基于ASTER数据的北山方山口地区蚀变矿物提取与找矿应用

针对北山方山口地区急需在老矿山深部及外围寻找新矿体的问题,以蚀变矿物为研究对象,通过ASTER遥感数据提取含Fe~(3+)、含Al-OH、含Mg-OH、含CO_3~(2-)和含石英的遥感蚀变异常,并结合野外验证和典型矿床的遥感剖析,总结遥感蚀变异常分布与区域成矿的关系,圈定遥感找矿预测区,为区域成矿规律研究提供依据。实验结果表明:研究区5种蚀变矿物提取结果正确率均超过80%,且遥感蚀变异常的分布与物化探异常具有较高的吻合度,已知金属矿(化)点也几乎都落在蚀变异常区内或边缘。遥感异常与成矿关系的分析表明以共生方式呈现的线性Fe~(3+)+(AlOH)+(Mg-OH)的蚀变矿物组合对研究区岩浆热液型矿化(特别是金矿化)有较好的指示意义。另外,基于相似类比法圈定的遥感找矿预测区也比较令人信服,在5处遥感找矿预测区内,野外查证已发现局部区域存在良好的矿化线索,这可为后续地质矿产调查提供有效指示信息。

Extraction and Application of Altered Mineral in Prospecting from ASTER Data in Fangshankou,Beishan

A very important and urgent problem for prospecting in Fangshankou of Beishan is to look for new ore body in an old mine.In this paper,the ASTER data were used to extract alteration mineral which containing Fe³⁺,Al-OH,Mg-OH,CO^3-2-or Quartz,and then the results is verified by field inspection.By analyzing the remote sensing anomaly characteristics of a typical mineral deposit,the relations between remote sensing anomaly and mineralization were analyzed,then the remote sensing prospecting prediction areas were delineate.The results indicate that the accuracy of five kinds of alteration minerals are more than 80%,and these remote sensing anomaly results are in good agreement with geophysical and geochemical anomalies.Moreover,through comprehensive analysis and verification,this study considers that there is no correlation between a single alteration mineral which was caused by regional metamorphism or by rock itself and mineralization,but the alteration mineral assemblage exists in a symbiotic mode is often related to mineralization,such as the alteration mineral assemblage(Fe³⁺⁺ Al-OH+ Mg-OH) in this paper has important instruction significance for magmatic hydrothermal mineralization (especially for gold mineralization).In addition,based on the similar analogy theory,we marked out five prospecting area of remote sensing,and some useful mineralization clues were found in those area by our field verification.So the study results will bring new inspiration for the geological prospecting work in research area.