Numerical Simulation And And Metallogenic Analysis Of Structural Reactivation For Lujing Uranium Ore Field In The Central Zhuguang Mountains,South China

Numerical simulation method has been widely used in metallogenic mechanism analysis and metallogenic prediction of hydrothermal deposits because of its advantages of quantifying metallogenic conditions,visualizing metallogenic process and being free from temporal and spatial constraints.In recent years,numerical simulation of mineralization of hydrothermal deposit shows that structural reactivation provides the driving force for the migration of ore-forming fluids,and the dilated area generated by structural reactivation also provides a place for the precipitation of ore-forming materials.Granite type uranium deposit is one of hydrothermal type uranium deposit.As the most important granite type uranium deposit area in South China,Zhuguangshan area has many large granite type uranium deposit fields(beds).The Caledonian,Indosinian,Yanshanian and other intracontinental tectonicmagmatic events developed,and the mineralization of granite-type uranium fields(beds)was closely related to tectonic processes.The NE trending fault structure of Lujing uranium ore field in the middle of the Guangshan Mountains is well developed and has produced multi-stage structural activation since its formation.However,the study of tectonic activation and uranium mineralization in ore field is weak,especially how tectonic activation affects the spatial distribution of uranium ore.In this paper,FLAC3 D software is used to numerically simulate the structural reactivation of Lujing uranium field and several uranium deposits in the ore field.According to the spatial distribution relationship between the dilatant zone generated by structural reactivation and uranium mineralization,this study has obtained the following understandings:(1)The stress direction of structural reactivation determines the spatial distribution pattern of the expansion area,and the occurrence of tensile structural reactivation in the NW direction is the main controlling factor controlling the deposit distribution in Lujing uranium field.(2)In the tensioning environment,the lithologic difference combination of upper and footwall of the fault controls the spatial distribution of the ore body,and the surrounding rock types in contact with the fault include more than three kinds of deposits,which is more conducive to deep uranium mineralization.(3)When the fault dip Angle is less than 80°,the prospecting work should be carried out in the upper wall rock and its deep part of the NE fault.This study reveals the control mechanism of structural reactivation on uranium mineralization,deepen the understanding of controlling factors of uranium mineralization in Lujing uranium field,and provides important theoretical guidance for uranium exploration in Zhuguangshan.