甘肃公婆泉铜矿床含矿斑岩体地球化学特征、锆石U-Pb年龄及Hf同位素特征研究  

Geochemical Characteristics,Zircon U-Pb ages and Hf Isotopic Characteristics of the Ore-bearing Porphyry in the Gongpoquan Copper Deposit

作　　者：于明杰[1] 毛启贵[2,3] 方同辉[2,3] 黄行凯[2,3] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]北京矿产地质研究院,北京100012 [3]有色金属矿产地质调查中心,北京100012

出　　处：《地质与勘探》2014年第1期145-155,共11页Geology and Exploration

基　　金："十二五"国家科技支撑项目(2011BAB06B04)资助

摘　　要：甘肃公婆泉铜矿是我国西北地区一个非常重要的斑岩型铜矿床,矿体主要产在花岗闪长斑岩和英安斑岩体内。地球化学特征上,这两种斑岩的主量元素表现为低铝、高钾、高碱,微量元素以富集大离子亲石元素(LILE),如Rb、Ba、Th、Sr等元素,亏损高场强元素(HFSE),如Nb、Ta等元素为特征,具有较为明显的Eu负异常。锆石Hf同位素研究显示,本区花岗闪长斑岩的锆石εHf(t)值为4.7～8.2,单阶段Hf模式年龄(t DM1)为714～857Ma,平均为791Ma;二阶段模式年龄(t DM2)的变化范围为887～1113Ma,平均为1003Ma,显示幔源特征。利用LA-ICP-MS锆石U-Pb年代学方法,测得花岗闪长斑岩的年龄为453.2±6.5Ma,为晚奥陶世,代表了公婆泉铜矿花岗闪长斑岩的成岩结晶时代。花岗闪长斑岩的结晶时间为晚奥陶世,因此认为,公婆泉铜矿的成矿时代为晚奥陶世。The Gongpoquan copper deposit is a very important copper deposit in northwest China. The ore bodies in this deposit are mainly hosted in granodiorite porphyry and daeite porphyry. The two kinds of ore-bearing porphyry are characterized by low values of A1, high values of K20, high abun- dance of LILE, such as Rb, Ba., Th, and Sr, and low abundances of HFSE, such as Nb, and Ta. The chondrite-normalized ]REE patterns show strong negative Eu anomalies. The granodiorite porphyry is dated 453.2 ＋ 6.5Ma by the zircon LA-1CP-MS U-Pb method. The zircon Hf isotope study shows the Hf（t） values of the granodiorite porphyry are 4.7 -8.2, tDM1 714 -857Ma, t-DM2 887 - 1113Ma, Hf model age of the first stage （tom1 ） is 791 Ma and the age of the second stage （tom2 ） is 1003 Ma. In this study, the age of the granodiorite porphyry is the late Ordovician. It is suggested that the mineralo- genetic age of the Gongpoquan copper deposit is the late Ordovician.

关 键 词：公婆泉铜矿含矿斑岩 锆石U-PB Hf同位素LA-ICP-MS 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]