湘西李梅矿田清虚洞组含矿层的构造沉积岩相特征研究

发布时间：2018-04-22 10:18

本文选题：湘西李梅 + 清虚洞组　；参考：《长安大学》2015年硕士论文

【摘要】：湘西-鄂西成矿带位于扬子地台与南华活动带过渡区,是我国16个重要成矿带之一。现已查明湘西北铅锌矿产于寒武系清虚洞组,含矿地层是重要的找矿目标。“湘西李梅矿田清虚洞组含矿层的构造沉积岩相特征研究”作为学位论文选题,具有重要的研究意义和找矿价值。本文依托“湘西张家界花垣整装勘查区矿田地质研究和找矿”地调项目,通过翔实的野外地质调查,取得剖面测量、构造路线观测、钻孔编录、采样分析等大量实际资料,进一步结合前人的成果资料开展综合分析,按时完成学位论文。在李梅矿田清虚洞期构造沉积岩相古地理、成矿构造和成矿规律等方面研究取得以下主要成果:1.详细编制了湘西李梅矿田清虚洞期岩相古地理图,深化了沉积相展布特点及构造演变成矿的认识。根据实测剖面,利用单因素分析多因素综合作图,显示清虚洞期沉积岩相由北西至南东依次为:局限台地相、藻灰岩相、浅水陆棚相。清虚洞组沉积盆地分布受NE-NNE方向构造控制。沉积相属于枢纽带碳酸盐岩体系,显示滩-礁-滩沉积相特征。铅锌矿床均分布于藻灰岩相。在富矿体集中地段,藻灰岩的厚度一般都大于100m。2.提出研究区两期成岩成矿构造,1)较早期的NW-SE向挤压应力场,形成了李梅、太阳山等NE-NNE向褶皱构造和麻栗场逆冲断裂带等构造。该期构造活动形成了主要的导矿、容矿和储矿构造。2)晚期的NE-SW向挤压剪切应力场,控制了成岩成矿期同生断层花垣-张家界大断裂,形成先左行挤压逆冲,后期右行张裂下滑的活动。使该走滑正断裂带对赋矿层位构成了一定的破坏。3.矿床主要是受各类断裂裂隙和藻灰岩相地层控制。清虚洞组早期构造控制了碳酸盐岩体系的滩-礁-滩相枢纽带沉积,使成岩期及其地层褶皱弯曲,藻礁灰岩相、浅滩相岩石的孔隙和裂隙成为主要的容矿空间,清虚洞组晚期构造有一定变化,继续发育层间角砾岩化和碳酸盐化,这使的含矿热液在裂隙和孔隙空间叠加聚集成矿。4.根据清虚洞组岩相分布和花垣-茶洞同生断裂的认识开展成矿预测:杨家寨和大脑坡深部隐伏矿层被钻孔揭露,证实清虚洞组含矿藻灰岩相呈NE-NNE向展布,且跨过花垣-茶洞大断裂。断裂北侧600米深部见矿,南侧100米深部见矿,说明花垣-张家界断裂正断层活动上盘北部岩块下滑500米,花垣-茶洞断裂带并非矿田的北边界,断裂带北侧具有较大的找矿前景,是下一步工作的优选靶区。
[Abstract]:Xiangxi-western Hubei metallogenic belt is one of 16 important metallogenic belts in China, which is located in the transitional area between Yangtze platform and South China active belt. It has been found that the lead-zinc deposits in northwest Hunan are in the Cambrian Qingxuodong formation and the ore-bearing strata are the important prospecting targets. The study on the structural sedimentary facies of the ore-bearing strata of Qingxuodong formation in Li Mei Orefield in Western Hunan Province is of great significance and prospecting value as the subject of the dissertation. This paper relies on the geological research and prospecting project of "the complete Orefield Geological Research and Prospecting in Huayuan, Zhangjiajie, Western Hunan Province," and obtains a large number of practical data, such as section survey, structural route observation, borehole cataloguing, sampling and analysis, through detailed field geological surveys. Further combined with the results of previous comprehensive analysis, on time to complete the thesis. In the study of sedimentary lithofacies paleogeography, metallogenic structure and metallogenic regularity of Qingxuodong period in Li Mei ore field, the following main achievements have been obtained: 1. The lithofacies paleogeography map of Qingxuodong period in Li Mei ore field in western Hunan is compiled in detail, which deepens the characteristics of sedimentary facies distribution and the understanding of tectonic evolution. According to the measured profiles and by using single factor analysis and multifactor comprehensive mapping, it is shown that the sedimentary lithofacies of Qingxuodong period are: limited platform facies, algal limestone facies and shallow shelf facies. The sequence of sedimentary lithofacies from north to west to south to east is: limited platform facies, algal limestone facies and shallow shelf facies. The distribution of sedimentary basins in Qingxuodong formation is controlled by the NE-NNE direction. The sedimentary facies belong to the carbonate rock system of the junction zone, showing the characteristics of the beach-reef-beach sedimentary facies. All lead-zinc deposits are distributed in algal limestone facies. In the concentrated area of ore-rich bodies, the thickness of algal limestone is generally greater than 100 m. 2. It is suggested that the early NW-SE compressive stress field in the two stages of diagenetic and metallogenic structure in the study area formed Li Mei, Sun Mountain and other NE-NNE fold structures, and the Mashichang thrust fault zone and so on. During this period, the main ore-conducting, ore-bearing and ore-storage tectonics formed NE-SW compressional shear stress field in the late stage, which controlled the large fault of Huayuan-Zhangjiajie in the diagenetic and metallogenic period, and formed the first left compressional thrust. Late right row tension glide activity. The strike-slip normal fault zone caused a certain damage to the ore-bearing horizon. The deposit is mainly controlled by various fracture fissures and algal limestone facies strata. The early tectonics of Qingxuodong formation controlled the deposit of the beach, reef and beach facies junction zone of carbonate system, which made the diagenetic period and its stratum fold bend, the pore and fissure of algal reef limestone facies and shoal facies rock become the main ore-bearing space. The late tectonics of Qingxuodong formation have some changes and continue to develop interlaminar breccia and carbonization, which results in the superposition and accumulation of ore-bearing hydrothermal fluid in the fissure and pore space to form ore .4. According to the lithofacies distribution of Qingxuodong formation and the understanding of Huayuan-Chadong syngenic faults, the metallogenic prediction is carried out: the buried strata in Yangjiazhai and the deep slope of the cerebrum are exposed by drilling, it is proved that the facies of algal limestone in Qingxuodong formation is distributed in NE-NNE direction. And across the Huaguan-tea hole rupture. The 600 meters deep ore deposits in the north side of the fault and the 100 meters deep ore deposits in the south side show that the Huayuanyan-Zhangjiajie fault normal fault block in the northern part of the upper block slid 500 meters, and the Huayuan-Chadong fault zone is not the northern boundary of the ore field. The north side of the fault zone has a great prospect of prospecting, which is the best target area for further work.
【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】：P613

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