西藏马攸木地区多源遥感蚀变信息提取研究及找矿预测

    The Study on Multi-Source Remote Sensing Alteration Information Extraction and Mineral Exploration Prediction in the Mayum Area, Tibet

    • 摘要: 近年来,随着国内外地球观测技术的不断进步,遥感技术已逐渐成为地质调查和矿产资源勘查等领域的重要手段。西藏作为国家新一轮找矿突破战略行动的关键靶区,因其地表植被覆盖度低等独特地貌特征,为遥感识别与提取蚀变异常信息提供了得天独厚的条件。本文以西藏马攸木地区为研究对象,综合运用多源遥感技术开展矿化蚀变信息提取,并结合1: 20万化探数据分析圈定有利找矿区域,辅以野外路线调查,以加深对遥感矿化蚀变信息的理解与研究。在数据选择方面,本文选取了Landsat-8与Sentinel-2多光谱数据,结合主成分分析法和波段比值法,提取了研究区内的铁染和羟基类蚀变异常信息,并采用门限法对异常强度进行了分级。同时,利用高分五号(GF-5)高光谱数据,应用混合调制匹配滤波(MTMF)技术,提取出褐铁矿化、磁铁矿化、白云母化及方铅矿化等多种蚀变异常类型。将多源遥感蚀变信息提取结果叠加,与利用对数比变换(ILR)变换与稳健主成分分析(RPCA)方法结合的方法所获取的1: 20万化探有利成矿区域及已知矿(化)点进行对比分析,从而在研究区内圈定了多处具有成矿潜力的找矿远景区,野外实地验证结果进一步证实了本文遥感提取方法的准确性,也为研究区下一步的矿产勘查工作提供了理论依据和勘查方向。

       

      Abstract: In recent years, with the continuous advancement of Earth observation technologies both domestically and internationally, remote sensing has gradually become a crucial tool in geological surveys and mineral resource exploration. As a key target area in China's new round of strategic mineral exploration breakthrough initiatives, Tibet—with its sparse vegetation coverage and other unique geomorphological characteristics—offers favorable conditions for the remote sensing identification and extraction of alteration anomalies. This study focuses on the Mayum area in Tibet, employing a comprehensive approach that integrates multi-source remote sensing technologies to extract mineralization-related alteration information. By combining these data with 1: 200, 000 geochemical survey results, the study delineates favorable mineralization zones, further validated through field investigations to enhance understanding and interpretation of remotely sensed alteration signals. For data selection, this research utilizes multispectral data from Landsat-8 and Sentinel-2 satellites. Techniques such as Principal Component Analysis (PCA) and band ratio methods are applied to extract iron staining and hydroxyl alteration anomalies within the study area, and the threshold method is used to classify the intensity levels of these anomalies. Additionally, hyperspectral data from Gaofen-5 (GF-5) are processed using the Mixture Tuned Matched Filtering (MTMF) technique to identify various types of alteration anomalies, including limonitization, magnetitization, sericitization, and galenitization. The results from the multi-source remote sensing extraction are overlaid and compared with favorable metallogenic zones derived from the combination of isometric log-ratio (ILR) transformation and Robust Principal Component Analysis (RPCA) on the 1: 200, 000 geochemical data, as well as known mineral (mineralized) occurrences. As a result, several prospective exploration targets with significant mineralization potential are identified within the study area. Field validation further confirms the reliability of the remote sensing extraction methods employed in this research, providing both theoretical support and directional guidance for subsequent mineral exploration efforts in the region.

       

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