世界核地质科学

蚀变是热液活动与成矿过程的重要指示标志之一。基于GF-5高光谱数据，利用光谱角填图（SAM）、光谱特征拟合（SFF）、混合像元调谐匹配滤波（MTMF）等手段，在新疆雪米斯坦东段火山岩区开展热液蚀变提取与蚀变矿物组合分析，在此基础上进行铀成矿远景区预测。研究发现，雪米斯坦东段热液蚀变以绢云母化为主（含高、中和低铝绢云母），次为绿泥石化和铁氧化物/氢氧化物等；蚀变主要沿近北西、近东西及北东向构造带分布，呈条带状、斑块状和局部叠加状；高铝绢云母-铁氧化物组合主要发育于断裂交汇部位、火山岩破碎带内及部分侵入岩接触带附近，反映相对高温、酸性的热液交代和后期氧化作用；绢云母-绿泥石组合则多见于中、基性火山围岩中，指示中、低温热液交代。结合雪米斯坦成矿带内已知铀矿的成矿模式、控矿要素和蚀变特征，本文认为该区东段高、中、低铝绢云母+绿泥石+铁氧化/氢氧化物+断裂交汇节点/火山-侵入岩接触带为有利成矿地段，由此预测重点区1片，次重点区2片，一般远景区1片。研究表明GF-5 高光谱数据能为雪米斯坦东段热液蚀变提取和铀成矿远景预测提供有效依据。

Hydrothermal alteration serves as one of the crucial indicators of hydrothermal activity and metallogenic processes. Based on GF-5 hyperspectral data，this study employs techniques such as Spectral Angle Mapper （SAM），Spectral Feature Fitting （SFF），and Mixture Tuned Matched Filtering （MTMF）to extract hydrothermal alteration and analyze alteration mineral assemblages in the volcanic rock area of the eastern Xuemisitan region，Xinjiang. On this basis，uranium prospecting target areas are predicted. The results indicate that the hydrothermal alteration in the eastern Xuemisitan region is predominantly sericitization （including high-，medium-，and low-aluminum sericite），followed by chloritization and the presence of iron oxides/hydroxides. Spatially，these alterations are mainly distributed along near-NW，near-EW，and NE trending structural belts，exhibiting banded，patchy，and locally superimposed patterns. The assemblage of high-aluminum sericite and iron oxides is primarily developed at fault intersections，volcanic rock fracture zones，and near the contact zones of certain intrusive rocks，reflecting relatively high-temperature and acidic hydrothermal metasomatism coupled with subsequent oxidation. Conversely，the sericite-chlorite assemblage is commonly found in intermediate to mafic volcanic host rocks，indicating medium- to low-temperature hydrothermal metasomatism. Integrating the metallogenic model，ore-controlling factors，and alteration characteristics of known uranium deposits within the Xuemisitan metallogenic belt，this study suggests that the eastern segment with the combination of high-，medium-，and low-aluminum sericite，chlorite，iron oxides/hydroxides，and structural intersections/volcanic-intrusive rock contact zones represents favorable metallogenic domains. Consequently，one key prospect area，two secondary prospect areas，and one general prospect area have been delineated. This research demonstrates that GF-5 hyperspectral data can provide an effective basis for hydrothermal alteration extraction and uranium prospecting prediction in the eastern Xuemisitan region.