内蒙古红花尔基白钨矿矿床花岗岩成因类型及成矿意义  

Genetic types and ore_forming geological significance of granites in the Honghuaerji scheelite deposit, Inner Mongolia

作　　者：郭志军[1,2] 李进文[1] 常裕林 韩增光 董旭舟[5] 杨郧城[1] 田京[1,5] 佘宏全[1] 向安平[1] 康永建[1] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]北京矿冶研究总院矿物加工科学与技术国家重点实验室,北京100044 [3]山东正元地质勘查院,山东济南250101 [4]内蒙古自治区第六地质矿产勘查开发院,内蒙古海拉尔021008 [5]中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石矿物学杂志》2015年第3期322-342,共21页Acta Petrologica et Mineralogica

基　　金："973"资助项目(2013CB428805);地质调查资助项目(科[2013]01-042-003)

摘　　要：红花尔基白钨矿矿床位于内蒙古自治区呼伦贝尔市海拉尔南120 km处,为大兴安岭中北段近年来新发现的规模有望达到大型的钨矿床,也是本地区到目前为止发现的唯一的白钨矿矿床。赋矿围岩是侵入奥陶系裸河组（O2-3lh）地层中的花岗岩体,岩性主要为二长花岗岩和石英二长岩。对赋矿花岗岩进行的LA-MC-ICP-MS锆石U-Pb定年结果表明：肉红色二长花岗岩的加权平均年龄为179.2±0.6 Ma（N=20,MSWD=1.3）;灰白色二长花岗岩的加权平均年龄为179.0±0.6 Ma（N=20,MSWD=0.7）;石英二长岩的加权平均年龄为178.6±0.7 Ma（N=20,MSWD=0.6）。这一结果表明上述花岗岩为燕山早期早侏罗世岩浆活动的产物。在3件花岗岩样品中均发现继承性锆石（年龄为779.1 Ma和463.2-486.0 Ma）,说明本区可能具有新元古代和早中奥陶世的基底。岩石地球化学数据表明,与成矿密切相关的3种花岗岩具有相似的地球化学特征,即：均以高硅（Si O2=63.09%-73.53%）、富碱（ALK=7.60%-8.74%）和整体弱过铝质（A/CNK=0.97-1.08）为特征。轻稀土元素相对富集,重稀土元素相对亏损[（La/Yb）N=3.96-12.28],整体具中等铕负异常（δEu=0.55-1.01）。在微量元素原始地幔比值蛛网图上主要显示大离子亲石元素富集,高场强元素亏损的特点,Rb、Th、U、K、Pb等元素富集,Ba、Nb、Ta、Sr、P、Ti等元素明显亏损。岩石地球化学特征显示其为典型的I型花岗岩。经过分析认为,矿床的成矿物质主要来自于下地壳,岩浆上侵过程中也可能萃取含钨建造中的钨等元素。Located about 120 km south of Hailar City in Hulun Buir League,the newly-discovered Honghuaerji scheelite deposit is the only scheelite deposit in central-northern section of Da Hinggan Mountains. The ore-bearing granites comprising monzogranites and quartz monzonite intruded into the Ordovician Luohe Formation（ O2-3lh）.The LA-MC-ICP-MS zircon U-Pb dating results show that the reddish monzogranite was formed at 179. 2 ± 0. 6 Ma（ N = 20,MSWD = 1. 3）,the gray monzogranite was formed at 179. 0 ± 0. 6 Ma（ N = 20,MSWD = 0. 7） and the quartz monzonite was formed at 178. 6 ± 0. 7 Ma（ N = 20,MSWD = 0. 6）. The high concordance of the dating results indicates that they were formed by magma activities in Early Jurassic. The inherited zircon（ 779. 1 Ma and463. 2 - 486. 0 Ma） has also been found in the three granites,which indicates that the Neoproterozoic and Lower-Middle Ordovician blocks are probably existent in the study area. The three granites have similar petrogeochemical characteristics. Geochemical analysis shows that all of the three rocks have high Si O2（ 63. 09% - 73. 53%） and K2 O ＋ Na2O（ 7. 60% - 8. 74%）,and are slightly peraluminous（ A / CNK = 0. 97 - 1. 08）. They are enriched in light rare earth elements and depleted in heavy rare earth elements [（ La / Yb）N= 3. 96 - 12. 28] with a medium negative Eu anomaly（ δEu = 0. 55 - 1. 01）. They are also enriched in Rb,Th,U,K,Pb and depleted in Ba,Nb,Ta,Sr,P,Ti. The analytical results of main and trace elements show that they are typical I-type granites.The ore-forming materials were mainly derived from the lower crust and also extracted from the tungsten-bearing formation by the magma.

关 键 词：白钨矿矿床 I型花岗岩 早侏罗世 锆石U-Pb定年 岩石地球化学 成矿物质来源 红花尔基 

分 类 号：P588.121[天文地球—岩石学] P595[天文地球—地质学]