摘要
党坝稀有金属矿床是近年来新发现的超大型花岗伟晶岩型稀有金属矿床,矿区内分布有北带、中带和南带含矿伟晶岩脉,其中中带研究程度相对较低,为厘清中带伟晶岩的形成时代和成矿地质意义,对其进行了详细的野外地质调查,并运用激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)对其中的铌钽铁矿进行了U-Pb定年分析。野外调查发现,中带伟晶岩侵位于三叠系侏倭组变沉积岩中,其中的北西-南东向裂隙是主要的控矿构造,含矿伟晶岩主要呈脉状产出,属钠长石锂辉石伟晶岩。等离子质谱分析得到中带Ⅵ号伟晶岩矿体产出的铌钽铁矿的^(206)Pb/^(238)U加权平均年龄为(213.5±1.2)Ma。该年龄与北带的Ⅷ号矿体年龄基本一致,均为晚三叠世。研究认为,党坝矿床伟晶岩的成矿时代与松潘-甘孜造山带其他含稀有金属伟晶岩的成矿时代一致,而且都形成于造山期后相对稳定阶段。可尔因矿田西康群中的侏倭组,是寻找稀有金属伟晶岩的首要目标地层。
The super-large Dangba deposit is a recently discovered pegmatite-type rare metal deposit,which includes the north,the central and the south zones of pegmatites.In order to explore the ore-forming age and metallogenic geological significance of the central zone pegmatite which was relative limitedly researched,based on the detailed field geological investigation,we have conducted the U-Pb dating of columbite-tantalite by using the Laser Ablation Inductively Coupled Plasma Mass Spectrometer(LA-ICP-MS)in this paper.The results indicate that the central zone lithium-bearing pegmatites,which intruded into meta-sedimentary rocks of the Upper Triassic Zhuwo Formation in the NW-SE direction ore-controlling fractures,occurred mainly as lenticular veins of the albite spodumene pegmatite.The columbite-tantalite from the No.VI lithium pegmatite vein in the central zone has weighted mean ^(206)Pb/^(238)U age of(213.5±1.2)Ma,which is basically consistant to the crystallization age of the No.VIII pegmatite vein in the north zone.They were both formed in the Late Triassic.The research results show that pegmatites of the Dangba and other rare metal deposits in the Songpan-Ganzêorogenic belt have similar metallogenic ages and they were formed in the post-collisional relatively stable tectonic settings.The Zhuwo Formation of the Xikang Group in the Ke’eryin orefield is the primary target stratum for searching for rare metal-bearing pegmatites.
作者
朱汇派
费光春
谭华
蔡云华
陈治坪
罗小龙
袁彦伟
李天瑞
ZHU Hui-pai;FEI Guang-chun;TAN Hua;CAI Yun-hua;CHEN Zhi-ping;LUO Xiao-long;YUAN Yan-wei;LI Tian-rui(Geochemistry Exploration Team of the Sichuan Bureau of Geology and Mineral Resources,Deyang,Sichuan 618000,China;College of Earth Science,Chengdu University of Technology,Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation,Ministry of Natural Resources,Chengdu 610059,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2023年第2期350-359,共10页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金资助项目(41702074)
四川省科技厅应用基础研究项目(2021yj0309)
四川省地质调查研究院科研项目(HTKY2022005)。
