塔里木大火成岩省碱性岩浆活动与稀有金属成矿作用  

Alkaline Magmatism and Associated Rare-metal Mineralization in the Tarim Large Igneous Province

作　　者：朱圣柱 黄小龙[1,2,3] 于洋 贺鹏丽[1,2,3] 杨帆[1,2,3] 李梦静 ZHU Shengzhu;HUANG Xiaolong;YU Yang;HE Pengli;YANG Fan;LI Mengjing(State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Center of Excellence of Deep Earth Sciences,Guangzhou 510640,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州地球化学研究所,同位素地球化学国家重点实验室,广东广州510640 [2]中国科学院深地科学卓越研究中心,广东广州510640 [3]南方海洋科学与工程广东省实验室(广州),广东广州511458 [4]中国科学院大学,北京100049

出　　处：《大地构造与成矿学》2023年第3期631-660,共30页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(42021002、41625007);中国科学院战略性先导科技专项(B类)(XDB18000000);南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0202)联合资助。

摘　　要：地幔柱活动导致大火成岩省的形成,并伴随大规模岩浆作用和成矿事件。碱性岩型稀有金属矿床是地幔柱成矿作用中非常重要的一类,但目前对该类矿床形成过程中稀有金属元素超常富集机制仍缺少系统性研究。本文搜集了塔里木大火成岩省两大构造域(塔里木克拉通及边缘地区和中亚造山带)碱性岩浆岩的年代学和岩石地球化学数据,分析其岩浆活动和成矿作用的基本特点,探讨地幔柱与不同类型大陆岩石圈相互作用导致稀有金属元素富集的差异性。塔里木克拉通及边缘地区碱性岩浆岩主要为碱性正长岩‒花岗岩和碳酸岩,形成于291~268 Ma,峰期年龄为~278 Ma,主要属于塔里木大火成岩省最晚阶段的岩浆活动;其中碱性正长岩‒花岗岩富碱、Th、REE、Nb、Zr,高Ga/Al、Nb/Ta值,多数显示典型A1型花岗岩的地球化学特征。中亚造山带碱性岩浆岩为碱性正长岩‒花岗岩,形成于325~255 Ma,大部分与塔里木大火成岩省岩浆活动时代一致,其碱、Th、REE、Nb、Zr含量和Ga/Al、Nb/Ta值明显低于塔里木克拉通及边缘地区的碱性正长岩‒花岗岩,并且多数显示典型A2型花岗岩的地球化学特征。塔里木克拉通及边缘地区的碱性正长岩‒花岗岩和碳酸岩赋存Nb-Zr-REE矿床,而中亚造山带的碱性正长岩‒花岗岩则赋存Li-Be-Ta-Nb-W-Sn-Mo矿床。地幔柱和再循环洋壳物质加入地幔源区导致塔里木克拉通及边缘地区的碱性岩浆岩富集Nb、Zr、REE;中亚造山带碱性岩浆岩的源区因近期俯冲交代影响的岩石圈地幔和新生地壳物质的参与而显著富集Li、Be、W、Sn、Mo等流体活动元素。塔里木克拉通及边缘地区碱性正长岩‒花岗岩贫硅、钠质、过碱性的特征有利于熔体中Nb、Zr、REE的富集;而中亚造山带碱性正长岩‒花岗岩富硅、钾质、过铝质的特征有利于Ta、Li、W、Sn的富集。塔里木克拉通和中亚造山带具有不Mantle plume causes the formation of Large Igneous Province(LIP),which is usually accompanied by extensive magmatism and mineralization.Rare-metal deposits hosted in the alkaline igneous rocks is one of the most important mineralization types related to mantle plume activities.However,systematic investigations on the mechanism of the extreme enrichment of rare-metals during the formation of rare-metal deposits are still insufficient.In this paper,we compiled the published geochronological and geochemical results of the Late Carboniferous-Permian alkaline igneous rocks from the Tarim Craton and the Central Asian Orogenic Belt(CAOB)in the Tarim LIP(TLIP),with aims to investigate the nature of these alkaline magmatism and associated mineralization,to explore the enrichment mechanism of rare-metals in the different mantle plume-continental lithosphere interactions.Alkaline igneous rocks in the Tarim Craton and its margin are mainly alkaline syenitic-granitic rocks and carbonatites,which were formed at 291 Ma to 268 Ma,with a peak age at ca.278 Ma,and mainly belong to the latest magmatism in the TLIP.Alkaline syenitic-granitic rocks in the Tarim Craton and its margin have high alkali,Th,REE,Nb,Zr contents with high Ga/Al and Nb/Ta ratios,and most of them have geochemical features resemble those of the typical A1-type granite.Alkaline igneous rocks in the CAOB are alkaline syenitic-granitic rocks,which were formed at 325 Ma to 255 Ma,and most of them are coeval to the TLIP.These rocks have significantly lower alkali,Th,REEs,Nb,Zr contents and show Ga/Al and Nb/Ta ratios lower than the alkaline igneous rocks in the Tarim Craton and its margin,and are similar to the typical A2-type granite in their geochemical features.Alkaline igneous rocks in the Tarim Craton and its margin usually host Nb-Zr-REE deposits,while the CAOB alkaline igneous rocks host Li-Be-Ta-Nb-W-Sn-Mo deposits.Inputs of plume materials and recycled oceanic crust in mantle source beneath the Tarim Craton and its margin led to the enrichment of Nb,Zr and

关 键 词：碱性岩浆岩 稀有金属成矿 地幔柱‒岩石圈相互作用 塔里木大火成岩省 中亚造山带 

分 类 号：P588.1[天文地球—岩石学] P617[天文地球—地质学]