四川盆地早寒武世龙王庙期岩相古地理

发布时间：2018-05-07 04:19

本文选题：古地理格局 + 颗粒滩　；参考：《西南石油大学》2015年硕士论文

【摘要】：本文以岩石地层学、生物地层学、碳酸盐岩岩石学、碳酸盐岩沉积学和碳酸盐岩储层地质学为指导,基于四川盆地盆内及其周缘171份钻孔取心和露头剖面资料,在前人相关研究的基础上对早寒武世龙王庙期地层进行岩相古地理相关研究。在区域地质背景分析的基础上,通过野外露头、测录井、岩心、薄片的综合分析,结合区域背景和龙王庙组地层充填厚度分析认为,四川盆地周缘北邻摩天岭微古陆和汉南古陆、西接康滇古陆,东南和东北分别为威信—黔江、石阡—秀山—龙山和镇巴—巫溪—巴东水下古隆起环抱；盆内呈近北东方向展布的川中古隆起和阆中—通江拗陷、江津—奉节拗陷构成“一隆两拗”,南部泸州—筠连—昭通继承性拗陷依然存在；盆地及周缘向东北隅和东南隅分别接入秦岭洋和江南盆地。根据岩石类型、沉积构造、沉积旋回、古生物类型、测井响应特征进行单井沉积相划分、连井沉积相对比,结果表明,受古地理背景影响,龙王庙期发育连陆碳酸盐岩台地—斜坡—盆地沉积体系,连陆碳酸盐岩台地构成沉积主体,可识别出混积潮坪、局限～蒸发台地、半局限～局限台地和台地边缘沉积相类型。在此基础上,结合碎屑岩含量与陆源方向、石灰岩、白云岩和膏盐岩含量与海域局限性和台地边缘相对位置、颗粒岩含量等单因素定量分析,恢复龙王庙期岩相古地理展布样式并建立沉积模式。结果表明盆内以发育局限～蒸发环境的云岩类和膏盐岩类沉积,盆地外围逐步向石灰岩沉积过渡为主,间夹白云岩沉积,水体具有逐渐开阔、盐度逐渐正常的趋势,绵阳—镇巴北所处的潮坪向海侧、乐山—开江所在的川中古隆起,威信—黔江、石阡—秀山—龙山和镇巴—巫溪—巴东水下古隆起、泸州—筠连—昭通拗陷周缘为台内颗粒滩有利发育区,东南缘石阡—思南—龙山—桑植和东北缘镇巴—兴山一带为颗粒滩潜在区域。中上扬子地区具有典型台地—陆表海沉积相模式,发育连陆碳酸盐岩台地—斜坡—盆地沉积体系,川中地区为局限～蒸发泻湖夹颗粒滩的局限～蒸发台地相,向东和南部过渡为半局限～局限泻湖夹颗粒滩相为主的半局限～局限台地相,东南部和东北部进入高能台缘带,向两个方向进一步发育半深海斜坡和深海盆地相。颗粒滩相储集性能优越,颗粒岩在大区内保持西浅东深、隆坳相间的古地理格局下,在古地貌高地具有广覆式“五线一带”的平面分布样式。受古隆起宽缓古海底底形控制,次一级海平面升降影响其横向连续性。
[Abstract]:Guided by lithostratigraphy, biostratigraphy, carbonate petrology, carbonate sedimentology and carbonate reservoir geology, this paper is based on 171 drilling coring and outcrop profiles in and around the basin of Sichuan Basin. Based on previous studies, the lithofacies and paleogeography of early Cambrian Longwangmiao strata were studied. Based on the analysis of regional geological background, through the comprehensive analysis of field outcrop, logging, core and slice, combined with the analysis of regional background and the formation filling thickness of Longwangmiao formation, it is concluded that, The margin of Sichuan Basin is bounded by the Tianjiling and Hannan ancient land to the north, KangDian to the west, Weixin to Qianjiang in the southeast and Qianjiang to the northeast, Shipathian-Xiushan-Longshan and Zhenba to Wuxi to the underwater paleouplift. In the basin, the central Sichuan uplift and Langzhong-Tongjiang depression are distributed in the north east direction, the Jiang Jin Fengjie depression constitutes "one uplift and two depressions", and the southern Luzhou-Junlian Zhaotong inherited depression still exists. The basin and its periphery are connected to the Qinling Ocean and the Jiangnan basin to the northeast and southeast, respectively. According to the rock types, sedimentary structures, sedimentary cycles, paleontological types and log response characteristics, single well sedimentary facies are divided, and the sedimentary facies of multiple wells are compared. The results show that they are influenced by paleogeographic background. In Longwangmiao period, the carbonate platform, slope and basin sedimentary system were developed, and the carbonate platform formed the main sedimentary body. The sedimentary facies types of mixed tidal flat, limited to evaporation platform, semi-limited to restricted platform and platform margin could be identified. On this basis, combined with the single factor quantitative analysis, such as clastic rock content and continental source direction, limestone, dolomite and gypsum salt content and the limitation of sea area and the relative position of platform edge, granulite content, etc. The distribution pattern of lithofacies and paleogeography in Longwangmiao period was restored and sedimentary model was established. The results show that the basin consists of dolomite and gypsum salt deposits with limited ~ evaporative environment, and the transition from the periphery of the basin to the limestone deposit is the main one, and the intercalated dolomite deposits, the water body is gradually open and the salinity is gradually normal. Mianyang-Zhenba north of the tidal flat to the sea side, Leshan-Kaijiang where the middle-ancient uplift of Sichuan, Weixin-Qianjiang, Shiqian-Xiushan-Longshan and Zhenba-Wuxi-Padong underwater ancient uplift, The margin of Luzhou-Junlian-Zhaotong depression is favorable for the development of grain beach in the platform, the area of Shipathian-Sinan-Longshan-Sangzhi in southeastern margin and the area of Zhenba to Xingshan in northeast margin are potential areas of grain beach. In the middle and upper Yangtze area, there is a typical platform-surface sea sedimentary facies model, and the carbonate rock platform-slope-basin sedimentary system is developed, and the central Sichuan area is a limited-evaporative lagoon grained beach limited to evaporative platform facies. The transition to the east and south is mainly semi-confined ~ confined lagoon grained beach facies. In the southeast and the northeast, the high-energy platform margin zone is entered, and the semi-deep sea slope and deep-sea basin facies are further developed in both directions. The granular-beach facies reservoir is superior, the granulite rock keeps the west shallow and the east deep in the big area, under the paleogeographic pattern of the interphase of the long depression, it has the plane distribution style of "five lines" in the paleogeomorphic highland. The horizontal continuity is affected by the subprimary sea level rise and fall controlled by the broad and gentle paleo-seabed bottom shape of the ancient uplift.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P531

【参考文献】