Remote Sensing Anomaly Information Extraction And Prospecting Prediction Of Porphyry Copper Deposits In Songnuo-Dadisuyu Area, Northwestern Yunnan

It's difficult to promote geological ore-prospecting work in Songnuo-disuga mining area,which is located in the plateau region in northwest of Yunnan,because of its high plant cover degree.In this thesis,taking Songnuo-disuga mining area as the research area,geological,geophysical,and geochemical data are collected and analyzed based on remote sensing technology.On the basis of geological interpretation of remote sensing images,the character of remote sensing anomalies related with mineralization in mining area is analyzed and summarized meanwhile ore-prospecting model of regional remote sensing is built.Metallogenic prognosis is conducted by using weights of evidence method in MRAS(Mineral Resource Assessment System)software platform.Sectors with ore-prospecting potential are identified in Songnuo-disuga mining area.By field investigation,the main research results are as follows:1.Interpretation symbol for linear-ring structure in remote sensing images is established which is used for information extraction of remote sensing alteration anomalies related with mineralization.The relationships between and among linear-ring structure,alteration zoning,and mineralization are fully discussed to identify the character of remote sensing anomalies related with regional mineralization.2.A typical porphyry Cu deposit in Songnuo-disuga mining area is chosen as research object to analyze geological metallogenetic and ore-controlling conditions.An ore-prospecting model of regional remote sensing with weights of evidence method basing on MRAS software is built.In this method,weight factors are as follows:information of remote sensing anomalies related with mineralization,remote sensing interpretation of linear structure,remote sensing interpretation of ring structure,hidden fault and rock body,and favorable ore-forming strata.3.According to analysis information of remote sensing anomalies related with mineralization,geological metallogenic theory and remote sensing geology theory,this thesis establishes 10 thematic map layers:linear structure buffer zone layer,favorable ore-forming zone of line structure layer,linear-ring structure combination buffer zone layer,geochemical anomaly information layer,potassium feldspar alteration anomalies information layer,quartz alteration anomalies information layer,sericitization alteration anomalies information layer,chlorite alteration anomalies information layer,epidote alteration anomalies information layer,favorable ore-forming strata layer.This thesis also represents quantitative research on remote sensing alteration anomalies related with metallogenic prognosis,which is based on MRAS with weights of evidence method to find favorable ore-prospecting area by hierarchical extraction.That is to say,three levels of favorable ore-prospecting areas,Class 1,Class 2 and Class 3,are provided according to relative values of posterior probability in weights of evidence method.After field investigation and result summary,this research can provide theoretical basis and method guidance to further ore-prospecting work in research area or other similar areas.