【作者】 王长虹；

【导师】 吴国学；

【作者基本信息】 吉林大学 ， 矿产普查与勘探， 2020， 硕士

【摘要】 黑龙江省嫩江县三矿沟地区处于兴蒙造山带东段,兴安地块与松嫩地块分界断裂（贺根山–黑河断裂带）西侧,位于多宝山—三矿沟成矿带西北端。三矿沟地区除发育成型的三矿沟矽卡岩型铁铜矿以外,近期的找矿勘查工作,在其外围地区发现了斑岩型铜钼矿化。该类矿化主体产于花岗闪长岩内,呈细脉状和透镜状产出。依据矿物组合、矿脉穿切关系将铜钼多金属热液成矿作用划分为:I石英-黄铁矿阶段,II石英-黄铁矿-辉钼矿±黄铜矿阶段及III黄铁矿-闪锌矿-石英三个阶段。流体包裹体岩相学及显微测温研究结果显示,三矿沟地区铜钼矿化I、II阶段主要发育气液两相型、富气相型和含NaCl子矿物三相型三种类型原生包裹体,成矿流体为中-高温（Th=170.4³37.8℃）高盐度（31.26⁴1.01 wt.%NaCl eqv.）不均匀的NaCl-H₂O体系热液,III阶段仅发育气液两相型包裹体,成矿流体为低温（Th=122.3²13.4℃）低盐度（2.06⁷.99 wt.%NaCl eqv.）均匀的NaCl-H₂O体系热液。氢氧同位素组成(δD=-90.2‰^-96.8‰;δ¹⁸O=-2.1‰⁴.0‰)显示该区成矿流体早期来源于岩浆水,而到晚期逐渐演化为以大气降水来源为主,硫、铅同位素研究显示成矿物质来源具壳幔混源的特征。区内铜钼矿化产于花岗闪长岩岩体内,具有斑岩型矿化特征,因此,含矿花岗闪长岩岩体即为成矿岩体。锆石U-Pb定年分析结果显示区内的花岗闪长岩和闪长岩的形成年龄分别为167.1±1.6Ma和165.9±1.5Ma,表明区内铜钼热液成矿作用时代为中侏罗世。岩石地球化学分析结果表明,花岗闪长岩体具有高钾钙碱性系列及准铝质-弱过铝质系列特征,呈轻稀土富集和重稀土亏损,富集大离子亲石元素,亏损高场强元素的特征。三矿沟地区斑岩型矿化受环形断裂控制及中侏罗世花岗质岩浆活动控制,为该区必要成矿地质条件。钾化、硅化;中侏罗世中酸性侵入岩;北西向及环形构造;Mo、W、Ag、Au、Bi、Cu等元素土壤组合异常与高磁梯度带且低阻高极化异常为该区铜钼矿化的找矿标志。在综合分析三矿沟地区的地质特征、铜钼矿化成因,控矿地质条件以及地质、地球物理、地球化学找矿标志基础上。利用MRAS矿产资源评价系统开展综合预测甄选出四个找矿靶区,为该区进一步勘查找矿工作指明了方向。更多还原

【Abstract】 The Sankuanggou area,Nenjiang county,Heilongjiang province,located in the eastern part of the Xingmeng orogenic belt,west of the boundary fault between the xing’an block and the Songnen block（Hegenshan-Heihe fault zone）,is occurred in the northwestern part of the Duobaoshan-Sankuangou metallogenic belt.In addition to the Sankuanggou skarn-type Fe-Cu deposit,recent prospecting work has found porphyry molybdenum mineralization around the areas.This type of mineralization is produced in granodiorite.Based on the mineral assemblages and cross-cutting relationships of ore veins,the ore-forming process were divided into three stages:quartz–pyrite（stage I）,quartz-pyrite-molybdenite±chalcopyrite（stage II）,III pyrite-zincite-quartz（stage III）.The fluids of stage I and II were composed of gas-rich,NaCl-containing and gas-liquid type fluid inclusions with homogenization temperatures and salinities of 170.4to 337.8℃and 31.26 to 41.01wt%NaCl eqv.,respectively.The fluids of stage III was composed of gas-liquid type fluid inclusions with homogenization temperatures and salinities of 122.3 to 213.4℃and 2.06 to 7.99 wt%NaCl eqv.,respectively.The initial ore-forming fluids of the Sankuanggou area had Mid-high temperature,high salinity,and belonged to a NaCl–H₂O system.The fluids gradually evolved to low temperature,low salinity,and belonged to a NaCl–H2O system.Studies of the hydrogen and oxygen isotope of quartz(δD=-90.2‰^-96.8‰;δ¹⁸O=-2.1‰⁴.0‰)show that the ore-forming fluids gradually evolved from magmatic water to meteoric water.Sulfur and lead isotopic studies show that the ore-forming materials mainly derived from the mantle and crustal.The Cu-Mo mineralization in the area is produced in the granodiorite body,which has the characteristics of porphyry mineralization.The zircon U-Pb geochronology results show that the ages of granodiorite and diorite formation in the area are 167.1±1.6Ma and165.9±1.5Ma,respectively.Therefore,it is believed that the main metallogenic occured in the Middle Jurassic.Granodiorite rock belong to the characteristics of high-K calc-alkaline series and weakly peraluminous rocks.It is enriched in LILEs and LREEs and depleted in HFSEs and HREEs.The porphyry Cu-Mo mineralization are controlled by annular fault and Middle Jurassic granitic magmatism.Mineralization,which is necessary ore-forming geological condition of this area.Potassiumization and silicification;middle Jurassic acid intrusive rock;NW and ring structure,the Mo-W-Ag-Au-Bi-Cu prospecting element combination,the high magnetic gradient zone,and the low-resistance and high-polarization anomaly are the signs of direct prospecting in this area.Combined with the geological,geophysical and geochemical characteristics of the Sankuangou area,the next prospecting direction of the area is defined.Four prospecting target areas were selected by the comprehensive forecast of MRAS mineral resources evaluation system.更多还原