新疆阿尔泰造山带伟晶岩型稀有金属矿床成矿作用  

Pegmatite-type mineralization of rare metals in the Altai orogenic belt,Xinjiang

作　　者：陈衍景[1,2] 韩金生 CHEN Yanjing;HAN Jinsheng(Key Laboratory of Crustal and Orogenic Evolution,Peking University,Beijing 100871,China;The State 305 Project Office of the People's Government of Xinjiang Uygur Autonomous Region,Urumqi,Xinjiang 830000,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China)

机构地区：[1]北京大学造山带与地壳演化重点实验室,北京100871 [2]新疆维吾尔自治区人民政府国家305项目办公室,新疆乌鲁木齐830000 [3]中国地质大学(武汉)资源学院,湖北武汉430074

出　　处：《地质学报》2024年第5期1452-1472,共21页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42173068);新疆维吾尔自治区重点科技研发项目(编号2023B03015);国家305项目办公室“天池英才”引进计划联合资助的成果。

摘　　要：花岗伟晶岩与稀有金属(Li、Be、Nb、Ta等)矿床关系密切。关于伟晶岩成矿模式、伟晶岩与花岗岩之间的成因关系等,已有大量研究和讨论,但仍然存在争议。新疆阿尔泰是我国著名的伟晶岩及稀有金属矿床集中区,研究资料丰富。本文系统分析了阿尔泰伟晶岩的地质背景与成矿地质特征,阐明阿尔泰造山带伟晶岩与花岗岩存在3种关系:(1)缺乏成因联系,伟晶岩可能为变质脱水熔融形成的独立伟晶岩;(2)可能为“兄弟关系”;(3)可能为“母子关系”,共同构成花岗岩-伟晶岩成岩成矿系统。作者提出一个包含多种成因伟晶岩的成岩成矿构造模式,可能在矿带、矿田、矿床尺度上都适用。阿尔泰造山带稀有金属伟晶岩成矿省的形成受到古生代地层的控制。阿尔泰造山带处于典型的幔坡带,为长期活跃的构造活动带,极易受到外部构造域的干扰,在晚三叠纪受到特提斯构造域的一系列陆块向北漂移并拼贴到欧亚大陆南缘的远程效应影响而发生大规模的稀有金属成矿作用,在侏罗纪,其构造活动及成岩成矿作用则受新特提斯构造域和蒙古-鄂霍茨克洋构造域地质作用的远程效应共同影响。Granitic pegmatites are intimately associated with rare-metal mineralization(e.g.,Li,Be,Nb,and Ta).Despite extensive research and discussion surrounding the metallogenic model of pegmatites and their genetic relationship with granites,certain controversies remain unresolved.The Altai orogenic belt in northern Xinjiang,renowned for its abundance of well-studied pegmatite-type rare-metal deposits,provides a valuable case study for addressing these complexities.This paper presents a systematic synthesis of the geological background and metallogenic characteristics of the Altai pegmatites.We delineate three distinct genetic relationships between pegmatites and granites in the Altai orogenic belt:①Pegmatites derived from independent pegmatitic melts via anataxis,showing no genetic connection with granites;②Pegmatites exhibiting coeval and proximal origins with granite,suggesting a shared magmatic ancestry;③Pegmatites that represent derivative products of parental granitic magmas,both components integrated within a granite-pegmatite magmatic system.Meanwhile,we propose a petrogenetic-metallogenic model for the pegmatite in the region and speculate that pegmatites of different genetic styles may coexist at provincial,orefield,and deposit scales.The formation of the Altai pegmatite-type rare metal province was influenced by the presence of Paleozoic sedimentary rocks.In addition,the Altai orogenic belt,located in a mantle slope zone,exhibits susceptibility to far-field impacts from external tectonic events.In the Triassic,the formation of rare metal-bearing pegmatites was triggered by the far-field impact of the northward-directed accretion of terranes formerly associated with the Gondwana Land(Tethys tectonic domain)onto the southern margin of Eurasia.In the Jurassic,the tectonic framework,petrogenesis,and mineralization in the Chinese Altai were collectively influenced by the far-field effects of the Neo-Tethys and the Mongolia-Okhotsk Ocean tectonic events.

关 键 词：稀有金属 伟晶岩 花岗岩 阿尔泰造山带 伟晶岩成岩成矿构造模式 远程效应 

分 类 号：P618.6[天文地球—矿床学]