Research On Alteration Information Extraction Based On Sentinel-2A Satellite Data

Mineral resources are the important guarantee of the national resources strength and economic strength.Therefore,the demand for mineral resources is increasingly urgent.Remote sensing technology has many advantages such as long-distance exploration,high timeliness and cost-effective,so it has been widely used in geological prospecting.With the development of the times,remote sensing technology is also constantly improving and improving.Because of the alteration of surrounding rock is often accompanied by the occurrence of mineral resources,it is an effective method to extract alteration information by remote sensing image.In this paper,sentinel-2a satellite data are used as data sources,Beiya gold mine and its surrounding areas in Heqing County,Yunnan Province as the research area,and the research experiment of information extraction of mineralization alteration is carried out.The sensor-2a satellite data is preprocessed,and the image geometry atmosphere correction,resampling and band fusion are carried out;The spectral characteristics of different types of alteration in sentinel-2a satellite data are analyzed.The best band combination suitable for extracting alteration information from sentinel-2a satellite data is selected,and a series of data processing is carried out to extract the better alteration information.Based on the regional strata,magmatic rock characteristics and regional structure,the metallogenic model of Beiya gold deposit is analyzed.On this basis,the distribution characteristics of the mineralization alteration information in the study area are analyzed.The favorable metallogenic areas in the study area are found by combining the different classification of the alteration information and the geological background of the fault structure,stratigraphic geomorphology and magmatic rock distribution.The main achievements are as follows:(1)In this experiment,a new technology system of extracting information of mineralization alteration based on sentinel-2a satellite data,which includes mask denoising,principal component analysis,threshold cutting,density segmentation,classification extraction and filtering smoothing,is established.The best band combination of iron dye and hydroxyl alteration extraction is found by the characteristics of sentinel-2a satellite data.(2)The ore-forming model of Beiya gold deposit is analyzed.It is a multi-genetic and multi-type gold polymetallic deposit with complex mineralization.The main surrounding rock alteration is carbonate rock alteration of Beiya formation,which makes the chemical properties of elements in the sedimentary environment very active after hydrothermal mineralization,which is conducive to the formation of gold deposits by hydrothermal precipitation.(3)By using the method of multi information comprehensive analysis,the traditional geological information and the extracted mineralized alteration information are combined,and the superimposed analysis is carried out on GIS platform.The multiple alteration information anomaly areas in the research area are further delineated,and the abnormal areas are classified and sorted comprehensively,and the favorable metallogenic areas in this area are predicted quickly,economically and effectively.The data processing process of alteration information extraction proposed in this paper has a certain auxiliary effect on the development of mineral exploration in the region.