Abstract:

Gravity anomalies can well reflect information of the rock under the ground. There is a close relationship between distribution features of sandstone-type uranium deposit with gravitational field. Sandstone-type uranium deposit is mainly distributed in the second step regions of Bouguer gravity in China. What’s more，most of sandstone-type uranium deposits lie at the gravity gradient belt, which are close to the high-value gravitational field area. Based on the ore-formation mechanism of sandstone-type uranium deposit, analysis of features of tectonic evolution and rock of the major uranium-bearing basins, it is considered that subsequent relatively stable tectonic setting is beneficial to occurrence of sandstone-type uranium deposits in uranium-bearing basins of the second step regions. Orographic uplift benefits the denudation of uranium-bearing rock and migration of groundwater bearing oxygen and uranium, and faults have also played important roles in formation of the sandstone-type uranium deposit. Geographical changes cause the gravity field gradient. Structure fractures and composition changes of formation rock may induce disturbance of gravity anomaly contour lines. Therefore, the variation of gravity can be used to predict target areas of sandstonetype uranium deposit exploration. Taking Qianjiadian uranium deposit in Songliao basin as an example, this study discusses the correlation between gravity field characteristics with sandstone-type uranium deposits, reflecting its practical application.

Key words: gravity field, sandstone-type uranium deposit, interlayer oxidation zone type, redox transitional zone, mineralization condition