东北飞仙关组鲕粒滩发现了普光、罗家寨、铁山坡和渡口河等大中气田群。这些气田主要分布在开江-梁平海槽的南缘,对开江-梁平海槽北缘地区研究较少。本论文选择位于开江-梁平海槽北缘的南江桥亭剖面,通过实测野外剖面、野外描述以及样品采集等室外工作,结合室内显微观察、阴极发光、扫描电镜等微观研究方法,以碳酸盐沉积学、古生物学与成岩作用等相关理论为基础,对桥亭剖面飞仙关组岩石学特征以及成岩作用等方面进行系统研究。在野外,根据地层的岩性、结构、构造及产状等特征,判断出飞仙关组的顶、底界线,并划分出飞一段~飞四段。飞一段和飞三段以青灰色-浅灰色碳酸盐岩为主,飞二段和飞四段以紫红色泥质含量较高的泥灰岩和灰泥岩为主。该剖面下三叠统飞仙关组碳酸盐岩主要由碳酸盐矿物、自生的非碳酸盐矿物和陆源碎屑矿物组成。碳酸盐矿物主要是方解石和白云石;自生非碳酸盐矿物主要为自生石英、黄铁矿、天青石;陆源碎屑矿物多为石英和长石。研究剖面的岩石类型划分为灰岩、白云岩和泥质岩三大类,并在此基础上细分为颗粒灰岩、颗粒微晶灰岩、微晶灰岩、微晶白云岩、颗粒白云岩、灰质泥岩等亚类。根据一些特殊的岩石组构以及沉积相特征,认为研究剖面飞仙关地层经历了海水潜流环境、淡水潜流环境、淡水渗流环境、埋藏环境和表生成岩环境。主要经历的成岩作用有:泥晶化作用、胶结作用、溶蚀作用、重结晶作用、压实-压溶作用、破裂与充填作用、自生黄铁矿以及硅化作用等,并论述了沉积物的成岩演化序列。
[Abstract]:The Feixianguan formation of the Lower Triassic is one of the most abundant strata in Sichuan Basin. The oolitic beach of the Feixianguan formation in northeastern Sichuan has been discovered in succession, such as Puguang, Luojiazhai, Tieshan and Dukouhe gas fields. These gas fields are mainly distributed in the southern margin of the Kaijiang-Liangping trough, but few studies have been done on the northern margin of the Kaijiang-Liangping trough. In this paper, the Nanjiangqiao Pavilion section, located in the northern margin of the Kaijiang-Liangping trough, is selected. Through the outdoor work such as field profile, field description and sample collection, combined with indoor microscopic observation, cathodoluminescence, scanning electron microscope and other micro-research methods, Based on the theories of carbonate sedimentology, paleontology and diagenesis, the petrological characteristics and diagenesis of the Feixianguan formation in Qiaoting section were systematically studied. In the field, according to the lithology, structure, structure and occurrence of the strata, the top and bottom boundaries of the Feixianguan formation are determined, and the Fei-1 ~ Fei4 sections are divided. The main carbonate rocks in the first and third members of Feifei are grey-gray-grayish carbonate rocks, and the marl and lime-mudstone with high content of purplish red mudstone are the main ones in the second and fourth member of Feifei. The carbonate rocks of the Feixianguan formation in the lower Triassic are mainly composed of carbonate minerals, authigenic non-carbonate minerals and continental clastic minerals. The carbonate minerals are mainly calcite and dolomite, the authigenic non-carbonate minerals are mainly authigenic quartz, pyrite and celadite, and the continental clastic minerals are mostly quartz and feldspar. The rock types of the study section are divided into three types: limestone, dolomite and argillaceous rock. On this basis, they are subdivided into granular limestone, granular microcrystalline limestone, microcrystalline dolomite, granular dolomite and lime-mudstone. According to some special rock fabric and sedimentary facies characteristics, it is considered that the Feixianguan strata in the study section have experienced sea water subcurrent environment, fresh water seepage environment, burial environment and epigenetic rock environment. The main diagenesis include mud crystallization, cementation, dissolution, recrystallization, compact-pressure solution, rupture and filling, authigenic pyrite and silicification, etc. The diagenetic evolution sequence of sediments is discussed.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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