西藏冈底斯地区斑岩铜矿识别的最佳多光谱遥感异常判据研究

Study of optimum discriminator of multi-channel remote sensing anomaly for recognition of porphyry Cu deposits in Gangdese belt

文章应用多光谱遥感技术,对冈底斯斑岩铜矿带的实例(驱龙、甲玛、朱诺、冲江、夏玛日等矿床)进行了研究和总结,包括ASTER和ETM+数据技术特征、蚀变异常找矿的地质依据、蚀变异常提取的波谱前提、多光谱矿致遥感异常提取的常见技术方法、去干扰异常主分量门限化技术流程、冈底斯斑岩铜矿带找矿模型最佳遥感异常判据研究等。确定了ASTER主分量分析提取的羟基异常OHA6、OHA5同心套合异常可做为斑岩铜矿的最佳多光谱遥感异常判据,在从夏玛日至朱诺的13景共4.6万平方公里的ASTER提取异常中,依此判据圈定了冈底斯20处有潜能的斑岩铜矿异常。此外,还对夏玛日景遥感异常进行了解译,并提出了3处钻孔孔位建议。

Exemplified by Qulong,Jiama,Zhunuo,Chongjiang and Xiamari deposits,the authors summarized the techniques for the porphyry Cu deposits of Gangdise belt in Tibet and studied the optimum discriminator of multi-channel remote sensing anomaly for recognition of porphyry Cu deposits in Gangdese belt.The problems studied included the technical characteristics of the ASTER and ETM data,the geological basis and the spectral precondition for extraction of alteration anomaly,the common methods for the extraction of the remote sensing anomaly related to mineralization,and the technical flow chart of de-interfered principle component thresholding.the concentric anomaly of OHA6 and OHA5 by PCA was defined as the optimum discriminator of multi-channel remote sensing anomaly for recognition of porphyry Cu deposits in Gangdise belt.With this discriminator,20 anomalies were delineated as the potential targets in an area of 46 000 km2 from Xiamari to Zhunuo within Gangdese belt.Geological interpretation was made for Xiamari ASTER data and 3 drilling spots were suggested.