GeoAHSI新工具精确刻画新疆哈密赤湖铜钼矿床蚀变分带特征

Accurate characterization of the alteration zoning in Chihu copper-molybdenum deposit by a new tool GeoAHSI in Hami area of Xinjiang

蚀变分带特征能够指示与斑岩型矿床相关的热液蚀变活动,是斑岩型矿床的重要找矿标志之一。高光谱遥感数据凭借精细的光谱信息,能够准确刻画各类热液蚀变矿物的空间分布,从而为斑岩型矿床的识别和定位提供可靠依据。以Teracorder算法框架为基础,开发并开源了适用于国产高光谱数据矿物识别工具GeoAHSI,实现了便捷、高效的国产高光谱遥感数据批量处理和矿物填图工程化应用。在此基础上,使用GF-5高光谱成像仪(Advanced Hyperspectral Imager,AHSI)影像作为遥感数据源,结合野外采样分析,对赤湖铜钼矿床进行了地表矿物填图及验证工作。结果表明,AHSI高光谱矿物填图结果精细地刻画出了以叶腊石+明矾石为核心,向外逐渐过渡高岭石+叶腊石和高岭石+白云母蚀变矿物组合的典型斑岩型矿床热液蚀变分带特征,并与传统地质填图单元和构造具备较好的空间分布一致性。此外,GeoAHSI工具还提取了该地区白云母吸收特征波长分布,揭示了赤湖铜钼矿床富铝白云母与斑岩型矿化之间的关系。研究为斑岩型矿床蚀变矿物及蚀变分带识别提供了成熟、有效的工具及方法,对推动国产高光谱遥感卫星支撑新一轮找矿突破战略行动具有一定指导意义。

The characteristics of alteration zoning can indicate the hydrothermal alteration activities associated with porphyry deposits,making it the important prospecting indicators for porphyry deposits.Based on fine spectral resolution,the hyperspectral remote sensing data can accurately delineate the spatial distribution of various hydrothermally altered minerals,providing reliable basis for the identification and localization of porphyry deposits.Based on the Teracorder algorithm framework,the authors developed and made open-source of GeoAHSI,a mineral identification tool for domestic hyperspectral remote sensing satellite imagery,to achieve convenient and efficient batch processing and mineral mapping engineering applications of domestic hyperspectral remote sensing satellite imagery.Based on the research basis and field sampling analysis,the GF-5 AHSI(Advanced Hyperspectral Imager)imagery was used as remote sensing data source to carry out surface mineral mapping and verification work in Chihu copper-molybdenum mining area.The results show that AHSI hyperspectral mineral mapping accurately characterized the typical hydrothermal alteration zoning characteristics of porphyry deposits with pyrophyllite+alunite as the advanced argillic alteration core and gradually transitioning outward to kaolinite,pyrophyllite,muscovite and other altered mineral assemblages.Moreover,the mineral map had good spatial distribution consistency with traditional geological mapping units and structures.In addition,the GeoAHSI tool also extracted absorption characterization and wavelength distribution of muscovite in this area,and revealed the relationship between aluminum rich muscovite and porphyry mineralization in Chihu copper molybdenum deposit.The study provides a mature and effective tool and corresponding methods for the identification of alteration zoning for porphyry deposits,which could help promote the domestic hyperspectral remote sensing satellites utilities in the new round of mineral exploration breakthroughs.