黑龙江鹿鸣钼矿区花岗质杂岩锆石U-Pb年龄、Hf同位素、辉钼矿Re-Os年龄及其地质意义  

Zircon U-Pb ages,Hf isotopes of the granitoids and Re-Os ages of the molybdenites in Luming molybdenum ore area,Heilongjiang Province,and its geological significance

作　　者：程国华[1,2] 王瑞良[3] 曾庆栋[1] 郭云鹏[1,2] 段晓侠[1,2] 魏金江 张俊生 高秀航 

机构地区：[1]中国科学院矿产资源研究重点实验室、中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]石家庄经济学院,石家庄050031 [4]中铁资源伊春鹿鸣矿业有限公司,伊春152500

出　　处：《岩石学报》2015年第8期2450-2464,共15页Acta Petrologica Sinica

基　　金：国家自然科学基金重大项目(41390443);国家重点基础研究发展计划(973计划)(2013CB429804)联合资助

摘　　要：鹿鸣超大型钼矿（钼金属量89万吨,平均品位0.084%）产于小兴安岭-张广才岭成矿带北段,矿体呈细脉浸染状赋存于二长花岗斑岩和二长花岗岩体内,围岩蚀变有钾化、绢云母化、硅化、绿泥石化、碳酸盐化等,矿化类型主要为斑岩型矿化。鹿鸣矿区含矿岩体二长花岗斑岩和二长花岗岩的锆石U-Pb定年、Hf同位素及辉钼矿Re-Os同位素定年研究表明：二长花岗岩和二长花岗斑岩锆石的U-Pb年龄分别为186.8±2.1Ma和183.2±1.9Ma,形成于燕山早期,二长花岗斑岩晚于二长花岗岩。6个样品辉钼矿Re-Os等时线年龄为176.7±4.4Ma（MSWD=0.92）,Re含量变化于30×10-6~49×10-6。二长花岗岩的锆石εHf（t）值变化于1.1~3.8,Hf单阶段模式年龄为729Ma,两阶段模式年龄为1055Ma;二长花岗斑岩的锆石εHf（t）值变化于0.4~5.9,Hf单阶段模式年龄为741Ma,两阶段模式年龄为1075Ma。研究表明成矿与二长花岗斑岩有关,并且二长花岗岩和二长花岗斑岩岩浆为中新元古代新生的地壳物质熔融的产物,成岩成矿作用与古太平洋板块俯冲作用（或佳木斯与松嫩地块的拼合）有关。The giant Luming molybdenum deposit（ 0. 89 Mt Mo,average grade 0. 084%） is located in the north of the Lesser Xing＇an Range-Zhangguangcai Range metallogenic belt,and is characterized by the veinlet-disseminated mineralization. The mineralization occurs in the monzogranite porphyry and the monzogranite. The typical alteration in Luming porphyry deposit includes potassic alteration,sericitization,silicification,chloritization and carbonization. In order to define the genesis of the monzogranite and monzogranite porphyry and their relationship with mineralization,the zircon U-Pb dating,Hf isotope,and Re-Os isotope dating of molybdenite were carried out. The analysis results show that the zircon U-Pb ages of the monzogranite porphyry and monzogranite are186. 8 ± 2. 1Ma and 183. 2 ± 1. 9Ma,respectively. Six molybdenite samples yield an Re-Os isochron age of 176. 7 ± 4. 4Ma（ MSWD =0. 92）,which indicates that the mineralization is associated with the monzogranite porphyry. The εHf（ t） values of the monzogranite and the monzogranite porphyry are 1. 1 ~ 3. 8 and 0. 4 ~ 5. 9,respectively. The single and two stage model ages of the monzogranite and monzogrnaite porphyry are 729 Ma and 1055 Ma,741Ma and 1075 Ma,respectively. The Re isotopic compositions of molybdenites range from 30 × 10- 6to 49 × 10- 6,indicating that the ore-forming materials were mainly derived from crust. The studies show that the monzogranite and the monzogranite porphyry may be derived from magma melting by newly crust which formed in Early-Middle Proterozoic. Considering the regional tectonic background,we think that magmatism and mineralization in the Luming molybdenum deposit was hopefully related to the subduction of paleo-Pacific plate（ convergence of Jiamusi and Songnen massif）.

关 键 词：锆石U-PB定年 HF同位素 RE-OS定年 成岩成矿环境 鹿鸣斑岩钼矿 黑龙江省 

分 类 号：P597.3[天文地球—地球化学] P618.65[天文地球—地质学]