桂中坳陷泥盆系沉积相及岩相古地理研究

发布时间：2018-01-11 14:25

本文关键词：桂中坳陷泥盆系沉积相及岩相古地理研究　出处：《长江大学》2015年硕士论文　论文类型：学位论文

【摘要】：桂中坳陷位于广西壮族自治区中部,其地理坐标约为东经107°30′-110°30′,北纬23°00′-25°00’之间。大地构造位置处于扬子准地台与华南褶皱带的结合部,其北倚雪峰山隆起,西以紫云—罗甸—都安断裂与罗甸断坳相邻,南、东则以凭祥—大黎、龙胜—永福断裂与大瑶山隆起和桂林坳陷过渡。晚古生代至三叠纪,沉积盆地是形成在加里东褶皱基底之上的大陆边缘拉张型盆地,早泥盆世晚期到早石炭世的陆内扩张,形成了桂中坳陷台地、台盆相间的被动大陆边缘盆地格局。多年的基础地质研究和油气勘探实践过程中,在桂中地区发现有大量的地表油气苗、沥青,在已完成的钻探井中发现存在着丰富的油气显示和大量的沥青层段。表明了桂中地区内沉积有机质丰富,原始生油条件优越,并发生过大量的油气生成、运移、聚集与成藏过程。具有广阔的油气勘探前景,是中国南方最具潜力的含油气盆地之一论文选取横县六景、黎塘—贵港剖面,东缘北流、象州剖面,东北缘桂林剖面、西缘南丹罗富剖面等进行系统研究,共实测或观测露头剖面16条,累计剖面长8000余米。结合前人的研究成果,展开了泥盆系的区域地层对比,按不同相区的岩性组合特征将桂中坳陷泥盆系地层划分为9个组,从老到新依次为莲花山组、那高岭组、郁江组、上伦组、大乐组、唐家湾组、桂林组、东村组、额头村组。建立起了桂中坳陷泥盆系地层的综合柱状图,地层的累计厚度2691m。桂中坳陷泥盆系地层主要出露于坳陷周边地区,是一套以海相碳酸盐岩为主的连续沉积地层,岩性主要为生物灰岩、生物屑灰岩、泥晶—粉晶灰岩、含泥或泥灰岩、礁灰岩、白云质灰岩、灰质白云岩和白云岩；局部见有砂岩、含砾砂岩、粉砂岩、泥质页岩、泥质灰岩、泥灰岩及硅质岩等碎屑岩沉积。碳酸盐岩沉积构造较少,主要有叠层状构造、示顶底构造、晶洞和栉状构造、花斑和纹层状构造、块状层理、水平层理等。桂中坳陷泥盆系碳酸盐岩灰岩中,生物及生物屑极为发育,包括了：层孔虫类、四射珊瑚类、横板珊瑚类、腕足类和兰绿藻等。它们在沉积学分析中具双重意义,首先,它们作为颗粒,通过形态、大小、分选、圆度等结构特征反映沉积环境的水动力条件。同时,它们作为生物,通过其丰度、分异性、生态、保存状态等反映生物的生活环境。因此具有特别重要的指示环境意义。以岩石学特征和生物学特征为沉积相的识别标志进行沉积体系与沉积相分析,这些标志主要为岩石的颜色、岩石层厚和形态、岩石结构组分和结构类型、沉积构造、岩石类型、生物的组分及丰度、生物的分异性、生物的组合、生物的保存状态等。桂中坳陷泥盆系沉积建造包括了底部洛赫考夫阶—布拉格阶的碎屑岩建造和埃姆斯阶—法门阶的碳酸盐岩建造。其中碳酸盐岩沉积主要是碳酸盐潮坪—台地—生物丘—台间裂陷盆地体系。台地与断陷盆地之间有台地边缘生物丘、台地前缘斜坡。斜坡之外为深水盆地沉积。可以划分为台地、台地边缘、陆棚—台沟三个相区,并识出潮坪相、局限台地相、开放台地相、生物礁丘、藻礁相、台地前缘斜坡相、陆棚相、台沟相等9个沉积相带。
[Abstract]:Located in central the Guangxi Zhuang Autonomous Region in Guizhong depression, about the geographical coordinates of longitude 107 degrees 30 degrees between '-110 30', 00 '-25 degrees north latitude and 23 degrees 00'. Tectonically located in the junction of Yangtze metaplatform and Southern China fold belt, the North West to the Ziyun Xuefeng uplift, Luodian Du'an fault and the Luodian fault depression adjacent to south, east to Pingxiang, Lebanon, Longsheng, Yongfu fault and transition in Dayaoshan uplift and depression of Guilin. Late Paleozoic to Triassic, sedimentary basin is a continental margin on the Caledonian fold basement extensional basin, late Early Devonian to Early Carboniferous intracontinental expansion the formation of the platform, in Guizhong depression, the pattern of the passive continental margin basin and basin. Geology study and practice of oil and gas exploration process for many years, there are a large number of surface oil and gas were discovered in the middle area of Guangxi asphalt, found in drilling wells have been completed in the There are abundant oil and gas shows and a large number of asphalt layers. That the Guangxi area of sedimentary organic matter abundance, the original source conditions, and had a large number of oil and gas generation, migration, accumulation and accumulation process. Wide oil and gas exploration prospects, is one of the most potential petroliferous basin the paper selects Hengxian six Chinese South King, Litang - Guigang section, the eastern margin of the north, Xiangzhou section, Northeastern Guilin section, systematic research on the western margin of the Nandan Luo section, were measured or observed outcrop section 16, the cumulative profile