Analysis of the tectonic stress field in the Xiangshan uranium ore field, Linchuan area, Jiangxi, China

The Xiangshan uranium ore-field is the largest volcanic-related meso-epithermal deposit in China and the uranium-mineralization is tightly controlled by fault activities. As exploited and doveloped for many years, the ore-reserve resource of the deposit is in current crisis, although the potential reservoir is probably great. Therefore, the study in ore-field structures is imminent to provide scientific guidance for ore-prospecting in the deep and surrounding areas. This paper mainly presents field measurement results of joints and fault scratches to identify features of tectonic activities and the principal stress direction, using traditional and modern methods in tectonic stress field research. Stages and times of the tectonic stress field are also determined based on successively superimposed deformation relations and diagenesis ages of volcanic rocks. The result showed that the tectonic stress field in the Xiangshan ore field can be divided into three stages and six periods. Basement deformation and two phases of volcanic activities occurred before the metallogensis, and main mineralization stages could be divided into three periods, and uranium ore bodies were locally dislocated by fault activities after the formation of ore-deposits. Characteristics of different phases of tectonic activities and its relationship to the uranium mineralization were additionally discussed, suggesting that the uranium mineralization was consistent with the evolution of the regional tectonic stress field. Favorable structural ore-forming areas for grade-rich ore-bodies in the Xiangshan uranium ore-field were further pointed out.