非洲中部新元古代Lufilian弧地区地质特征、成矿时代及构造演化历史  

Geological Characteristics,Metallogenic Age and Tectonic Evolution History of Neoproterozoic Lufilian Arc in Central Africa

作　　者：许康康 孙凯 何胜飞 龚鹏辉 张航 卢宜冠 XU Kangkang;SUN Kai;HE Shengfei;GONG Penghui;ZHANG Hang;LU Yiguan(Tianjin Centre,China Geological Survey(CGS),Tianjin 300170;North China Center of Geoscience Innovation,Tianjin 300170)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]华北地质科技创新中心,天津300170

出　　处：《地质与勘探》2021年第3期676-692,共17页Geology and Exploration

基　　金：中国地质调查局项目(编号:DD20190439);商务部援外项目(批件号:[2015]352)资助

摘　　要：研究非洲中部新元古代Lufilian弧的地质矿产特征和构造演化历史,对深入了解前寒武纪地壳演化和成矿作用具有重要的意义。本文在系统收集Lufilian弧内地层、岩浆岩、变质、变形和成矿作用的基础上,对该带的构造演化历史进行了总结概括。研究表明:Lufilian弧基底为一条古元古代弧岩浆作用带,约880 Ma,Lufilian弧开始了早期的陆内裂谷作用,发育恩昌加花岗岩和早期基性岩浆作用,并沉积有罗安群地层。约765 Ma,裂谷作用演化至原始大洋裂谷阶段,罗安群沉积结束并开始沉积恩古巴群早期地层,在成岩期热液流体作用下形成了同沉积阶段铜钴、铀和铅锌矿化作用。至660 Ma左右,开始了早期的洋壳俯冲作用,并沉积有恩古巴群晚期碎屑地层。550 Ma左右,卡拉哈里克拉通与刚果克拉通发生陆-陆碰撞作用,在530 Ma左右,碰撞作用达到高峰阶段,而后期高温变质叠加作用持续到520 Ma左右,挤压作用晚阶段可能受莫桑比克洋闭合阶段近东西向远场挤压应力的影响,板块发生幕式折返作用,形成Hook岩基。约520~470 Ma,为变质岩石抬升冷却阶段。在同构造和构造后期,在变质热液流体作用下,早期矿物再次活化,在构造有利部位形成矿体。The study of the geological and mineral characteristics and tectonic evolution history of Neoproterozoic Lufilian Arc in Central Africa is of great significance for further understanding of the Pre-Cambrian crustal evolution and mineralization.Based on the systematic collection of strata,magmatic rocks,metamorphism and deformation events and mineralization,this paper summarizes the tectonic evolution history of the Lufilian Arc.The result shows that the basement in Lufilian Arc is a Paleoproterozoic arc magmatism zone.At about 880 Ma,when the intracontinental rifting started,Nchanga granite and the early mafic magmatism were developed,and Roan Group began to deposit.At about 765 Ma,the rifting process evolved to the stage of proto-ocean rift,the deposition of Roan Group ended and the early Nguba Group began to deposit;under the influence of hydrothermal fluids in the diagenesis period,the co-sedimentary copper,cobalt,uranium,lead and zinc mineralizations were formed.At about 660 Ma,when the early oceanic crust subduction started,the late clastic strata of Nguba Group began to deposit.At about 550 Ma,the continental collision between the Kalahari Craton and Congo Craton started and reached its peak stage at about 530 Ma,and the temperature peak of the metamorphic overprint in the stage was continued to about 520 Ma.At the late stage,the subduction slab retreated by the influence of nearly E-W far-field compression stress during the closure of Mozambique Ocean and formed Hook Batholith.From 520 Ma to 470 Ma,the metamorphic rocks were exhumated and cooled.Under the influence of metamorphic hydrothermal fluid at the stages of syn-and post-tectonic,the early mineralization was remobilizated,forming ore bodies in favourable parts of structure.

关 键 词：地层 岩浆岩 变质、变形作用 矿化作用 构造演化 Lufilian弧 中非 

分 类 号：P612[天文地球—矿床学]