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.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
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)
作者简介
郭志军（1988-），男，硕士研究生，矿物学、岩石学、矿床学专业，E—mail：GHN_07@163．com
通讯作者：李进文（1964-），男，博士，研究员，主要从事矿床学和矿产勘查学研究，E-mail：lijinwen958@sohu．com。
