地球学报2026，Vol.47Issue(3)：644-666,23.DOI:10.3975/cagsb.2025.072221
柴北缘茶卡北山成矿带含铍与富锂花岗伟晶岩中磷灰石年龄、原位地球化学特征及其地质意义
Ages,In-situ Geochemical Characteristics,and Its Geological Significance of Apatite in Be-bearing and Li-rich Granitic Pegmatites from the Chakabeishan Metallogenic Belt,Northern Qaidam Basin
摘要
Abstract
Apatite is an effective"black box"of magmatic and hydrothermal processes owing to its strong stability and diversiform components.The recently discovered Chakabeishan lithium-beryllium metallogenic belt is a granitic pegmatite-type rare-metal belt.However,no granite relevant to pegmatite has been found in the eastern part of the Zongwulong tectonic zone,where the Chakabeishan metallogenic belt is located.Moreover,the accurate emplacement age,detailed magmatic processes,and genetic mechanisms of granitic pegmatites need to be studied in depth.In this study,primary magmatic apatite from beryllium-bearing granitic pegmatites in the Chakabeishan ore block and lithium-rich granitic pegmatites in the Edanggang ore block were selected for in-situ U-Pb dating and major and minor element analyses.The Electron Probe X-ray Micro-Analyzer analysis results show that the apatite in beryllium-bearing and lithium-rich granitic pegmatites is fluorapatite,with average F contents of 3.86%and 3.81%,Cl contents of 0.01%or below the detection limit,high FeO and MnO contents,and average Fe2+/Mn2+(pfu)values of 0.10 and 0.19,respectively.The Laser Ablation Inductively Coupled Plasma Mass Spectrometry test results show that apatite in lithium-rich pegmatite has a higher U content,lower Th/U(approximately 0.05),and lower Sr content than apatite in beryllium-bearing granitic pegmatite.The chondrite-normalized REEs distribution curves of apatite from beryllium-bearing granitic pegmatite present as right oblique lines with a positive europium anomaly,and the curves of apatite from lithium-rich pegmatite present as"M"-type with the four-grouping effect.The crystallization age of apatite in beryllium-bearing and lithium-rich granitic pegmatite was(216.29±3.14)Ma,which is the emplacement and condensation age of pegmatite.The Chakabeishan granitic pegmatite-type lithium beryllium ore belt was formed by highly evolved granitic magma originating from the partial melting of metamorphic sedimentary rocks under the background of post-collision to intra-plate extension in the Late Indosinian,and had characteristics of Li-Cs-Ta type pegmatites.Magma from the same source area formed beryllium-bearing granitic pegmatite in the Chakabeishan ore block and lithium-rich granitic pegmatite in the Edanggang ore block at different evolution stages.The water content of the magma increased and the temperature and oxygen fugacity decreased during the evolution of granitic pegmatite magma from the beryllium-bearing stage to the lithium-rich stage.关键词
柴达木盆地北缘/茶卡北山/花岗伟晶岩/锂铍矿/磷灰石/U-Pb年龄/原位地球化学/岩浆过程Key words
northern margin of Qaidam Basin/Chakabeishan/granitic pegmatite/lithium beryllium ore/apatite/U-Pb age/in situ geochemistry/magmatic process分类
天文与地球科学引用本文复制引用
康利刚,石煜,王成辉,邵恒博,兰华平,赵如意,王登红,李积清,凤永刚,李凯旋,梁婷,李善平,李正辉..柴北缘茶卡北山成矿带含铍与富锂花岗伟晶岩中磷灰石年龄、原位地球化学特征及其地质意义[J].地球学报,2026,47(3):644-666,23.基金项目
本文由国家重点研发计划项目(编号:2021YFC2901902)、中国核工业地质局项目"柴达木盆地阿拉尔-苏干湖地区铀矿资源调查评价与勘查"(编号:202219)、东华理工大学博士启动基金(编号:DHBK2019307)和中国铀业有限公司-东华理工大学核资源与环境国家重点实验室联合创新基金项目(编号:2022NRE-LH-17)联合资助. This study was supported by National Key Re-search and Development Program of China(No.2021YFC2901902),China Nuclear Industry Geologi-cal Bureau Project(No.202219),East China Univer-sity of Technology PhD Startup Fund(No.DHBK2019307),and China Uranium Co.,Ltd.-State Key Laboratory of Nuclear Resources and Environ-ment,East China University of Technology Joint In-novation Fund Project(No.2022NRE-LH-17). （编号:2021YFC2901902）
