Integration And Application Of ASTER Data And Geochemistry

Tashkurgan in Xinjiang is one of the important areas where iron deposits are developed in Northwest China.The"Pamir type"iron deposits are widely developed in the area,and the metallogenic prospect is good.However,due to the poor natural conditions in this area,it is relatively difficult to carry out field geological work.The comparative study of remote sensing and geochemical characteristics will be an attempt to carry out metallogenic prediction in this area.Based on the remote sensing data of Tashkurgan area in Xinjiang,combined with the geochemical data of ore-forming related rock mass,stratum and whole rock samples collected during the field geological survey and the zircon U-Pb chronology of some rock mass.This study excavates the relevant information of mineralization（remote sensing image characteristics,rock mass lithology and intrusion age）,and delineates the prospective area of iron ore on a small scale.（1）Based on ASTER Remote sensing data,the relevant information of mineralization and alteration in the study area is extracted.On the one hand,the classification map of alteration anomalies of iron stained and hydroxyl containing minerals is extracted by principal component analysis.On the other hand,the mineral composition related to Fe³⁺,silicate and carbonate was identified by multi band ratio method,and the surface lithology was preliminarily identified and analyzed.（2）Whole-rock geochemistry and LA-ICP-MS zircon U-Pb chronology were conducted for the intrusions in the study area.The results show that the Mesozoic magmatic rocks（195.3-112.4 Ma）in the southwestern part of the study area have lower Si O2 content,are dominated by granodiorite,and have higher Mg O and T（Fe O）contents and V,Cr,Co,Ni,Cu,and are closely related to Pamir-type iron mineralization spatially,while the Cenozoic（13.3-10.7 Ma）intrusives located in the southern part of the Ta’axi Fault are relatively similar to the granites that occur in the skarn-type iron ore deposits in the region.（3）Comprehensive spatial analysis of prospecting information on GIS platform.The correspondence between the regional rock mass distribution,rock mass lithology and age and the spatial distribution after the superposition of remote sensing data is discussed,and four iron ore prospecting targets are delineated,which are generally located near both sides of Ta’axi fault.The A4 target area located on the southwest side of Ta’axi fault,which is obviously different from the known distribution area of iron deposit.The result provides a new direction for further exploration of iron deposit in the study area.The research shows that ASTER Remote sensing data and geochemical data can correspond in space.