of more than 8000 meters long. Combined with previous research results, the regional stratigraphic correlation the Devonian, according to lithologic characteristics in different facies of the Devonian in Guizhong depression strata are divided into 9 groups, from the old to the new order of Lotus Hill group, the kaolin group, the group, shanglun group, music group, tangjiewan group, Guilin group, village group, village head Group. Established a comprehensive column of Devonian in Guizhong depression, major depression exposed in the surrounding areas of the Devonian strata in the total thickness of Guangxi 2691m. in depression, which is a set of marine carbonate rocks of the continuous sedimentary strata, lithology is mainly biogenic limestone, bioclastic limestone. Micritic limestone - powder, mud or limestone, reef limestone, dolomitic limestone, calcite dolomite and dolomite; see local sandstone, pebbly sandstone, siltstone, shale, argillaceous limestone, marl and siliceous rocks of clastic sedimentary carbonate sedimentary structure. Made less, there are laminated structures, geopetal structures, and geode ctenoid structure, and a laminated structure, massive bedding, horizontal bedding. Devonian in Guizhong depression carbonate in limestone, biological and biological chip is very well developed, including: stromatopora, rugose coral class Tabulata, brachiopods, and Blue green algae. They have dual significance in sedimentology analysis firstly, through them as particles, morphology, size, sorting, roundness and other structure reflects the characteristics of hydrodynamic conditions of the sedimentary environment. At the same time, as the creature, through its abundance, diversity, ecological preservation status reflect biological living environment. Therefore with indicating environmental significance particularly important. The petrological characteristics and biological characteristics to identify markers of sedimentary facies sedimentary system and sedimentary facies analysis, these signs mainly rock color, rock thickness and morphology, rock components and structure types, sedimentary structures, rock types, composition and abundance of organisms, divided specific biological, biological, biological state of preservation. The construction includes the bottom Hekaofu order - Prague Luo order of clastic rock and Ames order - Famennian DEVONIAN SEDIMENTARY carbon in Guizhong depression Acid salt rock formation. The sedimentary carbonate is mainly carbonate tidal flat - platform - Taiwan - bioherm rift basin system. The platform edge bioherm basin between the platform and the fault, foreslope. The slopes for deep sedimentary basin. Can be divided into platform, platform edge, shelf - Taiwan ditch three a phase region, and identify the tidal flat facies, restricted platform facies, open platform facies, reef mounds, algal reef facies, foreslope facies, continental shelf facies, facies Taiwan ditch 9 equal deposition.

【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P531

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