基于哨兵-2数据的白岗岩型铀矿构造蚀变特征研究——以纳米比亚罗辛矿区为例

Structural and Alteration Characteristics of Alaskite Type Uranium Deposit Based on Sentinel-2 Data:An Example From the Rossing Mine,Namibia

白岗岩型铀矿是重要的铀矿资源,但针对该类铀矿典型矿床遥感特征的研究还十分薄弱。文章以纳米比亚罗辛铀矿区为研究对象,获取了该矿区哨兵-2遥感影像,总结了矿区典型蚀变矿物的光谱吸收特征,建立了针对矿区地质体的增强与构造解译方法。在此基础上,对获取的遥感影像进行了大气校正与几何校正,并应用主成分分析、波段比值等方法,提取了铁染、羟基和碳酸盐化蚀变信息。结果表明,罗辛铀矿中碳酸盐化蚀变在空间上与卡里毕比组的分布较为一致。通过选取合理的阈值,识别出与铀成矿相关的含大理岩地层。同时,对图像进行增强,并利用建立的构造解译方法,对罗辛铀矿的构造进行了识别。经野外查证,发现遥感识别构造、蚀变与野外查证结果一致,说明利用哨兵-2数据可以对白岗岩型铀矿的成矿条件与控矿要素进行识别,进而为铀矿勘查提供参考。

Alaskite uranium deposit is an important beneficial type in the worldwide.However,research on the remote sensing characteristics of this type is seldom reported.In this paper,Sentinel-2 remote sensing imagery was used to study the the spectral absorption characteristics of typical alteration minerals and structural feature in Rossing uranium mine.Sentine l-2 imagery of the mining area was collected and subjected to atmospheric and geometric correction.Principal component analysis and band ratio methods were applied to extract information related to ferric,hydroxyl and carbonate alteration.The extraction results indicated that carbonate alteration in Rossing uranium mine spatially correlated well with the distribution of the Karibib Formation.By selecting reasonable threshold values,the uranium-related host rocks,such as dolomitic units was extracted.Image enhancement techniques were studied to help the structural interpretation in the Rossing uranium deposit.Field verification confirmed the consistency between the remote sensing identified structures and alteration with the outcrops.This study demonstrated that the Sentinel-2 data are capable in the identification of mineralization controlling factors in white Alaskite uranium deposits and can provide valuable references for uranium exploration.