基于红外光谱技术的锡多金属矿床蚀变分带特征及找矿预测研究——以武夷山成矿带南段枫树卜区域为例

Alteration zonation characteristics and mineral prospectivity prediction of tin-polymetallic deposits based on infrared spectroscopy: A case study of Fengshubu area, southern Wuyishan metallogenic belt

中文关键词:红外光谱  蚀变矿物  指针矿物  枫树卜

keywords:infrared spectroscopy  alteration minerals  indicator mineral  Fengshubu

中文摘要:枫树卜位于江西省会昌县，地处武夷山成矿带南段锡坑迳矿田。矿田内已探明岩背锡矿体10.24万吨，但深边部区域找矿潜力不详。作者采用短波红外+热红外光谱技术对枫树卜(岩背外围)开展了基于地表岩石和钻孔岩芯的测量，共获得3800条红外光谱数据，发现：(1)钻孔中蚀变矿物主要有绢(白)云母、绿泥石、蒙脱石、高岭石、黑云母、黄玉、萤石、石英、钾长石和钠长石等，其中黄玉、萤石、绿泥石矿物与锡矿体的空间关系密切；(2)黄玉在2086 nm处存在稳定的吸收峰，其光谱吸收深度与Sn品位呈正相关关系，可作为指针矿物指示流体运移的轨迹与成矿环境的变化；(3)经空间插值分析与三维建模验证后发现研究区中部与北东部仍具有Sn找矿潜力。其中中部潜力区目前已通过钻孔验证，获得Sn潜在资源量超5000 t，下一步工作将针对北东部潜力区继续开展工作。

Abstract:Fengshubu, located in Huichang County, Jiangxi Province, lies within the Xikengjing ore field in the southern segment of the Wuyishan metallogenic belt. A total of 102.4 kt of tin resources have been identified in the Yanbei tin orebody within the ore field; however, the prospecting potential in its deeper and peripheral areas remains unclear. In this study, shortwave infrared(SWIR) and thermal infrared(TIR) spectroscopy were applied to Fengshubu(the peripheral area of Yanbei) based on measurements of surface rock samples and drill-core specimens, yielding 3800 infrared spectra. The results show that:① the main alteration minerals in the drill cores include sericite(muscovite), chlorite, montmorillonite, kaolinite, biotite, topaz, fluorite, quartz, K-feldspar, and albite, among which topaz, fluorite, and chlorite are spatially closely associated with tin orebodies;② topaz exhibits a stable absorption feature at 2086 nm, and its spectral absorption depth is positively correlated with Sn grade,indicating that topaz can serve as an indicator mineral for tracing fluid migration pathways and changes in the oreforming environment; and ③ spatial interpolation analysis and three-dimensional modeling reveal that the central and northeastern parts of the study area still have considerable tin prospecting potential. The central target area has already been verified by drilling, resulting in an inferred potential Sn resource of more than 5000 t, and future work will continue to focus on the northeastern target area..