赣南中生代海罗岭稀有金属矿床成因--基于云母微量元素的研究  

Genesis of the Mesozoic Hailuoling granite-pegmatite rare-metal deposit in southern Jiangxi Province—based on the trace-element study in

作　　者：许箭琪 郭春丽[1,3] 闫金禹 张斌武 赵迁迁 周睿[4] XU Jianqi;GUO Chuni;YAN Jinyu;ZHANG Binwu;ZHAO Qianqian;ZHOU Rui(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,Anhui,China;SinoProbe Laboratory,Chinese Academy of Geo-logical Sciences,Beijing 100094,China;China University of Geosciences(Beijing),Beijing 100037,China)

机构地区：[1]自然资源部成矿作用与资源评价重点实验室,中国地质科学院矿产资源研究所,北京100037 [2]合肥工业大学资源与环境工程学院,安徽合肥230009 [3]自然资源部深地科学与探测技术实验室,中国地质科学院,北京100094 [4]中国地质大学(北京),北京100083

出　　处：《华东地质》2025年第1期33-54,共22页East China Geology

基　　金：国家自然科学基金“南岭‘东钨西锡’空间规律的关键制约因素:基于精细矿物学对岩浆过程差异性的研究(编号:92162210)”和“南岭锡田印支期与燕山期花岗岩钨锡成矿能力的差异性(编号:42172096)”项目联合资助

摘　　要：位于赣南石城县的海罗岭矿床是一个形成于中生代的花岗伟晶岩型Nb-Ta多金属矿床,以往研究大多关注该矿床的地质特征而未阐明其成因机制。文章通过电子探针(EPMA)和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)测试技术,对矿床中细粒钠长石化花岗岩、云英岩化花岗岩、云英岩和伟晶岩中的各类型云母进行分析,发现细粒钠长石化花岗岩中的云母主要是锂云母和铁锂云母,云英岩化花岗岩和云英岩中的云母主要是黑鳞云母,伟晶岩中的云母主要是铁锂云母和黑鳞云母,它们并未按照花岗岩→云英岩化花岗岩→云英岩→伟晶岩序列中云母的锂含量逐步升高的顺序演化。而且,与云英岩化花岗岩和云英岩相比,细粒钠长石化花岗岩中云母的Rb、Li、F含量更高,但K/Rb值却更低,可能为同源岩浆经历了更高分异程度的产物。伟晶岩中出现的似筛状结构表明其经历了早期慢速成核和晚期快速冷却的转变过程。通过与新疆可可托海稀有金属矿床的地质特征和伟晶岩矿物学特征进行对比,推测两者具有相似的成因,均经历了以熔体为主的结晶分异、流体出溶和熔体-流体共存阶段。在熔体-流体共存体系脱离岩浆房上侵的过程中,某些矿物经历缓慢结晶而发生快速冷却、固结,形成了这种远离岩浆房且各种岩性混杂堆积的花岗伟晶岩型矿床。The Hailuoling deposit,which is located in Shicheng County,southern Jiangxi,is a granitic peg-matite-type Nb-Ta-Zr-W-Sn-Li-Rb polymetallic deposit formed in the Mesozoic.Previous studies have focused on the geological characteristics of the deposit,but have not elucidated its formation mechanism yet.This re-search analyzed the micas in the fine-grained albite granite,greisenized granite,greisen,and pegmatite in the Hailuoling deposit by electron probe microanalysis(EPMA)and laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).The results show that micas in the fine-grained albite granite are dominated by lepi-dolite and zinnwaldite.In greisenized granite and greisen,micas are composed of protolithionite.The micas in pegmatite are mainly zinnwaldite and protolithionite.These rocks did not evolve according to the order of gradual increase of lithium content from granite→greisenized granite→greisen→pegmatite.Furthermore,compared to the greisenized granite and greisen,the micas in the fine-grained albite granite contain higher Rb,Li,and F but a lower K/Rb ratio.The regularity of major and trace elements possibly indicates a product of a more intense frac-tionation process of the same magmatic source.The sieve-like textures in the pegmatite suggested that the deposit experienced a transition from slow nucleation in the early stage to rapid undercooling in the later stage.By com-paring the characteristics of the deposits and minerals in pegmatite between Hailuoling deposit and Koktokay de-posit,it is inferred that the two deposits have similar ore-forming mechanism.Both of them experienced crystal fractionation dominated by melts,fluid exsolution,and the coexistence of melts and fluids.Some minerals crystal-lized under slow undercooling and solidified under rapid cooling conditions during the emplacement of the melt-fluid coexistence system,forming the granitic pegmatite-type deposit far away from the magma chamber and characterized with a mixture of various rock types.

关 键 词：稀有金属矿床 花岗伟晶岩型 云母微量元素 海罗岭 可可托海 赣南 

分 类 号：P611[天文地球—矿床学] P618.79[天文地球—地质学] P618.86