Extraction And Analysis Of Mineralized Alteration Anomaly Information Based On Sentinel-2A

Remote sensing ore prospecting technology has been widely used as an efficient and accurate mineral resource exploration method.The Ganzi Tibetan Autonomous Prefecture of Sichuan Province is located at the southeastern edge of the Songpan geosyncline.It is a Tibetan-Tibet truss structure system with complex geological structure,rich mineral resources,favorable geological conditions for mineralization and good prospecting prospects.The leve l of mineral exploration work is relative ly low and it is not easy to carry out on-site manual geological prospecting.Therefore,remote sensing ore prospecting technology is used to predict the prospecting area of mineralization in Jiulong County.Select Jiulong C ounty,Ganzi Tibetan Autonomous Prefecture as the study area,use Sentinel-2A as the remote sensing data source,preprocess the image,combine the spectral mechanis m and alteration of the Sentinel-2A data to represent the rock spectrum characterist ics of the rock,and adopt the classical band ratio method and The principal component analysis method extracts the information of mineralizat ion and alteration anomalies in Jiulong County,and through geological interpretation of remote sensing,uses GIS mult i-source information integration technology to analyze the spatial re lationship between the extracted alteration information and formations,rock masses,and structures,as well as known Based on the coincidence of mines,a remote sensing ore prospecting model based on Sent inel-2A data was establis hed and the prediction of metallogenic prospects in the study area was carried out to provide reference for the follow-up mineral resources exploration work.Using the SN AP software and Sen2 C or module introduced by ESA,the Sentinel-2A image was corrected for atmospheric underlay s urface.The characteristics of the four typical spectral features of the study area were compared and analyzed.The data was imported into the EN VI software and geometrically corrected.,resampling,image mosaic and cropping,interference with the ground mask and other pretreatment operations.Through the pre-processed Sentinel-2A data,comb ined with the particular ity of the Sent inel-2A band and the characteristics of the spectral curves of the major alteration minerals,the band ratio ratio method Band 12 /Band 11 was used to extract information of potassium alterations and anomalies.Banding ratio method Band 11/Band 2 is used to extract siliconization type alteration anomaly information,and 3,4,8 and 11 band combinations are used for princ ipal component analysis to extract informat ion on ironification type alteration anomalies.Bands 3,5,11 and 12 are used.The combined principal component analysis method extracts sericit ization type alteration anomaly information,extracts kaolin alteration anomalies using band ratio method Band 11/Band 8a,and uses band ratio method Band 12/Band 8+Band 7/Band 4 to extract carbonic acid.Salt alteration anomaly information is extracted using the princ ipal component analysis of the 3,6,8 and 11 band combinations for the informat ion of abnormal alterations of the helicoids.Through the comparison and analys is of the previously collected and vectorized geological,mineral resource distribution,rivers,traffic roads and other data,the GIS mult i-source information integration technology was used to superimpose the extracted seven mineralization alteration anomaly informat ion and vectorization data.Analys is and buffer analys is have led to the discovery of four potent ial metallogenic prospects in the study area.Fina lly,a remote sensing ore prospecting model based on Sentinel-2A images in high mountainous areas has been summarized to provide references for the use of “sentinel” data in the field of geosciences.