桂西上二叠统合山组锂超常富集黏土岩的物源分析与地质意义  

Provenance analysis and geological significance of Li-rich claystone in Upper Permian Heshan Formation,western Guangxi

作　　者：梁航 温淑女 姚双秋 黎家龙 许箭琪 徐海棚 庞保成[1,2,3] 庞崇进[1,2,3] LIANG Hang;WEN Shu-nyu;YAO Shuang-qiu;LI Jia-long;XU Jian-qi;XU Hai-peng;PANG Bao-cheng;PANG Chong-jin(Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration,Guilin University of Technology,Guilin 541006,China;Guangxi Aluminum Resources Advanced Exploration Technology and Green Mine Construction Engineering Research Center,Guilin University of Technology,Guilin 541006,China;Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources by the Province and Ministry,Guilin University of Technology,Guilin 541006,China;No.274 Geological Team of Guangxi Zhuang Autonomous Region,Beihai 536005,China)

机构地区：[1]桂林理工大学广西隐伏金属矿产勘查重点实验室,广西桂林541006 [2]桂林理工大学广西铝资源先进勘探技术及绿色矿山建设工程研究中心,广西桂林541006 [3]桂林理工大学有色金属矿产勘查与资源高效利用省部共建协同创新中心,广西桂林541006 [4]广西壮族自治区二七四地质队,广西北海536005

出　　处：《桂林理工大学学报》2022年第3期535-548,共14页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(41973014;41803020);广西自然科学基金项目(2018GXNSFAA050041);有色及贵金属隐伏矿床勘查教育部工程研究中心项目(2018GCZX001);广西壮族自治区地质矿产勘查开发局2021年部门预算前期地质勘查项目。

摘　　要：以桂西平果地区上二叠统合山组铁铝岩、富锂黏土岩为研究对象,运用(MC-)LA-ICP-MS对样品进行碎屑锆石U-Pb定年和原位Hf同位素组成分析,结合铁铝岩碎屑锆石年龄特征,揭示富锂黏土岩的碎屑物质来源。铁铝岩样品,碎屑锆石主要年龄峰值为~430 Ma,次要峰值为~258 Ma;富锂黏土岩样品(主要化学成分为SiO_(2)30.5%、 Al_(2)O_(3) 34.2%、 Fe_(2)O_(3)^(T)15.2%、 Li 981×10^(-6)),碎屑锆石呈单一年龄峰值(~258 Ma),对应的ε_(Hf)(t)为-9.7~+11.4,与岛弧岩浆锆石ε_(Hf)(t)组成类似,表明其物源主要为古特提斯二叠纪岩浆弧相关的酸性岩。桂西地区铝土矿在时空上物源存在差异,反映了岩相古地理格局对成矿起重要控制作用。The detrital zircon U-Pb dating and in situ Hf isotopic compositions were analysed using(MC-)LAICP-MS on the ferrallite and Li-rich claystone of the Upper Permian Heshan Formation in Pingguo,western Guangxi.Together with available detrital zircon U-Pb ages of ferrallite,this study reveals the provenance of the Li-rich claystone.Analytical results show that the U-Pb ages of detrital zircons from ferrallite are mainly concentrated at~430 Ma,along with a subordinate peak at~258 Ma.In contrast,the Li-rich claystone(with chemical compositions of SiO_(2)30.5%,Al_(2)O_(3)34.2%,Fe_(2)O_(3)^(T)15.2%,Li 981×10^(-6))shows the age peak at~258 Ma,with corresponding zircon ε_(Hf)(t)of-9.7 to+11.4,which are similar to those of island arc magma-derived zircons.This indicates that the Li-rich claystone was mainly sourced from the Permian felsic igneous rocks related to Paleo-Tethys arc magmatism.Tempo-spatial variations of provenances of bauxite-bearing rocks of the Heshan Formation suggest that paleogeographic variations play an important role in the formation of bauxite in western Guangxi.

关 键 词：铝土矿 富锂黏土岩 物源 碎屑锆石 U-PB年龄 HF同位素 合山组 广西 

分 类 号：P618.71[天文地球—矿床学] P588.22[天文地球—地质学] P597.3