智利月亮山地区中生代侵入岩成因及其构造意义:来自锆石U-Pb年代学、岩石地球化学的制约  

Origin of the Mesozoic intrusions in the Sierra de la Luna,Chile:Evidence from zircon U-Pb dating and geochemistry

作　　者：王磊[1] 方维萱[1] 鲁佳[1] 杜斌 WANG Lei;FANG Weixuan;LU Jia;DU Bin(China Non-Ferrous Metals Resource Geological Survey,Beijing 100012,China)

机构地区：[1]有色金属矿产地质调查中心,北京100012

出　　处：《矿产勘查》2024年第10期1858-1868,共11页Mineral Exploration

基　　金：科技部科研院所技术开发研究专项项目(2011EG115022)资助。

摘　　要：月亮山铁铜矿区处于智利中北部海岸山带铁氧化物铜金矿(IOCG)成矿带上,位于一级控矿构造阿塔卡玛(ATACAMA)断裂带的南缘。全岩地球化学研究表明,本区二长闪长岩性质具有钙碱性、准铝质特征,其La/Nb比值大于1.5,La/Ta比值大于22,微量元素图显示均显著亏损Nb、Ta和Ti,表明二长闪长岩岩浆的源区起源于与俯冲相关的岩石圈地幔。二长闪长岩的LA-ICP-MS锆石U-Pb年龄为(108.2±1.9)Ma,表明其为早白垩世晚期的岩浆活动的产物。构造环境分析表明,太平洋纳斯卡板块向南美板块俯冲过程中,形成本区南北向的ATACAMA断裂带(AFZ)与母岩浆,深层岩浆侵位经过部分熔融、结晶分异过程形成了闪长岩岩体,与本区IOCG矿床的形成关系密切。The Sierra de la Luna iron-copper deposit is located in the IOCG(Iron Oxide Copper Gold)metal-logenic belt of the coastal mountain belt in the central-northern part of Chile,and on the southern edge of the primary controlling structural Atacama fault zone.Magmatic activities are frequent in the area,and the intrusive rocks are mainly diorite in this area.According to this study,the diorite in this area possesses quasi-aluminous and calcium alkaline geochemical features.The La/Nb ratio in diorite is greater than 1.5,and the La/Ta ratio is greater than 22.The trace element map shows significant depletion of Nb,Ta and Ti,indicating that the source area of diorite magma originated from the lithospheric mantle associated with subduction.The LA-ICP-MS zircon U-Pb age of diorite is(108.2±1.9)Ma,indicating that it is a product of magmatic activity in the late Early Cretaceous.Structural environment analysis shows that the north-south trending AFZ(Atacama Fault Zone)and the parental magma were formed during the subduction of the Pacific Nazca Plate beneath the South American Plate.The deep-seated intrusions of diorite formed through partial melting and crystal fractionation processes are closely related to the formation of IOCG deposits in this area.

关 键 词：岩浆源区 形成机制 铁氧化物铜金矿 二长闪长岩 智利 

分 类 号：P624.6[天文地球—地质矿产勘探] P597.3[天文地球—地质学]