【作者】 王策；

【导师】 吴淦国；

【作者基本信息】 中国地质大学（北京） ， 构造地质学， 2010， 硕士

【摘要】 巴根黑格其尔铅锌多金属矿床位于内蒙古兴安盟地区,是一个以铅锌为主,兼含铁、铜等金属的多金属矿床。通过野外工作,可见二长斑岩同大理岩所接触,二者之间产生矽卡岩化并且可见矿体,可见闪锌矿、黄铜矿、方铅矿,脉石矿物主要有方解石、石榴石、萤石、石英、绿泥石等,因此可判断该矿床成矿类型之一为矽卡岩型。通过镜下岩石特征的鉴定,可以判断出在成矿区总共有四个组的岩石存在,包括满克头鄂博组(J3mk)、玛尼吐组(J3mn)、白音高老组(J3b)以及大石寨组(P1d),另外可见花岗斑岩和二长斑岩两种侵入岩可见,这两种酸性岩同矿体形成关系密切。通过对矿区内石英和碳酸盐包裹体的温度测试,石英中气液相流体包裹流体均一温度范围为190°~270°,大部分集中在210°~250°,平均温度为243.66°。碳酸盐中气液相流体包裹体均一温度为170°~230°,大部分集中在190°~230°,平均温度为206°。经野外观察可以判断,石英形成应早于矿体形成,碳酸盐应与成矿时间相当,该温度在一定程度上表明该矿床为中温条件下形成的矿床。而由δ18O-δD图解可得,石英和碳酸盐来源是由大气降水和岩浆水混合形成。从石英和碳酸盐中氢氧同位素δD-δ18O投图可得,形成顺序为石英→细粒碳酸盐→粗粒碳酸盐。同时,从硫铅同位素结果可知,①硫元素为幔源物质,侏罗纪末期区域,处于挤压阶段,大量火山岩形成,岩浆热液携带大量地幔以及中下地壳物质上升,后在大石寨组(P1d)蚀变安山岩内沉淀;岩浆岩携带Pb2+、Zn2+等阳离子沿北东向断裂上升,同大石寨组变质安山岩中大量S2-相结合,形成金属硫化物;②铅同位素数据,表明矿区硫化矿物中主要是来源于造山带,这同区域上大兴安岭地区所处的构造环境是相吻合的。另外,含有Pb2+的成矿流体应为矿区内所产出的花岗斑岩和二长斑岩等所带来,其来自于中下地壳,且受地幔影响。该矿床由于长期火山喷发时的火山热液携带了大量的成矿物质富集在火山碎屑岩及凝灰岩中,后期的热液淬取火山碎屑岩、凝灰岩中的成矿物质,沉淀而形成金属硫化物矿。根据矿床的产出、充填方式,矿石结构、构造特点,矿物及元素共生组合、典型蚀变,矿床类型为矽卡岩型以及中温热液蚀变型。燕山晚期花岗斑岩、二长斑岩等侵入岩侵入含矿岩性内部,矿体的形成与岩体有着密切的关系,分析认为矿床的形成时代为燕山晚期。其控矿因素主要为断层控矿和岩体控矿。更多还原

【Abstract】 Bagenheigeqier lead-zinc polymetallic deposit lays in the Xing’an District, in the province of inner Mongolia, which is polymetallic deposit with lead and zinc mostly, iron and copper and so on. During the field work, ivernite keeps touch with the marble, and between both skarn happens with the ore. In the deposit, sphalerite, pyrite, galena can be seen, at the same time, gangue minerals conclude calcite, garnet, fluorite, quartz, chlorite and so on. So the conclusion that one forming type of the deposit is skarn deposit.With the help of the optical rock features, there are totally four groups of rocks in the deposit, including J3mk,J3mn, J3b and P1d. Granite porphyry and ivernite also outcrops in the district, which have the relationship with the deposit ore.During the temperature of fluid inclusion in the quartz and carbonate, the limit of the homogenization temperatures of quartz and carbonate are 190°~270°and 170°~230°, mostly 210°~250°and 190°~230°, and the average is 243.66°and 206°. During the field job, quartz forms latter than the ore, and carbonate is close to it, so, to some extent, the temperature indicates that this deposit formed in the moderate temperature condition. At the same time, according to theδ18O-δD diagram, quartz and carbonate are the results of the atmospheric precipitation and magmatic water, and from another diagram, the forming sequence can be judged that is quartz, fine-grain carbonate and coarse carbonate by the time.According to the sulfur-lead isotopic elements data, such conclusions can be drawn:①Sulfur element comes from mantle, when regional structural surrounding is compressing at Jurassic Period. Plenty of volcanic rocks form, while magmatic thermal which contains mantle and low-and-up crust matter upwell, and the matters precipitate in the altered andesite; magmatic rocks which contain Pb2+、Zn2+and other ions upwell along the N-E fracture, and then mix with the S2- in the altered andesite, so the metallic sulfide precipitate.②From the lead isotopic elements data, it’s the conclusion that the sulfides in the deposit district are coming from the orogenic belt, which is accorded with the fact that this regional structural background. The mineralizing fluid hosting the lead ion are supposed to get from the granite porphyry and ivernite in the deposit district, which comes from lower-middle crust and are influenced by the mantle.Long-time magmatic hydrothermal fluid containing so much mineralizing matter concentrating in the magmatic clastic rock and tuff, and latter hydrothermal fluid got the mineralizing matter, and then the metallic sulfide formed. According to the output, the style of the filling up, composition of the ore, and so on, the style of the deposit is skarn deposit and moderate hydrothermal alteration deposit,.Yanshan late period granite porphyry, ivernite and other intrusive rock intrude the ore-hosting rock, and the formation of the ore has close connection with the magmatic rocks. Analysis gets it that ord-forming period is Yanshan late period. The factor that controls the deposit is fault and rock mass.更多还原