航空红外扫描成像识别碳酸盐岩石的方法研究

Study on the Discrimination of Carbonatites Using Airborne Infrared Scanning Imaging Techniques

本文主要叙述了用DS-1260多光谱扫描仪夜间获取的热图数据(8～14μm),经计算机图像增强处理,区分出未蚀变的白云岩、硅化白云岩以及灰岩。并对这几种岩石的热惯量的几个参数进行了测定,计算出它们的热惯量值,用热惯量这一物理性质和岩石辐射温度测量的结果,结合化学分析,来解释这几种碳酸盐岩石的成像机理。结果表明,白云岩比灰岩的热惯量高,在夜间辐射温度也比较高,所以在热图像上白云岩呈现暖色调(亮色调),灰岩呈稍冷色调(暗色调)。几种碳酸盐岩石中,二氧化硅含量高者,其热惯量值偏低,这是二氧化硅吸收红外的缘故。这对用红外遥感识别有关蚀变带,圈定成矿远景区的应用,是很有意义的。

The paper presents some results of rock type discrimination using digitally enhanced thermal (8～14μm) image acquired by a DS-1260 multispectral scanner at night. The unaltered dolomite, the silicified dolomite and the limestone are well discriminated and several thermal inertia parameters of these rocks are measured. Combined with the results of rock radiant temperatur measurement and chemical analysis, the imaging mechanisms of these carbonatites are explained. The results show that the thermal inertia of dolomite is higher than that of limestone, and the former has a relatively higher radiant temperature at night, which accounts for the bright tone of dolomite and the dark tone of limestone on the thermal image. The silicified dolomites have higher contents of silicon dioxide than the unaltered and their lower inertia values can be attributed to the absorption characteristics of silicon dioxide. The results presented in this paper can be utilized for discriminating alteration zones and mapping prospective areas of mineralization.