陕西秦岭东部地区中生代钼、铜矿床时空分布规律、控矿因素及找矿潜力分析  

Spatial-temporal distribution, ore-controlling factors and prospecting potential of Mesozoic Mo, Cu deposits in East Qinling Mountains, Shaanxi Province

作　　者：代军治[1,2] 张西社 鱼康平 王瑞廷 高菊生 任涛 袁海潮 李剑斌 

机构地区：[1]西北有色地质矿业集团有限公司,陕西西安710054 [2]长安大学,陕西西安710054 [3]西北有色地质勘查局七一三总队,陕西商洛726000 [4]西北有色地质勘查局七一二总队,陕西咸阳712000

出　　处：《矿床地质》2016年第4期809-828,共20页Mineral Deposits

基　　金："十二五"国家科技支撑计划课题(编号:2011BAB04B05);西北有色地质矿业集团博士后项目;国土资源部公益性行业科研专项(编号:201111007-3)联合资助

摘　　要：陕西秦岭东部地区中生代钼、铜矿床成矿类型齐全,有斑岩型、斑岩-矽卡岩型、矽卡岩型、石英脉型和碳酸岩脉型。钼矿床主要分布在小秦岭地区,有向西秦岭过渡和向南秦岭延伸的趋势;铜矿床主要分布在南秦岭地区。除碳酸岩脉型钼矿床外,这些钼、铜矿床多与花岗质小岩体具有密切的成因联系,不受容矿地层的限制,成矿时代主要集中在晚三叠世—早侏罗世和晚侏罗世2个阶段,与共生岩体的成岩时代多数相同,个别相差在10 Ma内。赋矿岩体多受近EW向与NE向或NW向断裂构造交汇部位的控制,与钼矿床有关的成矿岩体显示高硅（w（Si O2）〉71%）、高钾（K2O/Na2O〉1）、中铁（w（TFe）=0.13%～2.45%）特征,而与铜矿床有关的岩体相对低硅（70%〉w（Si O2）〉62%）、中钾（K2O/Na2O〉0.88）、高铁（w（TFe）=1.9%～4.8%）。矿石、岩体和地层的S、Pb、Sr、Nd同位素组成显示,除晚三叠世碳酸岩脉型和石英脉型钼矿的成矿物质来源于Ⅰ型富集地幔外,早侏罗世—晚白垩世斑岩-矽卡岩型及石英脉型钼、铜矿成矿物质以壳幔混源为主,但铜矿比钼矿具有更多的幔源物质。地质和地球化学特征指示,南秦岭和北秦岭地区有形成斑岩型铜、钼矿床的有利条件,也有不利因素,不利因素导致南秦岭和北秦岭地区浅部不易形成大型斑岩铜、钼矿床,但形成小-中型铜、钼矿床的潜力大。There are many types of Mo, Cu deposits in eastern Shaanxi Province, comprising porphyry, porphyry- skarn, skarn, quartz vein and carbonatite vein types. Spatial distribution of Mo deposits tends to be transitional towards West Oinling and extends to south Qinling, and Cu deposits occur mainly in South Qinling area. These deposits have genetic relations with small granitic intrusions, and have no clear controlling influence from strata. The ore-forming ages of these deposits are mainly in two epochs： Late Triassic-early Jurassic and late Jurassic, close to the rock-forming age of the ore-bearing intrusive. The ore-bearing intrusive body is controlled by the intersection of the EW-striking and NE（NW）-striking faults. Geochemistry of the Mo-associated intrusions show w （SiO2） 〉71%, K2O/Na2O〉 1 and w （TFe） = 0.13% -2.45 %, while Cu deposits show 70% 〉 w （SiO2） 62%, K2O/Na2O〉0.88 and w（TFe）=1.9%-4.8%. S, Pb, Sr, Nb isotopic compositions of ores, granitic intrusions and strata show that the metallogenic materials were mainly derived from mixing between crustal material and lithospheric mantle for porphyry-skarn type and quartz vein type Mo Cu deposits, while EM-I type mantle materials for late Triassic carbonatite vein type or quartz vein type Mo deposits. Moreover, the Cu deposits have more mantle signatures than Mo deposits. From the view of exploration, their geological and geochemical characteristics show that there is less possibility to find larger Mo, Cu deposits in the shallow part of South Qinling and North Qinling areas; nevertheless, these areas have potential of forming small-middle sized vein type or porphyry type Mo, Cu deposits.

关 键 词：地球化学 钼、铜矿床 控矿因素 时空分布规律 成矿潜力 陕西东部 

分 类 号：P618.41[天文地球—矿床学] P618.65[天文地球—地质学]