Evolution of Tectonic Stress Field and Uranium Mineralization in the Baimadong Uranium Deposit,Guizhou Province
The Baimadong uranium deposit is the unique uranium deposit with industrial value and systematically exploited in Guizhou,which has made important contribution to the development of nuclear industry in China.Since 1980s,many exploration and research works have been carried out in the depth and edge of the pit to enlarge the uranium resources,but the prospecting effect is not ideal.According to the existing research,the ore area and the ore deposit structure have the important control function to the Baimadong uranium mineralization,this research takes the Baimadong deposit as the research object,through the joint fissures statistical survey work,to reconstruct and restore the tectonic stress field,analyze the relationship between tectonic evolution and uranium mineralization,and discuss the characteristics of migration,accumulation and diffusion of uranium mineralization under tectonic stress.The results of the study show that,the regional tectonic stress field related to uranium mineralization and ore-controlling can be divided into three stages.The first stage of tectonic stress field was formed under the north-south horizontal compression during the Caledonian Duyun Movement,which formed the NE and NEE-trend structure and controlled the distribution of uranium mineralization.The second stage,the strongest one in regional,formed the Xiniudong fault and the main compressional surface of the Yangshui anticline;during this stage,two sub-stages of local low-order tectonic stress field combine the NW-trending and the NW-trending folds to form ideal ore-host space.The third stage tectonic stress field dextrally compressed the study area with EW trend,which remade and strengthened the previous tectonic framework.In addition,the Himalayan movement inherited the structural pattern of the third stage and reactivated the W-E trend tectonic belt in the central Guizhou;the deep ore-forming fluids flowed along the Baimadong fault,and the layered and lenticular uranium ore bodies were formed under favorable physical chemistry conditions.The Baimadong uranium deposit was formed by multi-stage tectonic activities.The future uranium prospecting work should focus on the intersection of the NE-trend fault and the near EW-trend regional fault in the central Guizhou;in particular,it is important to pay attention to the superimposed part of the buried NE-and NW-trend fold formed under multiple tectonic stress field.The exfoliation structure and interlayer compression fracture zone in the complex position are favorable for uranium prospecting.
Baimadong uranium depositconjugate jointsTectonic evolutiontectonic stress field
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