遥感矿化蚀变分带弱信息增强提取方法研究——以普朗斑岩型铜矿区为例

Research on enhanced extraction method for weak information of remote sensing mineralization alteration zoning: A case study of the Pulang porphyry copper deposit

为弥补以往研究中遥感矿化蚀变信息提取精细化程度不高、对西南三江斑岩型铜矿深部找矿勘查推进支撑作用有限的不足,针对西南三江成矿带中南段滇西北普朗斑岩型铜矿区矿化蚀变分带从外至内呈青磐岩化—硅化绢云母化—钾化硅化分布的特点,分析斑岩型铜矿矿化蚀变分带的特征矿物组成、诊断性波谱及其ASTER遥感波谱响应;采用多重分形"广义自相似性"和"局部奇异性"理论与能谱面积法(S-A法),探索复杂地质背景条件下斑岩型铜矿蚀变分带特征矿物,即青磐岩化(绿泥石、绿帘石)、硅化绢云母化(石英、绢云母)和钾化(钾长石)硅化(石英)等弱信息增强与提取方法;通过对遥感蚀变分带结果进行实地查证及岩矿鉴定,印证了本文构建的斑岩型铜矿蚀变分带遥感异常增强和提取方法的可靠性。

To compensate the insufficiency of previous studies shown by the low degree of refined extraction of remote sensing mineralization alteration and the limitation of the supporting role for advancing prospecting and exploration of Southwest Sanjiang deep porphyry copper deposits, the authors took into account the zoning characteristics of the mineralization alteration of the Pulang porphyry copper ore district in the central south segment of the southwest Sanjiang metallogenic belt, i. e. , propylitization - sericitization - silicification and potassic alteration from outside to inside of the alteration zone and, on such a basis, analyzed the features of the characteristic minerals,the diagnostic spectra and ASTER remote sensing spectral response of the porphyry copper mineralization and alteration zonation. With the multifractal theory of“generalized self similarity” and“singularity”and the method of energy spectrum area （ S-A） ,the authors probed into the enhancement and extraction methods for the weak information of the characteristic minerals in the porphyry copper alteration mineral zone under the condition of complex geological background, including the propylitization （ chlorite and epidote ） , lithification （ quartz and sericite ） , potassium （ potassium feldspar ） and silica （ quartz ） . Through the field test of the remote sensing alteration zoning results and mineral identification, the reliability of the methods of enhancement and extraction of the remote sensing abnormal information for the porphyry copper ore alteration zoning was confirmed.