东秦岭黄龙铺矿田桃园Mo矿床成因研究:来自矿物学及辉钼矿Re-Os同位素的约束  

GENESIS OF TAOYUAN Mo DEPOSIT IN HUANGLONGPU ORE FIELD,EAST QINLING MOUNTAINS:CONSTRAINTS FROM MINERALOGY AND MOLYBDENITE Re-Os ISOTOPE

作　　者：张焱 刘畅 彭义伟[1,3] 田建吉 何德宝[2] 宋明伟[1] 王智 徐世朴 ZHANG Yan;LIU Chang;PENG Yiwei;TIAN Jianji;HE Debao;SONG Mingwei;WANG Zhi;XU Shipu(College of Earth Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Key Laboratory of Uranium Resources Erploration and Evaluation Techniques,Beijing Research Institute of Uranium Geology,Beijing 100029,China;College of Earth Science and MLR Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation,Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]铀资源勘查与评价技术重点实验室,核工业北京地质研究院,北京100029 [3]成都理工大学、自然资源部构造成矿成藏重点实验室,四川成都610059

出　　处：《矿物岩石》2023年第1期73-84,共12页Mineralogy and Petrology

基　　金：中国核工业地质局铀矿地质科研项目(编号:地D2003);中国核工业地质局地勘费项目(编号:地GT2201)。

摘　　要：黄龙铺矿田是东秦岭钼成矿带中比较特别的钼矿田,产有两种矿床类型:一种以大石沟为代表的碳酸岩脉型钼矿床,另一种是以石家湾为代表的斑岩型钼矿床。桃园钼矿床位于黄龙铺矿田西南方向,含矿脉体为长石-石英脉。前人多从宏观地质特征对桃园钼矿床的成因进行讨论,缺乏系统的矿物学和年代学研究,其成因类型具有较大的争议。本次研究通过矿物-元素组合的鉴定和辉钼矿Re-Os同位素定年,旨在对桃园钼矿床的成矿时代、成矿地质背景以及矿床成因类型进行约束。桃园钼矿床矿石中辉钼矿普Os含量在0.0105±0.0061×10^(-9)~0.0231±0.0012×10^(-9),^(187),Re^(187)Os 的相对误差均定为2.0%(2σ)。Re-Os同位素的模式年龄为224.2±3.5~218.6±3.6 Ma,等时线年龄为221.1±9.7 Ma(MSWD=2.6),表明该矿床形成于晚三叠世,其钼矿化可能与扬子板块和华北板块全面碰撞关系密切。利用扫描电镜-能谱成分分析对矿石中的矿物组成进行测试分析,结果显示矿石中除常见的辉钼矿、黄铁矿等矿物外,还伴生有许多富含REE、Nb-Ta的矿物,如氟碳铈矿、独居石、磷钇矿、含Nb金红石、天青石等。同时矿床中除Mo元素达到工业品位以外,Y,Ce,Pb,Ga等不少伴生元素也达到了工业品位,与典型的碳酸岩脉型矿床元素组合和矿物共生组合特征相似。对比区域上典型的碳酸岩脉型钼矿床,其成矿时代范围也基本一致,综上认为桃园钼矿床成因类型为与碳酸岩脉型钼矿具有一定成因联系的热液型钼矿床。Huanglongpu ore field in East Qinling molybdenum metallogenic belt has two types of deposit,one is carbonate dike type molybdenum deposit represented by Dashigou deposit,the other is porphyry type molybdenum deposit represented by Shijiawan deposit.Taoyuan molybdenum deposit,located in the southwest of Huanglongpu ore field,has feldspar-quartz veins as the ore-bearing rock.Previous studies mainly focused on the macroscopic geological characteristics and the discussion on the genetic types of Taoyuan molybdenum deposit,but the systematic mineralogy and chronology studies are relatively neglected.In this paper,the mineral-element association of Taoyuan molybdenum deposit is identified and the Re-Os isotope dating of molybdenite is carried out to constrain the metallogenic age,metallogenic geolog-ical setting and genetic type of Taoyuan molybdenum deposit.The results show that the content of com-mon Os of molybdenite in Taoyuan molybdenum deposit is 0.0105±0.0061 ×10^(-9) to 0.0231±0.0012 × 10^(-9)and the relative error of ^(187)Re and ^(187)Os is 2.0%(2σ).The model age of Re-Os isotope obtained ran-ges from 224.2±3.5 Ma to 218.6±3.6 Ma,and the isochron age is 221.1±9.7 Ma(MSWD=2.6),indicating that the deposit was formed in the Late Triassic,and its molybdenum mineralization may be closely related to the comprehensive collision between the Yangtze Plate and the North China Plate.SEM-energy spectrum analysis for the mineral composition in the ore indicates that,in addition to the common minerals such as molybdenite and pyrite,there are also many minerals rich in REE and Nb-Ta,such as fluocerite,monazite,xenotime,Nb rutile,lapis lazuli and so on.Meanwhile,in addition to Mo element reaching in-dustrial grade,many associated elements such as Y,Ce,Pb and Ga also reach industrial grade,which is similar to the characteristics of element association and mineral association in typical carbonate dike deposits.Comparison with typical carbonate dike molybdenum deposits in the region shows that their metallogenic age ran

关 键 词：桃园钼矿床 辉钼矿RE-OS定年 元素组合 矿物共生组合 东秦岭 

分 类 号：P618.2[天文地球—矿床学]