湘南铜山岭铅锌铜多金属矿床成矿时代与成矿物质来源研究

发布时间：2018-06-10 06:27

本文选题：湘南 + 铜山岭铅锌铜多金属矿床　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：铜山岭铅锌铜多金属矿床位于扬子地块湘南-桂东北拗陷与华夏地块粤北拗陷的拼贴部位,是我国南岭多金属成矿区代表性矿床之一。本论文在前人的研究基础上,查明铜山岭铅锌铜多金属矿床的地质和矿床特征、开展了Sm-Nd同位素地质年代学和Pb同位素地球化学示踪以及矿物流体包裹体的研究,获得的主要研究结果如下:对铜山岭铅锌铜多金属矿床的含矿矽卡岩中石榴子石开展了Sm-Nd同位素定年分析,获得等时线年龄173 Ma。该年龄值略早于卢友月等(2015)和Zhao等(2016)的成岩成矿年龄,但是与王岳军等(2001)的花岗闪长岩的成岩时代一致,属于燕山早期岩浆活动的产物,这表明铜山岭铅锌铜多金属矿床在燕山早期可能存在多期次成岩成矿作用,而本论文得到的173 Ma可能限定了该矿床的初次成矿事件。对铜山岭铅锌铜多金属矿床的金属硫化物矿物进行Pb同位素组成分析,得到206Pb/204Pb、207Pb/204Pb、208Pb/204Pb的平均值分别为18.602、15.701、38.729,具有明显的富放射性成因铅特征。此外,硫化物矿物铅μ均值为9.64,高于正常铅μ值范围;Th/U平均值为3.81,略低于正常铅的范围。以上均表明铜山岭铅锌铜多金属矿床铅源物质成熟度高,且相对富集铀铅,略微亏损钍铅,具有上地壳源区特点。在(207Pb/204Pb)i-(206Pb/204Pb)i铅同位素演化模式图中,金属硫化物矿物样品数据点主要分布在寄主花岗闪长岩的范围,表明寄主花岗闪长岩可能是铜山岭铅锌铜多金属矿床的重要物质来源。对铜山岭铅锌铜多金属矿床划分的成岩成矿阶段-矽卡岩阶段、石英-硫化物阶段、碳酸盐阶段进行矿物流体包裹体进行研究,结果表明成矿热液流体具有中-高温、中-低盐度、低密度的特征,其成岩成矿环境为浅成、低压。在流体包裹体均一温度与盐度关系图上,石英-硫化物阶段和碳酸盐岩阶段的流体包裹体均一温度和盐度重合部分,指示了热液流体在这两阶段的继承演化特征。此外,有些数据点靠近大气降水的温度和盐度范围,表明热液流体在成矿过程中可能受到了大气降水的影响。流体包裹体岩相学特征和显微测温结果表明,矽卡岩阶段和石英-硫化物阶段的流体包裹体可能是从非均匀流体中捕获的,代表了流体的不混溶特征。此外,由于铜山岭铅锌铜多金属矿床发育钾长石化和绢云母化等标志性的水-岩反应,也可能是促使流体中金属硫化物沉淀聚集的重要因素。
[Abstract]:The Copper Mt. ridge lead zinc copper polymetallic deposit is located in the southern Hunan cinnamon depression and the huaxibei depression in the Yangtze block and the northern and southern depression of the Huaxia block. It is one of the representative deposits of the Nanling polymetallic metallogenic area in China. On the basis of previous studies, the geological and ore deposit characteristics of the Copper Mt. Ling Pb Zn Cu polymetallic deposit were found out, and Sm-Nd isotopes were carried out. The main research results obtained by qualitative chronology, Pb isotope geochemical tracing and mineral fluid inclusions are as follows: the Sm-Nd isotope dating of the garnet in the ore bearing skarn of the Copper Mt. ridge lead zinc copper polymetallic deposit has been obtained, and the age of isochron age 173 Ma. is slightly earlier than Luo Yu Yue (2015) and Zhao (2). 016) the age of diagenesis and mineralization, but consistent with the diagenesis age of Wang Yuejun and (2001) granodiorite, is a product of early magmatism in Yanshan. This indicates that the Copper Mt. ridge lead zinc copper polymetallic deposit may have multiple stages of diagenesis in early Yanshan, and the 173 Ma in this paper may limit the initial mineralization of the deposit. The Pb isotopic composition of the metal sulfide minerals of the Copper Mt. ridge lead zinc copper polymetallic deposit is analyzed. The average value of 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb is 18.602,15.701,38.729, and the lead characteristics of the rich radioactive cause are obvious. In addition, the lead of sulfide minerals is 9.64, higher than the normal range of lead, and Th/U average. The value is 3.81, slightly below the range of normal lead. All above indicate that the lead source of the Copper Mt. Ling lead zinc copper polymetallic deposit has high maturity, and is relatively rich in uranium and lead, slightly depleted thorium and lead, and has the characteristics of the source area of the upper crust. In the (207Pb/204Pb) i- (206Pb/204Pb) I lead isotope evolution pattern, the data points of the metal sulfide minerals are mainly distributed in the mailing of the data points of the metal sulfide minerals. The scope of the main granite diorite indicates that host granodiorite may be an important source of material in the Copper Mt. Ling Pb Zn Cu polymetallic deposit. The metallogenic fluid inclusions in the diagenesis and mineralization stage of the Copper Mt. Ling Pb Zn Cu polymetallic deposit, the skarn phase, the quartz sulfide phase and the carbonate stage, have been studied. The fluid has the characteristics of medium to high temperature, medium low salinity and low density, and its diagenesis and metallogenic environment is shallow, low pressure. On the relationship diagram of the homogeneous temperature and salinity of fluid inclusions, the homogeneous temperature and salinity of fluid inclusions in the phase of quartz sulfide and carbonate rocks indicate the succession and evolution of the hydrothermal fluid in these two stages. In addition, some data points are close to the temperature and salinity range of the atmospheric precipitation, indicating that the hydrothermal fluids may be affected by atmospheric precipitation during the metallogenic process. The petrographic characteristics of the fluid inclusions and the results of microthermometry show that the fluid inclusions in the skarn phase and the quartz sulfide phase may be captured from the non-uniform fluid. The characteristics of fluid immiscibility are represented. In addition, the marked water rock reaction of the Copper Mt. ridge lead zinc copper polymetallic deposit, such as potassium long fossilization and sericite, may also be an important factor contributing to the precipitation and accumulation of metal sulfide in the fluid.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.2

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