Study Of Remote Sensing Information Extraction And Prospecting Direction In L?liangshan-Shuangkoushan Area,Qinghai Province

The study area is located in the western of the ultrahigh-pressure metamorphic belt in the northern margin of the Qaidam Basin,characterized by a number of deposits such as the Yukabashi mine,the Yuka rutile deposit,the Yuka gold deposit,the Luliangshan copper-gold deposit,and the Shuangkoushan silver-lead-zinc deposit,and also is an important mining area in Qinghai Province.The bedrock of most parts of the research area is exposed,and somewhere is covered by the Quaternary sand sediments.The exposed area of the bedrock is strong in physical weathering,belonging to the semi-desertized landform landscape,the altitude is pretty high and has steep terrain conditions,so this kind of environment will not be conducive to geological workers'understanding of geological bodies and structural information in the area.However,the climate in the region is arid and the overall vegetation coverage is low,which is beneficial to obtain alteration information and stratigraphic lithologic information in the study area by using remote sensing image data,therefore improving the understanding of the target geological body and alteration information about the whole region.In order to assist the geological exploration work of the staff and enrich the geological information in the area,this paper used two kinds of multi-spectral data of OLI and ASTER and a high spatial resolution data of SPOT6,and adopts the band combination and visual interpretation method to interpret the stratigraphic lithology in the study area through ENVI5.3 software platform.Based on two kinds of multi-spectral data,we extract extract the alteration information of the study area by the principal component analysis method?PCA?,and have analyze the alteration information with the existing geological and geochemical data in the study area.The main results obtained are as follows:?1?The approximate discrimination of the basic-acidity degree of the main geological bodies in the area was completed.Based on the ASTER thermal infrared spectroscopy data,the SiO₂ content of the rock in the study area was calculated by the SiO₂ inversion formula studied in the previous study.The SiO₂ content classification map and lithology classification map based on the calculation results were used in the area.We found that the lithologic basicity-acidity of geological bodies basically corresponds with The SiO₂ content classification map which was calculated,which confirms the rationality of the application of ASTER thermal infrared data.?2?Quickly extract eclogite and structural information in the study area.The SPOT6high spatial resolution image is combined with the ASTER multispectral data to obtain a new remote sensing image with high spatial resolution and multi-spectral resolution.The false color image obtained by band combination of the new data greatly improves the ability to interpret lithological structures compared to the original SPOT6 data.This study analyze and compared the characteristics of eclogites in the field and SPOT6 true color images,and finally distinguished eclogites which are basic,gray-black,long strip-shaped and lenticular from the light gray-white medium acidity Yukahe group,and delineated two eclogite prospecting targets.?3?Extracting various types of alteration information in the area and delineating several prospecting targets.Based on the multi-spectral data of OLI and ASTER,four kinds of alteration information such as iron corrosion alteration,hydroxyl alteration,carbonate alteration and silicidation were extracted from the whole study area.The information of carbonate alteration and silicification alteration was mainly Based on ASTER data acquisition.After superimposing and comprehensively analyzing various kinds of alteration information with geological geochemical information,we found that the extracted alteration information has a good correlation with the stratigraphic lithology and geochemical information of the known deposits in the study area.And we also delineated two new hydrothermal deposit prospecting targets by the Similar comparison method,indicating that the alteration information extracted based on multi-spectral data is reliable.