青海玉树撒纳龙哇铜矿床地质特征及矿化富集规律

发布时间：2018-02-26 02:07

  本文关键词： 撒纳龙哇铜矿 矿床地质特征 热水沉积 喷流岩 矿床成因 矿化富集规律　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：撒纳龙哇铜矿床位于青海省三江地区北西段的主体,其大地构造位置处于欧亚大陆南缘、扬子古陆西缘,东坝-澜沧江缝合带北侧的古特提斯构造域北特提斯华力西-印支期造山系的唐古拉陆块内。矿区出露的地层主要有晚三叠世巴塘群火山岩和灰岩组,并有少量沉积岩重晶石岩出露。赋矿地层主要为英安质岩屑晶屑凝灰岩、安山质岩屑晶屑凝灰岩、玄武质凝灰岩等。其中矿区玄武质凝灰岩锆石U-Pb年龄为237.5±2.9Ma。玄武质凝灰岩地球化学研究表明,Mg#值平均为50.49,大于地幔岩浆的Mg#值;δEu范围为1.08~1.69,说明源区没有斜长石的分离结晶作用;(Th/Ta)PM值为1.08~6.46、(La/Nb)PM值为3.97~11.66、(Th/Nb)PM平均值为6.67、TDM1值为792-886Ma,表明岩石的原始岩浆应起源于亏损地幔,同时受到了地壳物质或者富集地幔组分的混染。岩石具有钙碱性系列岛弧玄武质特征,同时具有一定的洋中脊(MORB)的属性。位于HS46号异常区东南侧,圈出1个(ⅠCuPbZn)矿体,矿体控制长度1600m,宽度4.94-13.34m,Cu品位1.55%,Pb品位2.94%,Zn品位4.69%。位于HS37号异常区,圈出1个铜(ⅡCu)矿体,矿体长大于200m,厚度6.71m,Cu品位0.84%。野外调究和室内分析确定矿床的两套成矿系统:即通道相周围具有明显的矿化,围岩为火山岩;沉积相中发育各种重晶石岩、铁硅质岩等。两个矿体的金属矿物主要为黄铜矿、黄铁矿、方铅矿和闪锌矿。矿石结构主要为自形结构、半自形-它形晶结构、脉状穿插结构、交代残余结构、骸晶结构。矿石构造主要为浸染状构造、条纹状或条带状构造、脉状或网脉状构造、薄膜状构造。围岩蚀变主要为硅化、绿泥(帘)石化、绢云母化、碳酸盐化等。并确定了该矿床经历了热水喷流沉积成矿期和表生氧化期两个成矿期。流体包裹体研究表明,通道相石英中成矿流体为中低温(180~220℃)、低盐度(1~5wt%NaCl)、低密度(0.84~0.92g/cm3)流体;沉积相重晶石岩中成矿流体为低温(140~160℃)、低盐度(8.8~9.6wt%NaCl)、低密度(0.92~0.94g/cm3)流体。硫同位素研究表明,黄铜矿中硫同位素δ34S的均值为-1.9,黄铁矿中硫同位素δ34S变化范围为-0.6~-0.3之间,表明深部岩浆硫或幔源硫的特点。重晶石样品硫同位素(δ34S)分析结果为15.5和15.8,代表了晚三叠世海相蒸发岩δ34S的特征。厘定了成矿时代为赋矿围岩玄武质凝灰岩的形成时代,即晚三叠世。综合分析认为,撒纳龙哇铜矿床为热水喷流沉积矿床。通过地质模型、物化探模型等对该矿床矿化富集规律进行分析,认为构造错断影响、重晶石岩与矿化的关系、(Au、Ag、Cu、Pb、Zn)组合异常、地磁异常正负交替是找矿的重点地区。
[Abstract]:The Xanalongwa copper deposit is located in the main body of the northern western section of Sanjiang area, Qinghai Province, and its tectonic position is located in the southern margin of Eurasia and the western margin of Yangtze paleocontinent. On the north side of Dongba Lancang River suture belt, the northern Tethys West to Indosinian orogenic system in the Tangguula block. The strata exposed in the mining area are mainly volcanic rock and limestone formation of the late Triassic Batang Group. A small amount of sedimentary barite rocks are exposed. The ore-hosting strata are mainly clastic tuff tuff, andeshanite crystalline tuff tuff. The zircon U-Pb age of Black Tortoise tuff in the mining area is 237.5 卤2.9 Ma.The geochemistry study of Black Tortoise tuff shows that the average value of tuff is 50.49, which is larger than the Mg# value of mantle magma, and the 未 EU range is 1.08U 1.69, indicating that there is no plagioclase in the source area. The PM value of the isolated crystallization process is 1.08% 6.46% La / NbO PM value 3.97% 11.66% T / NbO PM average value is 6.67% TDM1 value is 792-886 Ma.This indicates that the original magma of the rocks should have originated from the depleted mantle, and the average value is 7.67% TDM1, which indicates that the original magma of the rocks originated from the depleted mantle. The rocks are characterized by a series of calc-alkaline island arc Black Tortoise and a certain attribute of the mid-oceanic ridge MORB.The rocks are located on the southeast side of the HS46 anomaly area and are surrounded by a (鈪，

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