广西南丹大厂地区泥盆纪地层地质特征

【作者】 李晓；

【导师】 燕永锋； 秦德先；

【作者基本信息】 昆明理工大学 ， 地质工程， 2010， 硕士

【摘要】 广西南丹大厂地区是举世闻名的超大型锡多金属矿床,对国内锡产业影响重大。矿区内地质条件复杂,成矿条件较好,因此吸引了国内外众多的地质研究者在该区进行研究作业。大厂矿床成因众说纷纭,陈毓川院士等对大厂矿田成矿规律进行了研究,建立了大厂锡多金属矿带矿床成矿系列和成矿模式；李锡林、叶绪孙等讨论了原生锡矿床的地质特征和成矿规律,论证了花岗岩及其成矿演化是锡多金属矿床形成的主要控制因素；蔡宏渊、雷良奇、周怀阳、张国林、韩发、廖宗廷、秦德先等提出了大厂锡多金属矿床同生火山喷气和后期与花岗岩有关热液叠加成矿的认识。这些研究主要侧重于花岗岩和矿床地质研究,尚未对地层进行过系统研究。本文结合“广西大厂锡矿泥盆纪地层控矿规律与成矿预研究”和“广西大厂铜坑矿东岩墙以东成矿规律及矿山增储研究”项目,在前人研究成果的基础之上,对该地区地层特征、岩石学特征、岩石地球化学及岩相古地理进行研究和探讨,初步查明了该地区主要地层的沉积特征与沉积环境变化。广西南丹大厂地区位于丹池褶皱带上,该区的矿产资源较丰富,地质特征复杂。长久以来,研究者们把对本区研究的重点放在岩浆岩、侵入岩上,对地层的研究比较少。本文以对地层的研究为切入点,结合研究过程中的新发现重新纠正了地层的划分方案。主要的成果包括以下几个方面：(1)对钻孔岩心样品、坑道块样的化验后,总结出大厂地区比较系统的地层划分方案。本次划分工作重点包括以下几个方面：根据泥盆纪溜江组硅质岩的产出特点,将其划分为三层；通过鉴定泥盆系中统罗富组样品,重新进行了划分；对泥盆系中统的矽卡岩进行了系统的研究；根据已有的各方面资料做出泥盆系柱状图。(2)在泥盆系中上统发现了基性、中性火山岩,并在“东岩墙”附近发现了次玄武岩脉。火山岩以玄武岩、蚀变安山玄武岩、凝灰岩为主；次玄武岩脉南北向产出,与“东岩墙”平行产出。(3)通过对研究区地层及侵入岩中样品分析,并得出各个地质时期常量元素、微量元素及稀土元素地球化学特征。做出各元素在垂向上的变化曲线,结合各个时期的沉积特征进行比较。(4)通过各个地层岩性及产出的研究,结合前人的理论经验,对大厂区泥盆系各统古地理相做出总结。(5)提出“东岩墙”应为泥盆纪同生沉积断裂构造,海西早期显张性,为同沉积(同生)断裂,控制了地层的沉积及成矿作用；印支-燕山期北西向褶皱作用,显压扭性,控制了泥盆纪地层的侵入活动及叠加改造成矿作用。(6)提出广西大厂锡矿的“东岩墙”控矿模式,并在研究区划分出具有找矿远景的靶区。更多还原

【Abstract】 Dachang of Guangxi nandan is a world-famous super tin polymetallic deposit in China. Also the tin industry has a great influence to the world. The complex geological conditions and the metallogenic conditions attracted numerous geological researchers studying in the region. There is so many statment of the DaChang metallogeny. Yu-Chuan Chen academicians mines and fields by studying the pattern forming, and established Dachang tin-polymetallic ore belt metallogenic series and metallogenic model. Xilin Li, Xu-Sun Ye, etc. discussed the primary tin ore deposit, the geological characteristics and the metallogeny, demonstrating the granite and metallogenic evolution is the formation of tin-polymetallic deposits in the major controlling factors. Cai Hongyuan, Liang-qi Lei, Huai-yang Zhou, Guo-Lin Zhang, Hanfa, Zong-Ting Liao, De-Xian Qin, etc. belive that it’s a syngenetic mineral deposit with volcanic blowpiping and related to Granite hydrothermal then. These studies focused primarily on geological studies of granite and mineral deposits, has not yet been systematic research on the formation.This paper combined to "The study of Dachang Devonian controlling tin ore’s mineralization" and "The east of Dachang east rock wall’s metallogenic regularity and prediction" project, on the basis of the previous research results, the writer Researched and explorationed the stratigraphy, rock characteristics, rock geochemistry and rock facies and palaeogeography in the area.The researcharea stayed in Danchi fold belt.It is affluent in minerals,but geological features is very complex. For a long time, researchers focus on igneous rocks, intrusive rocks.So the formation’s analyse is trifle. As a pointcut,we made new division of the formation combined with the new discovery during research process. Main accomplishments include the following:(1) After drilling core samples and testing the tunnel plots, we summed up a more systematic stratigraphic division of Dachang district. This division mainly focuses on the following:According to the Devonian Period slide River Group chert output characteristics, it is divided into three layers; through the identification of the Devonian Period in the Unification Luo group of samples,they have been re-classified; The skarn is carried out a systematic study on Devonian; we make histograms on the basis of the information on various aspects of Devonian.(2) In the middle and upper Devonian Commission found basic, neutral volcanic rock, and the sub-basalt veins was found near the "East Rock Wall". Volcanic basalt, altered andesitic basalt, tuff-based; times basalt pulse outputs from north to south, and parallel with the "east rock wall" outputs.(3) Through the study sample of stratigraphy and intrusive rocks in the area, reach the geochemistry feature about constant element, trace elements and REE of various geological periods. Made on the vertical curves of the various elements, combined with the sedimentary characteristics of each period for comparison.(4) through the various studies of Lithology and output, combined with the theory of our predecessors experience, given Summary to palaeogeography phase of Devonian of integration of Dachang District.(5) Proposed the "east rock wall" should be the same as the Devonian sedimentary faults, substantially isotonic in the early Hercynian, for the same deposition (with students) fault, controlling the formation of the deposition and mineralization; Indo-Yanshanian north-west to the folding,Hin-twisting pressure, controlling the transformation of invasive activity and superimposed mineralization in the Devonian strata.(6) Proposed the "East Rock Wall" ore-controlling mode of Dachang tin, and Carved out the target areas with prospecting potential in the research division.更多还原