Alteration Information Extracting Of Remote Sensing Image And Metallogenic Prognosis For The Xiongcun Cu-Au Distrcit,Xietongmen County,Tibet

The Xiongcun Cu-Au ore concentration area is located in Rongma township,Xietongmen county Rikaze city in Tibet,about 36km to the west of Xietongmen county,about 50km to the east of Rikaze city,and about 350km to Lhasa.The geotectonic position is located in the southern margin of the middle of the south lassa terrane,and the south side is adjacent to the Rikaze fore-arc basin.It is an important porphyry Cu-Au ore concentration area in the gangdes metallogenic belt,at present,No.1 and No.2 ore body research more deeply,No.1 ore body has entered the stage of mine construction,No.2 ore body has entered the stage of exploration.During the geological survey,there are several mineralization points on the periphery of the No.1and No.2 ore body,and The metallogenic geological conditions are superior,It shows the huge prospecting prospect in the Xiongcun ore concentration area.There are still a number of key scientific problems restricting the prospecting breakthrough.(1)For porphyry deposits,the surrounding rock alteration is of great significance to the location of the deposit,how to quickly to the Xiongcun ore concentration area surface alteration is to evaluate the current problem to be solved.(2)Previous studies have focused more on the genesis of ore body and on basic geological,the research on metallogenic prediction is weak and the comprehensive information integration also is weak,and there are difficult problems from metallogenic theory to prospecting practice.In this study,through the comprehensive arrangement and in-depth analysis of the previous data of the Xiongcun Cu-Au ore concentration area,fouce on the above two key scientific questions,we carried out the geological survey,analysis of typical ore deposits,remote sensing alteration information extraction and comprehensive research.For the purpose of metallogenic prediction,the alteration information is extracted from the Xiongcun ore concentration area,and the geological characteristics,geophysical characteristics,geochemical characteristics and remote sensing features of the Xiongcun ore concentration area are comprehensively analyzed,summed up the various elements related to mineralization,eight kinds of metallogenic prediction factors determined by comparative study.In the eight kinds of metallogenic prediction elements for prediction of geological variables,the metallogenic prediction is carried out by“R-D Metallogenic Blind Prediction Method”,and comprehensive evaluation prospecting potential of the Xiongcun ore concentration area,delineating the target area for prospecting and guiding the next step prospecting deployment.Through the above research,the paper has obtained the following main research results:(1)The geological conditions and geological characteristics of typical deposits are summarized.The main formation in the Xiongcun ore concentration area is the lower-middle Jurassic Xiongcun group(J_1-2x).The main bearing strata are Lower-middle Jurassic acid tuff,Anshan tuff,siltstone,Basic tuff in Xiongcun group.The ore body is controlled by NW and EW to fracture structure,and is distributed between1.5-2 km.The main ore bearing porphyry is early Jurassic quartz diorite porphyrite and middle Jurassic quartz diorite porphyrite with big quartz eyes.Porphyry and the near of tuff develop fine vein and disseminated copper gold mineralization,vein bearing body are quartz-sulfide vein,biotite-sulfide vein and chlorite-sulfide vein,and there are surrounding rock alteration of a typical porphyry deposit.(2)The high precision magnetic survey anomalies with known No.1 and No.2ore body location has good coupling relationship.Near the No.1 ore body exists low magnetic anomaly,the anomaly range between 49000-49100n T,Near the No.1 ore body exists high magnetic anomaly,the anomaly range between 49100-50000n T,high magnetic anomaly is caused by No.2 ore body contains more magnetite.Geomagnetic anomaly is an important geophysical prospecting indicator(3)The rock geochemical survey and soil geochemical survey results are similar.The element of Cu,Au and Ag is the main indicator element of near ore halo,and Pb,Zn and As elements are the main leading edge halo indicator elements.Elements of Cu,Au anomaly range and No.1 and No.2 ore body location has good coupling relationship.Geochemical anomalies of rocks and soils are important geochemical prospecting indicators.(4)The remote sensing alteration information extraction uses ASTER data,the extraction of alteration information uses the method of principal component analysis(PCA).Six kinds of remote sensing alteration information were extracted,potassic alteration,sericitization,beresitization,argillization,propylitization and iron-stained,density segmentation to alteration information,and determine the anomaly classification of different alteration information.Based on comprehensive evaluation,two main ore alteration are selected(potassic alteration and beresitization)as the geological variables for the study of metallogenic prognosis.(5)The"R-D Metallogenic Blind Prediction Method"is applied to predict the metallogenic prognosis of Xiongcun ore concentrated area.The delineation of the 4prospecting target area are ZKBQ-1,ZKBQ-2,ZKBQ-3 and ZKBQ-4.According to the geological survey,the ore-forming area is evaluated,the prospecting direction of the Xiongcun ore concentration area is determined,and some suggestions for the prospecting of the Xiongcun ore concentration area are put forward.