福建邵武地区萤石矿微量、稀土元素特征及对成矿物质指示

Characteristics of trace and rare earth elements of fluorite ore in Shaowu area,Fujian Province and its indication to ore-forming materials

【研究目的】福建邵武地区是中国重要的萤石矿成矿远景区,该区氟化工企业众多,近年来萤石后续资源储备不足的问题愈发明显,开展区内萤石矿床地质、地球化学特征研究,探讨萤石矿床成因和成矿物质来源,指导区内萤石矿找矿工作,对保障该区萤石矿资源供应具有重要意义。【研究方法】通过典型萤石矿床萤石和围岩的稀土、微量元素地球化学研究,系统总结了研究区萤石矿床地质特征及分布规律。【研究结果】萤石和围岩的稀土元素特征均为轻稀土相对富集,重稀土相对亏损,萤石和围岩稀土配分曲线具有相似同步性。【结论】(1)综合研究区萤石矿地质、微量、稀土元素特征和La/Ho-Y/Ho、Tb/Ca-Tb/La关系图,结合前人在华南地区萤石气液包裹体氢氧同位素特征研究结果,认为福建省邵武地区萤石矿为沿断裂构造充填的中低温热液充填型萤石矿床;(2)成矿物质F和Ca元素来源于大气降水对围岩燕山早期黑云母正长花岗岩的淋滤和萃取。

[Objective]Shaowu area in Fujian Province is an important fluorite mineralization prospect area in China.There are many fluorite chemical enterprises in this area.In recent years,the problem of insufficient reserves of fluorite follow-up resources has become increasingly obvious.We carry out research on the geological and geochemical characteristics of fluorite deposit,study the genesis of fluorite and the source of ore-forming materials to guide the prospecting of fluorite ore in this area,and ensure the supply of fluorite resources in this area.[Methods]This paper summarizes the geological characteristics and distribution of fluorite deposit in the study area systematically based on rare earth and trace elements of fluorite and surrounding rocks of typical fluorite deposits.[Results]The fluorite and surrounding rock are relatively enriched in LREE and relatively depleted in HREE with similar rare earth partition curve.[Conclusions]Based on the geology,trace and rare earth elements characteristics of fluorite ore and La/HO-Y/Ho and Tb/Ca-Tb/La relationship diagram,and combined with previous studies on hydrogen and oxygen isotope characteristics of fluorite gas-liquid inclusions in South China,it is concluded that the fluorite deposit in the Shaowu area of Fujian Province is a medium-low temperature hydrothermal filled fluorite deposit along fault structure;(2)The ore-forming materials(F and Ca elements)are derived from the leaching and extraction of early Yanshanian biotite syenite granite by fresh water.