Sedimentary environment analysis of Yaojia formation--the ore-hosting stratum of Qianjiadian uranium deposit

Qianjiadian uranium deposit is the first uranium deposit discovered in Songliao basin. In this paper, the sedimentary environment of Yaojia formation, the ore-hosting stratum of Qianjiadian uranium deposit and its relationship with uranium mineralization are studied from several aspects such as lithological combination, sedimentary structures, logging curves, thickness ratio of sandstone layer to mudstone layer, sedimentary petrology and petrological geochemistry. The sedimentary features are characterized by the average value 5.0 between thickness ratio of sandstone layer to mudstone layer of Yaojia formation, and typical tabular cross bedding and trough cross bedding. The lithology of Yaojia formation is mostly composed of intermediate to fine-grained sandstone and mudstone with less conglomerate, and the debris grains have moderate sorting and roundness. These indicate that the source area is far, and that the sediments underwent long-distance transportation before deposition. The large scale and stable extension sand body of the Yaojia formation demonstrated the sedimentary features ora large sedimentary basins. Therefore, the sedimentary environment of Yaojia formation in the study area should be far-sourced sandy braided stream in the united great Songliao basin. The uranium mineralization of Qianjiadian deposit is mainly controlled by the sand bodies of channel-bar and point-bar subfacies, and the scale of the mineralization is closely related to that of the sand bodies. (authors)