玻利维亚Cuprita铜矿及其周缘火山喷发-岩浆侵入构造特征与找矿预测  

Characteristics of Volcanic Eruption-magma Intrusion Related Structures and Prospecting Prediction for the Cuprita Copper Deposit and Its Surroundings,Northern Bolivia

作　　者：杜玉龙 方维萱[2] DU Yuong;FANG Weixuan(Minmetals Exploration and Development Co.,Ltd.,Beijing 100010,China;China Non-ferrous Metals Resource Geological Survey,Beijing 100012,China)

机构地区：[1]五矿勘查开发有限公司,北京100010 [2]有色金属矿产地质调查中心,北京100012

出　　处：《大地构造与成矿学》2024年第4期709-723,共15页Geotectonica et Metallogenia

基　　金：国土资源部行业性科研基金项目(201511016-1);中战会(北京)矿业科技有限公司勘查项目(2016001)联合资助。

摘　　要：玻利维亚北部火山喷发-岩浆侵入构造具有明显的成岩成矿作用。本文采用构造岩相学填图研究Cuprita铜矿及其周缘火山喷发-岩浆侵入构造组合、物质组成和控矿规律。结果显示:在Cuprita铜矿及其周缘发育渐新世-中新世火山穹窿构造与火山岩相体,叠加晚中新世岩浆侵入构造与侵入岩体,构造组合样式有火山穹隆构造-环形断裂、岩浆侵入构造-近EW向断裂、岩浆热液角砾岩筒(带)与热液角砾岩相体。从火山穹隆中心向外,火山岩相依次发育火山通道相、火山爆发相、火山溢流相、火山沉积岩相;橄榄辉长玢岩-闪长玢岩呈岩株、岩枝和岩床产出;在岩株顶部和产状突变处发育热液角砾岩相,包含6类热液角砾岩。火山穹隆构造-环形断裂控制了火山岩相-火山沉积岩相空间分布与矿床的形成、分布;岩浆侵入构造-EW向断裂控制了岩浆热液成矿作用的发生与矿体的产出;热液角砾岩相与岩浆热液角砾岩筒(带)为储矿构造岩相体与储矿构造样式。预测在Cuprita铜矿岩浆热液角砾岩筒深部和外围以寄生火山穹隆构造为中心等是有利的找矿预测区。The volcanic eruption-magma intrusion related structures in northern Bolivia have obvious controls on the occurrences of the rocks and ore mineralization.In this study,tectonic lithofacies mapping method was exploited to investigate the characteristics of the volcanic eruption-magma intrusion related structures in the Cuprita Cu deposit and its surroundings,northern Bolivia,aiming to reveal their structural association,material composition features,and constraints on Cu mineralization.The results demonstrated that the magmatic rocks within the Cuprita Cu deposit are mainly Oligocene-Miocene volcanic and extrusive rocks,overlapped by the late Miocene mafic-intermediate intrusions.Structural association styles include the volcano domes and circular faults,intrusive related structures and EW-trending faults,magmatic-hydrothermal breccia chimney and hydrothermal breccia facies.From the center of the volcanic dome to its edge,the volcanic facies transform from magmatic chamber through eruptive rocks and lava flows to volcano-sedimentary sequences.Porphyritic olivine-gabbro and dioritic porphyrite mainly occur as dikes,stocks,and sheets,with hydrothermal breccias at the top of the stocks.The breccias can be further divided into six groups:the quartz-and sulfide-bearing breccia,porphyritic breccia,basaltic-andesitic breccia,collapsed breccia,volcanic breccia,and volcano-sedimentary breccia.Our geological mapping demonstrated that the annular domes controlled the distribution of the volcanic rocks and deposits,whereas the intrusive structures and EW-trending faults controlled the occurrence of mafic-intermediate intrusions and related hydrothermal activities.Copper mineralization was further developed within the magmatic-hydrothermal breccias described above.The magmatic-hydrothermal breccias within the Oligocene-Miocene volcanic domes are therefore promising for copper exploration in the Cuprita region.

关 键 词：火山喷发‒岩浆侵入构造 构造组合 物质组成 控矿规律 找矿预测标志 玻利维亚Cuprita铜矿 

分 类 号：P613[天文地球—矿床学] P612[天文地球—地质学]