敦煌地块南缘多坝沟地区遥感解译与找矿预测

REMOTE SENSING INTERPRETATION TO ORE-PROSPECTING PROGNOSIS OF DUOBAGOU IN SOUTHERN DUNHUANG BLOCK

为了研究敦煌地块南缘多坝沟地区铁、金、稀有金属等多金属成矿区的找矿远景,在对Landsat7 ETM^+数据进行几何纠正、大气校正和去干扰等预处理的基础上,对多波段假彩色合成图像做滤波处理以增强区域构造信息、进行线性构造解译;运用分形几何学原理和计盒维数法求取线性构造分维值,得到线性构造的统计自相似性和分形特征;采用主成分分析和阈值分割法对图像进行铁染、羟基蚀变信息提取;最后根据区内线性构造、遥感蚀变信息、岩体分布特征、区域地球化学异常和已知矿化(点)分布资料综合分析,圈定出3个级别的6个找矿预测区。

Using ETM+remote sensing data as the basic information sources,the authors carried out remotesensing geological prospecting in Fe、Au、Rare metals and polymetallic ore zones of Duobagou in southern Dunhuang block,Remotesensing image was processed by geometric correction,atmospheric correction and the noise removal technology.Image filtering was conducted so as to enhance tectonic information and explain linear structure;The fractal dimension values were calculated by the method of fractal geometry and the box-counting dimension.As a result,the linear structures showed excellent statistical self-similarity and fractal characteristics in the study area.Principal component analysis and threshold segmentation were used to enhance the spectrum and space information and extract the iron-stained and hydroxy alteration information.Through comprehensively analyzing the linear structure,remote sensing alteration information,rock mass distribution characteristics,regional geochemical information and known deposits,six metallogenic prospective areas at three levels were delineated.