中国首例太古宙LCT型矿化伟晶岩——鲁中雁翎关锂辉石伟晶岩的发现及意义  

The first LCT-type mineralized pegmatite in China:Discovery and significance of Yanlingguan spodumene pegmatite in central Shandong

作　　者：李鹏 李建康[1] 刘秦龙 王登红[1] 姜鹏飞 覃海宝 LI Peng;LI JianKang;LIU QinLong;WANG DengHong;JIANG PengFei;QIN HaiBao(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;College of Earth Sciences,Hebei GEO University,Shijiazhuang 050031,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037 [2]河北地质大学地球科学学院,石家庄050031

出　　处：《岩石学报》2024年第9期2621-2637,共17页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42330806、42002109、41872096);中国地质调查项目(DD20230034、DD20230289、DD20243484);中国地质科学院基本科研业务费重点项目(JKYZD202315)联合资助。

摘　　要：新太古代是地球演化历史上的重要时期,众多克拉通完成聚合并趋于成熟稳定,在此过程中广泛的陆块拼合及碰撞造山事件,形成了世界范围的稀有金属成矿作用高峰。我国的稀有金属成矿事件主要集中于显生宙,未见太古宙LCT型矿化伟晶岩的报道。本文第一作者所在的研究团队通过建立中国稀有金属伟晶岩的成矿谱系,厘定了大地构造演化与稀有金属成矿的关系,提出华北克拉通在我国具有产出太古宙伟晶岩的最佳条件。通过详细的野外地质勘查,我们在鲁中雁翎关地区首次发现了我国太古宙LCT型(Li-Cs-Ta)矿化伟晶岩。铌钽铁矿原位U-Pb定年结果显示,雁翎关伟晶岩经历了2609.0±13.0Ma和2501.6±8.6Ma两阶段成矿事件。其中,2609Ma成矿事件与华北克拉通东部块体雁翎关绿岩带的形成时代对应,2502Ma成矿事件则对应了与华北陆块克拉通化有关的大规模壳熔花岗岩事件。矿物学研究表明,雁翎关矿床伟晶岩中锂辉石Li_(2)O为7.66%~7.93%,接近锂辉石中Li_(2)O的理论上限,为高品质锂资源。同时伟晶岩还含有锂电气石、富Cs长石、钽锰矿和磷灰石,是典型的LCT型伟晶岩。相比于国内外同类型矿床,雁翎关伟晶岩结晶温压条件较高,故无透锂长石产出。~2.50Ga华北克拉通频繁的陆-陆碰撞作用,伴随了多期次的岩浆活动,为太古宙基底的渐进式部分熔融创造了持续的热供给,为稀有金属元素的超常富集及LCT型伟晶岩的形成提供了理想的条件。“富陆源组分基底+微陆块构造带”可作为华北克拉通伟晶岩型稀有金属资源的重要找矿标志。The Neoarchean was an important period in the evolution history of the Earth,when cratons completed aggregation and tended to stabilize.During this process,the large-scale accumulations of microcontinents and accompanying collision orogenic events formed a global peak of rare-metal mineralization.However,rare-metal mineralization events in China are mainly occurred in Phanerozoic,with few reports of Archean mineralization events.By establishing the metallogenic pedigree of rare metal pegmatites in China and combing the relationship between tectonic evolution and rare metal mineralization,we propose that the North China Craton has the best conditions for producing Archean pegmatites in China.Through detailed field investigation,we have discovered the Archean LCT type(Li-Cs-Ta)mineralized pegmatite in China for the first time in Yanlingguan area of central Shandong Province.Through the columbite-tantalite U-Pb dating,the two-stage Li-Nb-Ta metallogenic events in the Archean 2609.0±13.0Ma and 2501.6±8.6Ma in North China have been accurately determined.The 2609Ma mineralization event corresponds to the formation of the Yanlingguan greenstone belt in the Eastern Block of the North China Craton,while the 2502Ma mineralization event corresponds to the large-scale crust-melt granite event related to the cratonization of the North China Craton.Based on mineralogical research,the measured Li_(2)O of spodumene in the Yanlingguan pegmatite is 7.66%~7.93%,which is close to the theoretical upper limit of Li_(2)O in spodumene,and thus this pegmatite might has a high-quality lithium resource potential.The Yanlingguan pegmatite also contains elbaite,Cs-rich feldspar,manganotantalite and apatite,making it a typical LCT-type pegmatite.Compared with the same type deposits,the crystallization temperature and pressure conditions of Yanlingguan pegmatite are higher,so there is no production of petalite.The frequent continental-continental collision in the~2.50Ga North China Craton,accompanied by multi-stage magmatic activities,create

关 键 词：稀有金属 LCT型伟晶岩 太古宙 雁翎关 华北克拉通 

分 类 号：P588.131[天文地球—岩石学] P597.3[天文地球—地质学] P618.7