【作者】 姚正红；

【导师】 肖惠良；

【作者基本信息】 中国地质科学院 ， 地球化学， 2011， 硕士

【摘要】 南山花岗岩体位于广东省始兴县最有代表性的贵东复式岩体之北、陂头复式岩体西端,岩体所处的粤北地区是我国重要的钨、锡、钼、铅、锌多金属矿集中区。本学位论文以南山矿区钨钼多金属矿床及其赋矿岩石南山花岗岩为研究对象,通过赋矿花岗岩的同位素年代学、地球化学特征的研究,探讨其成岩机理,阐述其形成的构造环境,进而探索南山花岗岩体与钨锡多金属矿内在成因联系。南山矿区内出露大量的燕山期花岗岩,南山花岗岩锆石的SHRIMP U-Pb年龄为158.1±1.8Ma,岩性以细粒黑云母花岗岩、二云母二长花岗岩和中粒似斑状黑云母花岗岩为主,岩石地球化学特征显示,南山燕山期花岗岩以高硅、富碱、准铝-过铝、贫Ca和Mg以及高TFeO/MgO、低CaO/Na2O为特征,属于准铝-过铝质碱性岩石。微量元素特征显示富Zr、Y、U、Nb等高场强元素,贫Ba、Sr、Ti等元素,与铝质A型花岗岩地球化学特征相符,稀土配分图呈典型的A型花岗岩特有的海鸥型,Eu强烈亏损,表明岩浆发生过强烈的分异结晶作用。本学位论文认为,南山花岗岩归属于H型花岗岩,是在中晚侏罗世相对挤压和拉张转换背景下,由地壳的泥质岩和少量砂质岩受到幔源物质混染发生部分熔融上侵形成的。南山矿区钨锡多金属矿床为“多位一体”的复合矿床,矿化类型主要分为花岗岩型钨钼矿、矽卡岩型钨锡多金属矿和石英脉型钨铝矿三类。从空间分布看,“体中体”式燕山期花岗岩型钨铝多金属矿体主要受控于燕山期早期第二阶段第二次侵入和燕山早期第三阶段侵入的花岗岩中,矿体赋存在成矿花岗岩内及其与围岩接触带内带；石英脉型钨钼矿体往往产于岩体穹顶内外接触带,主要受控于花岗质岩浆侵位时产生的节理和裂隙,层控型矽卡岩型钨锡铋矿体赋存于氧化矽卡岩和石榴石透辉石矽卡岩中,矿体明显受岩体接触带控制,呈层状产出。矿区含矿花岗岩属高分异的H型花岗岩,成岩成矿年龄的一致亦表明成岩成矿的密切联系。综上所述,通过本次工作获得了南山钨锡多金属矿床与南山花岗岩体关系密切,南山花岗岩体为成矿提供了物质来源、热源和热液,是南山钨锡多金属矿床的成矿母岩。根据南山矿区花岗岩演化特征及矿床特征,本学位论文系统论证了南山地区燕山期花岗岩与南山钨锡多金属矿的成矿关系,认为成矿模式从上自下依次为矽卡岩型、石英脉型(受节理、裂隙带控制)和花岗岩型钨锡多金属矿体。更多还原

【Abstract】 The Nanshan granite pluton is located in the north of the Guidong composite granite pluton,a most representative granite pluton in Shixing county, north of Guangdong province, and in the south of the Beitou composite granite pluton. The north Guangdong area, where the Nanshan pluton is situated, is an mineralized area in China. This academic degree paper focuses the Nanshan tungsten-molybdenum polymetallic deposit and Nanshan granites as the host rocks of the deposit, to discuss lithogenesis mechanism and tectonic environment during the formation of the pluton, then to expounds the genetic relationship between Nanshan granite pluton and tungsten-tin polymetallic mineralization, based on the study of isotope age and geochemical characteristics of the host rocks.The Yanshanian granites are widely exposed in the Nanshan mineralized region. The Nanshan pluton mainly consists of fine-granied granites, two-mica monzogranites and middle porphyritic biotite granites. The SHRIMP zircon U-Pb age is 158.1±1.8Ma. The lithogeochemical features of Nanshan Yanshanian granites show that they exhibit high Si and alkali,strongly-peraluminous,low Ca and Mg,high TFeO/MgO and low CaO/Na2O, belonging to the aluminum alkaline granites. In trace element compositions, the granites are enriched in high strength field elements of Zr,Y,U,Nb, and depleted in Ba,Sr,Ti, indicative of a consistency with aluminum A-type granites. REE patterns are nearly horizontally V-shaped characteristic of A-type granites, with a stong depletion of Eu, indicating the magma experienced a strong crystallization differentation. Thus, the present study considers that the Nanshan granites are belongto H-type granites,which were formed by upwelling partial melting of the pelite and less clay-derived meet contaminated by the mantle-derived material in the condition of transition from relative compression to extenion.Nanshan tungsten-tin polymetallic deposit is a "multi-type" composite deposit. Mineralization types are mainly divided into three types,i.e. granite type tungsten-molybdenum,skarn type tin polymetallic and quartz vein type tungsten-molybdenum mineralizations. In terms of spatial distribution, granite type ore bodies are mainly controlled by the granites formed in the second intrusion and the third intrusion of the second phase of the Early Yanshanian movement,and occurred in the ore-forming granites and inner contact zone between ganites and their surrounding rocks;quartz vein type ore bodies are occurred in the inner contact and exocontact zones in the dome of the pluton, and controlled by joints and cracks produced during emplacement of the by granitic magma skarn type ore bodies are occurred in oxidized skarns and garnet-diopside skarns, which show a stratified occurrence,and obviously controlled by contact zone of the pluton.Ore-bearing granites in the Nanshan mineralized area belong to high differentational H-type granites. The consistency between lithogenesis age and metallogenic age also suggests a close relationship between lithogenesis and mineralization. To sum up, Nanshan granites provided metallogenic material,thermal source,hydrothermal fluid for mineralization, and represented as the minerogenetic parent rocks of the Nanshan tungsten-molybdenum polymetallic deposit. Basing on the characteristics of evolution of Nanshan granites and features of the deposit, this paper testified systematically relationship between Yanshanian granite pluton-related tungsten-tin polymetallic deposit in the Nanshan area,in which skarn type,quartz vein type are formed (controlled by joints and cracks) and granite type tungsten tin polymetallic ore bodis from top to bottom in the granite pluton.更多还原