西北地质2024，Vol.57Issue(4)：66-79,14.DOI:10.12401/j.nwg.2024044
内蒙古北山花石头山萤石矿床成因:萤石微量、稀土和H-O同位素制约
Genesis of the Huashitoushan Fluorite Deposit,Beishan,Inner Mongolia:Constraints from Trace Elements,REE and H-O Isotope Geochemistry of Fluorite
摘要
Abstract
The Huashitoushan fluorite deposit is a newly discovered fluorite deposit with medium-large poten-tial resources in the eastern part of the Beishan metallogenic belt.The orebodies are located in the outer contact zone of the Suosuojing biotite monzogranite and are controlled by NE and NS faulted structure.The host rock is mainly quartz sandstone and siltstone with limestone lens of Xishuangyingshan Formation.On the basis of studying the geological characteristics of the Huashitoushan fluorite deposit,carry out the studies of trace ele-ment,REE and H-O isotope geochemistry.The results show that 9 fluorite samples showed strong enrichment of MREE relative to LREE and HREE,and the standard partition curve showed an"inverted V"shape.Positive Eu anomaly(1.11～1.25)and negative Ce anomaly(0.90～0.95)indicate a weakly oxidizing environment with the same source of ore-forming fluids and lower temperature.In addition,the characteristics of La/Ho-Y/Ho of the fluorite samples Indicate that the ore-forming fluid may be a contemporaneous and homologous F-rich fluid.The δDV-SMOW values of the 5 fluorites ranged between-109.7‰ and-99.4‰(average value is-104.3‰),while the δ18OV-SMOW values ranged between-3.1‰ and-1.9‰(average value is-2.3‰),which indicating that the ore-forming fluid is a mixed hydrothermal solution of atmospheric water and magmatic water.The characteristics of Tb/La-Tb/Ca also indicates that the Huashitoushan fluorite deposit is magmatic hydrothermal.Moreover,only Sb in all fluorite samples is enriched compared to wall rock(Xishuangyingshan Formation,Beishan Oregenic Belt and Crustal),while other elements are depled,which indicating that the fluorite deposit belongs to the cate-gory of medium-low temperature deposits.The REE standard distribution curves of two biotite monzogranites show a right inclination,and LREE is strongly enriched relative to HREE.Combined with the geological charac-teristics of the deposit,it is believed that the Huashitoushan fluorite deposit was formed in a weakly oxidizing environment with lower temperature.The ore-forming fluid is a mixed hydrothermal solution of magmatic wa-ter and atmospheric water,the ore-forming material F is mainly derived from biotite monzogranite,and the Ca mainly comes from the Xishuangyingshan Formation.Therefore,it can be inferred that the Huashitoushan fluo-rite deposit is a medium-low-temperature hydrothermal,structure filling type deposit.关键词
萤石矿床/微量元素/稀土元素/H-O同位素/内蒙古Key words
fluorite deposit/trace elements/REE/H-O isotopes/Inner Mongolia分类
天文与地球科学引用本文复制引用
刘天航,唐卫东,高永宝,魏立勇,何佳乐,范堡程,张羽,董梦杰..内蒙古北山花石头山萤石矿床成因:萤石微量、稀土和H-O同位素制约[J].西北地质,2024,57(4):66-79,14.基金项目
陕西省自然科学基础研究计划(2023-JC-QN-0362)和中国地质调查局项目(DD20211552、DD20243052)联合资助. （2023-JC-QN-0362）
