大兴安岭南段安乐锡多金属矿床花岗斑岩年代学、岩石成因及成矿意义  

Geochronology,petrogenesis and mineralization of granite porphyry in Anle tin-based polymetallic deposit,southern Great Xing'an Range

作　　者：张静俊 王玉往[2] 邹滔[2] 管育春 Zhang Jingjun;Wang Yuwang;Zou Tao;Guan Yuchun(Faculty of Land and Resource Engineering,Kunming University of Science and Technology,Yunnan Kunming 650093,China;Beijing Institute of Geology for Mineral Resouces Co.,Ltd.,Beijing 100012,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]北京矿产地质研究院有限责任公司,北京100012

出　　处：《化工矿物与加工》2021年第10期28-35,共8页Industrial Minerals & Processing

基　　金：国家重点研发计划(2017YFC0601305,2017YFC0602403);中国地质调查局国家二级项目(DD20190815)。

摘　　要：安乐锡多金属矿床位于大兴安岭南段的黄岗梁-孟恩陶勒盖锡铁多金属成矿带南西段之北西成矿亚带,是一个中型富Sn矿床,其成矿岩体的成岩时代、岩石成因、成矿指示意义以及地球动力学背景尚不清楚。以与安乐Sn多金属矿床相关的花岗斑岩为研究对象,利用LA-ICP-MS锆石U-Pb方法测得与成矿有关的花岗斑岩年龄为(144±2.6)Ma(MSWD=3.2),这一年龄与区域其他Sn多金属矿床成矿岩体的成岩年龄范围基本一致,说明大兴安岭南段与Sn成矿作用有关的花岗质岩石主要形成于早白垩世。全岩主量、微量和稀土元素地球化学特征显示,花岗斑岩的SiO 2质量分数(75.76%~76.67%)、ω(FeO T)/ω(FeO T+MgO)值(0.9~1.0)、ω(FeO T)/ω(MgO)值(18.42~20.79)、ω(Ga)×10^(4)/ω(Al)值(3.36~4.61)、ω(MgO)(0.06%~0.07%)、ω(TiO_(2))(0.05%~0.06%)及P 2 O 5质量分数(0.01%)均较高;计算获得的锆石饱和温度为808.69~815.52℃;稀土元素总量较低,具有四分组效应和明显负δEu异常特点;富集Rb、U、Th、Nd、Hf等微量元素,亏损Ba、K、Sr、P、Ti等。以上特征均表明,花岗斑岩具有高分异A型花岗岩的特点,花岗斑岩中锆石的ω(Ce^(4+))/ω(Ce^(3+))值(1.0~29.3)较低。综合分析得出,安乐花岗斑岩具有高演化和低氧逸度特征,对Sn成矿极为有利。The Anle tin-based polymetallic deposit is located in the northwest metallogenic sub area of the southwest block of the Huanggangliang-Mengentaolegai Sn-Fe bearing polymetallic mineralization zone in the southern part of the Great Xing'an Range.The medium-sized deposit is rich in tins.The diagenetic age,petrogenesis,metallogenetic significance and geodynamic background of the rocks remains obscure.Taking the granite porphyry from Anle tin-based polymetallic deposit as the research object,the LA-ICP-MS zircon U-Pb method was used to determine the age of the granite porphyry related to the mineralization,resulting in(144±2.6)Ma(MSWD=3.2),which is basically consis-tent with the range of diagenetic age of other tin-based polymetallic ore bodies in the region,indicating that the grani-tic rocks related to tin mineralization in the southern Great Xing'an Range were mainly formed in the early Cretaceous.The geochemical characteristics of major,trace and rare earth elements show that the granite porphyry contained highω(SiO_(2))(ranging from 75.76%to 76.67%),at ratio ofω(FeO T)/ω(FeO T+MgO)ranged 0.9~1.0,ratio ofω(FeO T)/ω(MgO)ranged 18.42~20.79,ω(Ga)×10^(4)/ω(Al)ranged 3.36~4.61,0.06%~0.07%ω(MgO),0.05%~0.06%ω(TiO_(2))and 0.01%ω(P_(2)O_(5)).The zircon saturation temperature was calculated at 808.69~815.52℃.The low total rare earth content was characterized by tetrad effect and obviously unusual negativeδEu.The trace elements like Rb,U,Th,Nd,Hf were enriched,while elements like Ba,K,Sr,P,Ti were deficit.All the above indicate that the granite porphyry has the characteristics of high fractionated A-type granite,and the zircons contained in the granite porphyry have lowω(Ce^(4+))/ω(Ce^(3+))value(1.0~29.3).The results of comprehensive study show that the Anle granite porphyry is characterized by high evolution and low oxygen fugacity,which is absolutely favorable for tin mineralization.

关 键 词：多金属矿床 花岗斑岩 成矿 矿床 大兴安岭 成岩年龄 稀土元素 

分 类 号：P597[天文地球—地球化学] P611[天文地球—地质学]