湖南界牌岭大型锡-萤石矿床勘查模型与深部找矿预测

湖南界牌岭锡多金属矿床位于南岭成矿带中段，是近年来新发现的以锡和萤石为主，伴生锂、铍、铌、钽、锌等重要资源的大型矿床。该矿床矿化元素多且规模大、矿化分带性强、成矿时代也较新（~90 Ma），使其在湘南钨多金属矿集区内独具特色。文章在详细的矿床地质工作基础上，对界牌岭不同矿化段的萤石和锡石进行了矿物学研究和微区原位微量元素对比分析。研究结果显示，萤石由深到浅表现为明显的正Ce异常向负Ce异常、负Eu异常向正Eu异常转变，指示成矿流体向上运移过程中氧逸度逐渐升高。浅部矿体与深部花岗斑岩中萤石的稀土元素配分特征一致，指示两者均为深部富F花岗质岩浆的产物。相较于南岭地区云英岩型和石英脉型锡矿，界牌岭锡石中Nb-Ta含量偏低，但高于矽卡岩型锡矿，具有富Fe、贫W的特征，较低的Zr/Hf值（平均为2.76）。对比研究认为，界牌岭锡矿体仍处于该岩浆热液系统中-远端，推测其深部至隐伏岩体仍具较大找矿空间。结合前人研究，文章综合构建了界牌岭锡萤石矿床成矿模式，并提出了相应的勘查标识，圈定了界牌岭深部近花岗岩体矽卡岩型-云英岩型-石英细脉型锡（钨）铌钽矿、北北东向主断裂北段深部锡多金属矿、斑岩体内及深部接触带锡锂铌钽矿3个方向的找矿预测靶区。

Exploration model and deep prospecting prediction of Jiepailing tin-fluorite deposit in Hunan Province, China

Located in the heart of the Nanling metallogenic belt, the Jiepailing Sn-polymetallic deposit is a newly discovered large-scale deposit in recent years, primarily comprising tin and fluorite, and associated with important resources such as Li, Be, Nb, Ta and Zn. The deposit has an array of mineralized elements and large scale, strong mineralization zonation, and a relatively recent metallogenic era, estimated at around 90 million years ago, which makes it unique in the W-polymetallic ore concentration area in southern Hunan. Through meticulous geological investigations of the deposit, a thorough mineralogical study ensued, accompanied by a comparative analysis of in-situ trace elements found in fluorite and cassiterite across various mineralized sections of Jiepaling deposit. The findings elucidate a discernible shift in fluorite characteristics from a positive Ce anomaly to a negative Ce anomaly, and from a negative Eu anomaly to a positive Eu anomaly as depth decreases. This delineates a gradual escalation in the oxygen fugacity during the ascension of the ore-forming fluid. The REE partitioning features observed in fluorite from both the shallow ore body and the deep granite porphyry maintain a congruence, suggesting their shared genesis from profound, F-rich granitic magma. In contrast to the greisen type and quartz vein type tin deposit in Nanling range, the Nb-Ta content in the Jiepailing cassiterite is relatively low, but higher than that of skarn-type tin deposit, which rich in Fe and poor in W, and has a lower Zr/Hf value, averaging at 2.76. The comparative analysis suggests that the Jiepaling tin orebody still resides within the intermediate and distant reaches of the magmatic-hydrothermal system. This suggests a significant prospecting potential extending from the depths down to concealed rock formations. Leveraging prior studies and the mineralogical study in this paper, a comprehensive metallogenic model for the Jiepaling tin-fluorite deposit has been meticulously crafted, accompanied by the proposal of corresponding exploration indicators. The delineation encompasses prospective prediction targets in three directions:the skarn-greisen-quartz vein-type tin(tungsten)niobium-tantalum ore in the deep near-granite of the Jiepailing deposit, deep tin polymetallic ore in the northern section of the NNE-trending main fault, tin-lithium-niobium-tantalum ore in porphyry body and deep contact zone.