The Application Of Information Extraction And Geodynamic Computational Modeling In Metallogenic Prediction Of Yueshan District

Anqing-Yueshan district, located in the central segment of the Yangtze metallogenic belt, is an important copper district in China, because there is not only the largest Fe-Cu deposit, the Anqing copper deposit, but also a great potential for finding hidden ore deposits. In such setting, metallogenic prediction is closely related to the probing of the tectonic architecture and understanding of the metallogenic geodynamics evolution. In this thesis, the ETM+data of Landsat-7 are computed by the method of contrast enhancement, band ratio and principal component analysis to extract the structure, lithology and hydrothermal alteration information in the Anqing-Yueshan district. For analyzing the ore-controlling dynamic factors, the ANSYS code is used to simulate the pale tectonic stress field of the Yueshan district in the metallogenic stage and the FLAC code is used to simulate the syn-tectonic cooling of intrusions in this district. The main outcomes in this thesis include the following 4 aspects:(1) By computational processing of the ETM+data of the Yueshan district, the structural and lithological information as well as the iron alteration information are extracted. It is useful not only for construction of the geodynamic models but also for the selection of prospecting target and metallogenic prediction;(2) By computational modeling of tectonic stress field, it is demonstrated that the locations of ore deposits are closely related to the tectonic stress field. The areas with the greatest gradient of principal stress, shear stress and differential stress are favorable for metallogeny;(3)Through computational modeling of the syn-tectonic cooling of intrusions, it is discovered that the high dilation zones are mainly distributed along the contact zones of diorite intrusions with their host rocks of carbonates. It is demonstrated that the dilatant deformation is critical for controlling ore formation;(4) The district metallogenic prediction is conducted by synthezing the results of ETM+information extraction and geodynamic modeling. The Jixianguan, Duxiushan and Hongpuzhen are the target areas most favorable for finding hidden ore deposits.