云南省马关县都龙锌锡多金属矿床—岩浆作用及矿床成因研究

发布时间：2018-01-30 17:38

  本文关键词： 都龙锌锡多金属矿床 老君山花岗岩 层状矽卡岩 地球化学 矿床成因　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：本次研究选取我国著名的都龙锌锡多金属矿床为研究对象,以详实的野外地质调查为基础,岩浆-构造-流体-成矿为主线,系统的研究了矿区岩浆岩的地球化学特征、矿床的地质特征和矿床地球化学特征,从而对该矿床的成矿物质来源、矿床成因及成矿机制进行探讨。通过本次研究工作,获得了以下主要认识:(1)分别对矿区内出露的老君山花岗岩和南温河花岗片麻岩体进行了LAICP-MS锆石U-Pb测年、地球化学、同位素地球化学等方面的分析研究。实验结果表明,老君山花岗岩形成于晚白垩纪(88~83Ma),岩石地球化学特征为高分已S型花岗岩,形成于同碰撞向拉伸转换阶段,源区原岩以变质泥岩为主;南温河花岗片麻岩形成于晚志留纪(411Ma),岩石地球化学特征表现为S型花岗岩,形成于后碰撞拉伸背景,源区原岩以变质砂岩为主。(2)矿体形态不规则,主要以层状、似层状、透镜状、脉状和条带状等产出,常见分枝复合、尖灭再现、膨胀收缩和穿层交叉等现象。围岩蚀变包括矽卡岩化、绿泥石化、绿帘石化、绢云母化、碳酸盐化等。矿石类型包括块状矿石、浸染状矿石、条状带矿石、斑杂状矿石和脉状矿石。成矿期次可划分为矽卡岩期、热液成矿期和表生氧化期。(3)矽卡岩矿物的电子探针研究表明,都龙矿床中的矽卡岩主要以钙矽卡岩为主,成矿环境具有从弱氧化环境向还原环境转变的特点。同时,矿区中的层状矽卡岩是岩浆热液在地层层间滑脱带或破碎带流动过程中,通过渗透交代作用与碳酸盐围岩发生反应所形成。(4)都龙锌锡多金属矿床流体包裹体主要包括三种类型:富液相包裹体、富气相包裹体和含子矿物三相包裹体,包裹体气相成分以CH_4+CO_2±N_2为主。流体的温度、盐度和密度具有从早期到晚期逐渐降低的特点。(5)对都龙矿床铜街矿段的锡石单矿物样品进行LA-ICP-MS锡石U-Pb成矿年代学研究,获得88±5Ma的等时线年龄和89.4±1.4Ma的谐和年龄,表明都龙锌锡多金属矿床的形成与老君山岩浆作用关系密切。(6)通过对矿区不同阶段石英、方解石、磁铁矿的氢、氧同位素研究,都龙锌锡多金属矿床的成矿流体早期源于原生岩浆水,晚期变为以天水为主的混合流体;碳、氧同位素研究表明含矿热液的碳来源于岩浆热液,与围岩地层并无亲缘性;矿区主要硫化物的硫同位素来源于花岗质岩浆,与地层中硫化物的硫同位素相差较大;铅同位素研究表明,都龙锌锡多金属矿床成矿物质的铅同位素组成来源于老君山花岗岩源区。综上所述,本次研究的都龙锌锡多金属矿床为一岩浆热液矽卡岩型矿床,其中矿化与老君山二期花岗岩最为密切。
[Abstract]:This study selected China's famous Dulong zinc tin polymetallic deposit as the research object, based on field geological investigation and detailed basis of magmatic tectonic fluid mineralization system as the main line, the study of the geochemical characteristics of mine magmatite, geological features and ore deposit characteristics of the earth, and the source of ore the material of the deposit, discusses the genesis and metallogenic mechanism of ore deposit. Through this research, the main conclusions are as follows: (1) were within the mining area Laojun Mountain Nanwenhe granite and granite gneiss body exposed by LAICP-MS zircon U-Pb dating, geochemistry, isotope geochemistry analysis etc.. The experimental results show that the Laojun Mountain granite formed in the late Cretaceous (88~83Ma), rock geochemistry has high as S type granite, the conversion stage tensile in collision formation, original rocks by metamorphic mudstone The main; Nanwenhe granite gneiss formed in late Silurian (411Ma), rock geochemistry features of S type granite, formed in the post collision stretching background, the original rock source area by metamorphic sandstone. (2) the orebody shape is irregular, mainly layered, stratoid, lenticular, vein and ribbon etc. output, common branching, pinch reproduction, expansion and contraction and wear layer cross phenomenon. The wall rock alteration includes skarn, chloritization and epidotization, sericitization, carbonation etc.. Ore types include massive ore, disseminated ore, ore strip, taxitic ore and ore vein. The metallogenic period can be divided into skarn stage, hydrothermal stage and supergene oxidation stage. (3) electron microprobe study of skarn minerals show that the Dulong ore deposits in skarn mainly calcareous skarn metallogenic environment has mainly from weak oxidation environment to the characteristics of reducing environment change. The same When the layered silicates in the mining area is the skarn magmatic hydrothermal formation in the interlayer gliding belt or belt in the process of flowing, formed by infiltration metasomatism with carbonate rock reaction. (4) are in fluid inclusions of zinc tin dragon polymetallic ore body mainly includes three types: rich liquid inclusion rich. Vapor inclusions and halite bearing three-phase inclusions, gas composition of fluid inclusion in CH_4+CO_2 + N_2. The fluid temperature, salinity and density is decreased gradually from early to late. (5) cassiterite samples of copper ore section of longkuang bed street LA-ICP-MS study on metallogenic chronology of cassiterite U-Pb, obtained 88 + 5Ma isochron age of 89.4 + and 1.4Ma concordant age, indicate the formation of Dulong zinc tin polymetallic deposit and Laojun Mountain magmatism closely. (6) by the mining area in different stages of quartz, calcite, magnetite, hydrogen, oxygen isotope studies, all The early ore-forming fluid source zinc tin dragon polymetallic deposit in primary magmatic water, advanced into mixed fluid in Tianshui mainly; carbon, oxygen isotope studies show that the ore bearing hydrothermal carbon derived from magmatic hydrothermal fluid, and the surrounding strata no affinity; the main source of sulfur isotope sulfide mine in granitic magma, and sulfur the formation of sulfide in different isotope; lead isotope studies indicate that the Dulong zinc tin polymetallic ore deposit mineral composition of lead isotope from Laojun Mountain granite source region. In summary, the study of the Dulong zinc tin polymetallic ore deposit is a magmatic hydrothermal skarn deposit, the mineralization and granite the Laojun Mountain two close.

【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.2
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本文编号：1476837