Action of reversal fault structure on sandstone type uranium mineralization in the south of Songliao basin

The faults in the south of Songliao basin suffered multiple distinct tectonic movements and some kinds of reversal structure were developed. At the period of fault subsidence, these structures acted as normal fault. At the period of reverse, they occured thrusting and cause the hanging wall of the faults to form reverse anticlinal belt. Due to the folding and uplifting, scuttle structure of ablation was shaped at some part of the anticlinal belt. Among them, the reversal faults dissected the layers from base rock to Nenjiang group, caused the reductive fluids such as oil, carbon dioxide, coal derived gas migrating upward, which was generated by oil source rock of Shahezi and Yingcheng group from the lower layer. These fluids made the loose red sand body reduced exogeneously and create some gray sandstone which are favour of uranium mineralization. At the same time, the scuttle structure of ablation shaped by the reverse process lead the layer of interest exposed to the air to suffer oxidation and infiltration of urania, which is favourable to interlayer oxidation and mineralization of uranium. (authors)