中等程度植被覆盖区岩石蚀变信息提取技术及其应用

各种类型的热液型矿产经常与围岩蚀变相伴生,蚀变岩类是找矿标志之一。陆地卫星TM数据在短波近红外范围内有二个波段,这两个波段的信息可用来进行蚀变岩的制图。可是在有部分或中等密度的植被复盖区,由于植被和蚀变岩类的反射光谱特性比较相似,影响了TM数据的制图能力。笔者开发了三种用来在中等程度植被复盖区进行蚀变岩类信息提取方法。这三种方法是:直接主成分分析法、最小平方拟合法和混合单元分解法。在滇黔桂微细浸染型金矿勘查中,这三种方法被成功地用来提取与金矿化有关的粘土蚀变岩类信息和制图。

THE TECHNIQUE DEVELOPMENT AND APPLICATION OF LANDSAT TM DATA FOR ALTERATION INFORMATION OF ROCKS MAPPING IN MIDDLE DENSITY VEGETATION AREA

Mineralization often is related to altered rocks. Landsat TMwith two bands within the short infrared wavelength (1. 1-2.5 μm) supples the ability for altered rocks mapping. But the vegetation covery masks the altered rocks information and confuses the reflectance spectrum. Three methods were developed for altered rock mapping in middle density vegetation area. They are principal component analysis, least square fit and unmixing. These methods are successfully applied in DianQingGui area for disseminated gold exploration. The clay minerals distribution information which is related to disseminated gold deposits were extracted and mapped,