广安龙门峡南剖面下三叠统嘉陵江组碳酸盐岩岩石学及成岩作用特征
发布时间：2018-10-07 19:05
【摘要】：龙门峡南剖面位于四川盆地东部,广安市东北的光辉乡境内,构造位置处于川东高陡构造带西侧,华蓥山帚状构造背斜的轴部,有连续的三叠系地层出露地表。本文选择龙门峡南剖面嘉陵江组为研究对象,采用野外观察与室内分析相结合的方法,以沉积岩石学、碳酸盐岩沉积学、岩相古地理等理论为指导,通过野外剖面的实测资料,综合运用薄片鉴定、阴极发光分析等技术手段,对研究区下三叠统嘉陵江组碳酸盐岩的岩石学特征及成岩作用进行了系统研究:查明岩石组分、组构及类型,并简述了岩石中的成岩作用类型。龙门峡南剖面嘉陵江组总厚度669.44m,比川东其他地区出露的嘉陵江组地层稍厚。结合野外剖面测量和室内薄片观察分析,按岩性把嘉陵江组分为四段,其中嘉一段厚度319.04m,以石灰岩为主;嘉二段厚70.13m,以白云岩和盐溶角砾岩为主;嘉三段厚196.86m,以石灰岩为主;嘉四段厚83.41m,以白云岩和盐溶角砾岩为主。在野外观察和室内薄片分析的基础上,将研究区下三叠统嘉陵江组的岩石类型划分为灰岩、白云岩和盐溶角砾岩三大类,并在此基础上细分为亮晶颗粒灰岩、微晶颗粒灰岩、颗粒微晶灰岩-含颗粒微晶灰岩、纹层状微晶灰岩、蠕虫状微晶灰岩、结晶灰岩、微晶白云岩、结晶白云岩等8个亚类。在岩石学特征的基础上,认为研究区嘉陵江期主要发育局限台地和蒸发台地两种沉积相。在漫长的地质历史中,嘉陵江组地层经历了复杂的成岩过程,成岩作用类型丰富,主要有泥晶化作用,压实、压溶作用,方解石胶结作用,白云石化作用,重结晶作用,破裂作用,溶解作用,硅化作用,去石膏化作用,以及黄铁矿、萤石、天青石等自生矿物的形成。在成岩过程的元素迁移方面,总体上表现为Sr的丢失和Mn、Fe的获取,大多数白云岩因具有相对较高的Mn含量而具有比石灰岩强的阴极发光性。
[Abstract]:The south section of Longmenxia is located in the eastern part of Sichuan basin and the territory of Guanghui Township in the northeast of Guangan City. The tectonic position is located in the west of the high-steep structural belt in eastern Sichuan and the axis of Huayingshan broom-like structural anticline with continuous Triassic strata appearing on the surface. In this paper, the Jialingjiang formation in the south section of Longmenxia is selected as the research object, the field observation and laboratory analysis are combined, and the theories of sedimentary petrology, carbonate sedimentology, lithofacies and paleogeography are taken as the guidance, and the field profile data are measured. The petrological characteristics and diagenesis of carbonate rocks of the Lower Triassic Jialingjiang formation in the study area were systematically studied by means of thin slice identification and catholuminescence analysis. The types of diagenesis in rocks are briefly described. The total thickness of Jialing River formation in the south section of Longmenxia is 669.44 m, which is a little thicker than that of Jialing River formation exposed from other areas in East Sichuan. The Jialing River formation is divided into four sections according to lithology, which is 319.04 m thick in Jia-1 member, 70.13 m thick in dolomite and salt-soluble breccia, 196.86 m in thickness in Jia-3 member, mainly limestone in Jia-1 formation, 70.13 m in thickness and 70.13 m in thickness in Jialingjiang formation. The thickness of Jiaxi formation is 83.41 m, mainly dolomite and salt solution breccia. On the basis of field observation and laboratory sheet analysis, the rock types of the Lower Triassic Jialingjiang formation in the study area are divided into three types: limestone, dolomite and salt-soluble breccia. On this basis, they are subdivided into bright grained limestone and microcrystalline granular limestone. Granular microcrystalline limestone-granular-bearing microcrystalline limestone, lamellar microcrystalline limestone, wormlike microcrystalline limestone, crystalline limestone, microcrystalline dolomite, crystalline dolomite, etc. On the basis of petrological characteristics, it is considered that two sedimentary facies, limited platform and evaporative platform, mainly developed in Jialing River period in the study area. In the long geological history, the formation of Jialingjiang formation has experienced complicated diagenesis process, and the diagenesis is rich in types, such as mud crystallization, compaction, pressure-dissolution, calcite cementation, dolomitization, recrystallization, etc. Rupture, dissolution, silicification, degypsum, and the formation of pyrite, fluorite, celadite and other authigenic minerals. In the aspect of element migration in diagenetic process, the loss of Sr and the acquisition of Mn,Fe are the main manifestations. Most dolomite has stronger cathodic luminescence than limestone because of its relatively high Mn content.
【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
本文编号：2255334
[Abstract]:The south section of Longmenxia is located in the eastern part of Sichuan basin and the territory of Guanghui Township in the northeast of Guangan City. The tectonic position is located in the west of the high-steep structural belt in eastern Sichuan and the axis of Huayingshan broom-like structural anticline with continuous Triassic strata appearing on the surface. In this paper, the Jialingjiang formation in the south section of Longmenxia is selected as the research object, the field observation and laboratory analysis are combined, and the theories of sedimentary petrology, carbonate sedimentology, lithofacies and paleogeography are taken as the guidance, and the field profile data are measured. The petrological characteristics and diagenesis of carbonate rocks of the Lower Triassic Jialingjiang formation in the study area were systematically studied by means of thin slice identification and catholuminescence analysis. The types of diagenesis in rocks are briefly described. The total thickness of Jialing River formation in the south section of Longmenxia is 669.44 m, which is a little thicker than that of Jialing River formation exposed from other areas in East Sichuan. The Jialing River formation is divided into four sections according to lithology, which is 319.04 m thick in Jia-1 member, 70.13 m thick in dolomite and salt-soluble breccia, 196.86 m in thickness in Jia-3 member, mainly limestone in Jia-1 formation, 70.13 m in thickness and 70.13 m in thickness in Jialingjiang formation. The thickness of Jiaxi formation is 83.41 m, mainly dolomite and salt solution breccia. On the basis of field observation and laboratory sheet analysis, the rock types of the Lower Triassic Jialingjiang formation in the study area are divided into three types: limestone, dolomite and salt-soluble breccia. On this basis, they are subdivided into bright grained limestone and microcrystalline granular limestone. Granular microcrystalline limestone-granular-bearing microcrystalline limestone, lamellar microcrystalline limestone, wormlike microcrystalline limestone, crystalline limestone, microcrystalline dolomite, crystalline dolomite, etc. On the basis of petrological characteristics, it is considered that two sedimentary facies, limited platform and evaporative platform, mainly developed in Jialing River period in the study area. In the long geological history, the formation of Jialingjiang formation has experienced complicated diagenesis process, and the diagenesis is rich in types, such as mud crystallization, compaction, pressure-dissolution, calcite cementation, dolomitization, recrystallization, etc. Rupture, dissolution, silicification, degypsum, and the formation of pyrite, fluorite, celadite and other authigenic minerals. In the aspect of element migration in diagenetic process, the loss of Sr and the acquisition of Mn,Fe are the main manifestations. Most dolomite has stronger cathodic luminescence than limestone because of its relatively high Mn content.
【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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