| Heidewula area is located in Dulan County,Qinghai Province.The geotectonic position is located in the Haideguole area and Qiuliniulisheng area of the East Kunlun orogenic belt,connected with the Qaidam block on the top and the Bayankala orogenic belt on the bottom.Due to the high terrain,large slope and cold climate in the area,it is difficult and costly to carry out the traditional geological prospecting in a large scale.With the development of computer and aerospace technology,remote sensing technology has increasingly become one of the indispensable prospecting methods.This technology has the characteristics of rapid,low cost and high security.It is very necessary to use remote sensing technology to carry out mineral exploration in the study area.In this paper,using a variety of remote sensing image data,combined with geological data and field verification,the geological information such as stratum and structure is interpreted,and the uranium mineralization alteration information is successfully extracted,which provides a basis for further uranium prospecting in the study area and its surrounding areas.In this paper,GF-1 satellite data and ETM + image data are selected as data sources,and GF-1 data is mainly used for geological interpretation of strata,structures and magmatic rocks in the study area.On the basis of fully understanding the spectral characteristics of minerals,ETM + data is used to extract uranium mineralization alteration information in the study area.The specific research work is as follows(1)The remote sensing image of the study area was preprocessed by geometric correction,radiometric correction and image clipping.The 1:50000 remote sensing geological map of the study area was drawn,with GF-1 data image as the main image and ETM + data as the auxiliary.The geological interpretation work of the study area was carried out,and the strata,lithology and structure of the study area were comprehensively determined and interpreted.At the same time,the geological interpretation images of all aspects were analyzed The characteristics are described one by one.Among them,14 sets of stratigraphic units,7 intrusive rock units,42 linear structures and 2 annular structures are interpreted.(2)After fully understanding the spectral characteristics of altered minerals and the characteristics of each band of ETM + data,on the premise of using mask technology to remove interference factors.The band ratio method is used to extract iron staining and hydroxyl alteration anomalies through etm3 / 1 and ETM5 / 7 bands;the standard principal component analysis method is used to analyze the correlation of each band,and then the standard principal component color composite map is obtained.According to the color,the color iron staining and hydroxyl alteration anomalies can be divided;the eigenvector principal component analysis method is used to select four characteristic bands for principal component analysis Extraction of iron staining hydroxyl alteration anomaly.At the same time,through the evaluation and analysis of the three methods,it is considered that the feature vector principal component analysis is the best method to extract alteration anomalies.(3)The existing geological data,geological interpretation information and the extracted alteration information are superimposed by multi-source information.It is found that the alteration information is highly correlated with strata,lithology and structure;at the same time,the location of known uranium mineralization points is compared with the distribution information of alteration anomaly to determine the accuracy of alteration information extraction;finally,four favorable prospecting locations are divided by the intensity and area range of alteration anomaly. |
PDF Full Text Request