Remote Sensing Identification And Application Research Of Fault Structure In Longshoushan Uranium Metallogenic Area

Longshoushan area is an important uranium metallogenic area in China,whose mineralization is closely related to structures.Because of the complex topography in the area,it is difficult for traditional geological survey methods to systematically and comprehensively identify the faults in the area.Although remote sensing technology can make up for this shortage,the research on structures based on remote sensing in this area mainly used visual interpretation to identify the features of faults,and has not systematically studied the mechanical properties of faults in this area and their relationship with uranium mineralization.Based on GF-2 images,Landsat 8 OLI images and ASTER GDEM,this paper studied the automatic extraction of lineaments and the image analysis of mechanical properties of faults,and applied it to the identification of structures in Longshoushan uranium metallogenic area.The geological structures and their relationship with uranium mineralization was systematically and deeply studied.The main results and understandings are as follows:1.The influence of image type and spatial resolution on the automatic extraction of lineaments was studied.It is found that PC5 of OLI image(B2 ~ B7)after principal component transformation is beneficial to structures recognition.The low spatial resolution PC5 is suitable for extracting the main structures,while the higher spatial resolution(10m)image generated by OLI and GF-2 fusion is suitable for extracting the secondary structures.2.After deeply studying image processing technology,the multi-scale image set was constructed.Namely,color synthesis,principal component analysis and image fusion were used to construct low,medium and high-scale images,which are contributed to interpretation of faults and analysis of their mechanical properties.3.Based on the LINE module of PCI Geomatica and the removal of interference from road,ridge and image edge,the lineaments of the study area were effectively extracted,and a semi-automatic extraction method of remote sensing fault structure was established,including image selecting,extraction of main and minor linear traces,interference removal and linking.4.Combining with the knowledge of geology,through the detailed study of multi-scale image data set,the mechanical properties of the main faults in the study area were analyzed.On this basis,the image characteristics of faults with different mechanical properties were preliminarily summarized in combination with previous achievements.5.Based on the density and fractal characteristics,combined with geological data,it is considered that uranium mineralization in the study area is controlled by rock mass contact zone and structure.The favorable areas for uranium deposit are mainly located in the transition zone of high and low fractal dimension values and density values.At the same time,the relationship between the orientation and mechanical properties of the faults and the known uranium deposits was analyzed.It is considered that the uranium deposit in Longshoushan area was formed in the relaxation zone of the early NWW and NW-trending compressive fracture zone caused by the strike-slip action of the ~SN-trending torsional fault in the later stage.