Reomote Sensing Alteration Extraction And Metallogenic Prediction Of Porphyry Copper Deposits In Meiduk,Iran

The central volcanic belt of Iran is located in the middle part of the Tethys metallogenic belt,which is rich in mineral resources.It is a typical porphyry type copper mineralization area with great prospecting potential.However,the high altitude,rugged terrain and inconvenient transportation in the central volcanic belt make it difficult for researchers by traditional ore prospecting work.Remote sensing can break through the limitation of traditional prospecting methods,and the extracted mineralization alteration can indicate the existence of ore deposits,which serves for prospecting and exploration.However,the remote sensing alteration extracted by traditional methods often contains a large number of background interference information,which may cover up the relevant information indicating mineralization.Thus,the accuracy of extraction results is low.In this paper,the fractal method is used to extract more accurate alteration anomaly for metallogenic prediction.It can provides a reference for remote sensing prospecting of porphyry copper deposits in metallogenic belt.In this paper,the Meiduk area of Iran is selected as the research area,ASTER remote sensing data is used as the data source,and the characteristic minerals of alteration zoning of porphyry copper deposit are taken as the research object.Principal component analysis is used to extract remote sensing alteration.The method of S-A and C-A is used to process the alteration and classify the anomaly.Finally,with the collected geological background data,the metallogenic prediction prospecting was carried out based on the fuzzy weight of evidence method.The main research contents and achievements are as follows:(1)Remote sensing alteration extraction.ASTER remote sensing data is used as the data source,and the data preprocessing is completed.According to USGS standard spectral library,the remote sensing alteration minerals of porphyry copper was extracted by principal component analysis.(2)Extraction of remote sensing alteration anomaly.In this paper,the S-A fractal filtering method is used to process the extraction results of mineral alteration,and the mineral alteration anomaly and background interference information are separated effectively.The alteration anomaly was classified by C-A method.Contrast the extraction results of fractal method and traditional method,it is proved that the fractal method can effectively enhance the weak alteration anomaly in the low value background area and improve the extraction accuracy of remote sensing alteration anomaly.It can provide more accurate mineral alteration data for metallogenic prediction research.(3)Metallogenic prediction modeling and experiment.In this paper,with the data of mineral alteration,fracture and lithology as evidence weight factors,the fuzzy evidence weight method is used to the metallogenic prediction prospecting of porphyry copper deposit in the study area.And the prospective area is circled in the study area.The location of the prospective area is consistent with the field mining area.It is proved that remote sensing alteration is feasible for metallogenic prediction.