ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    赣东上水桥萤石矿床萤石微量元素地球化学特征及其对矿床成因的指示

    Trace Element Geochemical Characteristics of the Shangshuiqiao Fluorite Deposit in Eastern Jiangxi with Implications for the Genesis of the Deposit

    • 摘要: 赣东黎川上水桥萤石矿床位于华南褶皱系武夷成矿带北端,产于燕山期黑云母花岗岩的断裂破碎带内。笔者对该矿床的地质特征、不同颜色萤石及围岩黑云母花岗岩的微量元素地球化学特征进行了研究。结果表明,萤石整体上呈现Eu正异常和Ce负异常,但不同颜色的萤石REE配分模式特征有差异,浅绿色、深绿色和紫色萤石为轻稀土富集型,白色萤石为重稀土富集型。围岩的REE配分模式为轻稀土富集型,整体呈现Eu负异常。Y/Ho-La/Ho关系图和REE配分模式图显示,萤石成矿过程中Y-REE发生了分馏,白色萤石成矿时期最晚。Tb/Ca-Tb/La关系图显示,研究区萤石矿床为热液成因。围岩黑云母花岗岩的微量元素配分曲线变化趋势与萤石基本一致,且围岩和萤石的Sm/Nd值十分接近。越靠近矿体的围岩F含量越高,且近矿围岩发生硅化、绢云母化等蚀变,推测萤石矿中的Ca和F主要来自围岩。矿区内萤石形成于中低温氧化环境,矿床成因类型为多期次的中低温热液充填型萤石矿床。

       

      Abstract: The Shangshuiqiao fluorite deposit in Lichuan, eastern Jiangxi, is located at the northern end of the Wuyi metallogenic belt in the South China fold system and is produced in the fractured fracture zone of Yanshanian biotite granite. This paper investigates the geological characteristics of the deposit, as well as the trace element geochemical features of different-colored fluorites and the surrounding biotite granite. The results show that fluorite shows positive Eu anomalies and negative Ce anomalies as a whole, but the REE distribution pattern characteristics of different colors of fluorite are different. Light green, dark green and purple fluorite are light rare earth enriched types, and white fluorite is heavy rare earth enriched type. Enriched type. The REE distribution pattern of the surrounding rock is light rare earth enriched type, and the overall negative Eu anomaly is present. The Y/Ho-La/Ho relationship diagram and REE partitioning model diagram show that Y-REE fractionation occurred during the fluorite mineralization process, and the white fluorite mineralization period was the latest. The Tb/Ca-Tb/La relationship diagram shows that the fluorite deposits in the study area are of hydrothermal origin. The change trend of the trace element distribution curve of the surrounding rock biotite granite is basically the same as that of fluorite, and the Sm/Nd values of the surrounding rock and fluorite are very close. At the same time, the F content in the surrounding rocks closer to the ore body is higher, and the surrounding rocks near the ore undergo alterations such as silicification and sericitization. It is inferred that Ca and F in the fluorite ore mainly come from the surrounding rocks. The fluorite in the mining area was formed in a medium-low temperature oxidation environment, and the deposit formation type is a multi-stage medium-low temperature hydrothermal filling type fluorite deposit.

       

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