Remote Sensing Geological Characteristics And Prospecting Prediction Of Porphyry Type Cu-Au Deposit In The Western Part Of Chagai Area,Pakistan

The Chagai porphyry copper belt in Pakistan is located in the Tethys metallogenic domain,with frequent magmatic activities and good geological conditions for forming porphyry Cu-Au deposits.The Reko Diq and Saindak deposits have been found.However,due to the influence of natural conditions,security situation and other factors,mineral resources exploration,development and utilization degree is low.Therefore,this paper takes the western part of the Chagai area of Pakistan as the study area,interprets the lithology and structure of the study area based on multi-source remote sensing images,extracts the alteration information of typical ore deposits,establishes a remote sensing prospecting prediction model,and defines favorable oreprospecting areas based on this,and analyzes the ore-forming characteristics and prospecting potential of the western part of the Chagai Area.It provides information support for the investigation and evaluation of mineral investment and resource potential of Chinese enterprises in this area.The main achievements are as follows:(1)Multi-source remote sensing images of Landsat(TM、ETM、Landsat 8),ASTER(Advanced Spaceborne Thermal Emission and Reflection Radiometer),GF-1 and GF-2 in the study area were corrected,image fusion,clipping and enhancement processing,and suitable band combinations were selected to enhance lithology information,the 1:250,000 and 1:50000scale remote sensing geological interpretation mark were established respectively,the remote sensing geological map was prepared by visual interpretation,and the original geological map was updated.(2)According to alteration zoning of porphyry copper ore and spectral characteristics of typical minerals,principal component analysis was carried out on ETM and ASTER images by selecting appropriate band combination,and the alteration information of iron staining,sericitization,kaolinization and propylitization in the study area was extracted to analyze the spatial distribution characteristics of remote sensing alteration information.The extraction results are in good agreement with the known deposits.The known deposits in the area all have strong sericitization accompanied by propylitization.(3)Based on the metallogenic geological background,image features of typical ore deposits and alteration information extraction results,the remote sensing prospecting model of porphyry deposit in the western part of Chagai area is established.That is,the host rock mass is bluish gray in ETM741 image,pink in ASTER468 image and bright cyan in ASTER RBD865 image.It has strong sericitization and local kaolinization,and the contact zone with surrounding rock has the characteristics of propylitization.(4)Based on the established remote sensing prospecting model,more than 10 prospecting prospects were delineated,and altered rock mass was found in some prospects during field inspection.By comparing the measured spectrum of rock samples in the field with the USGS standard spectrum library,the absorption characteristics of the sample spectrum and the standard spectral curve are highly similar,which further confirms the accuracy of information extraction results and the feasibility of remote sensing technology in guiding prospecting in this area,and provides data support for the next exploration work.