SEDIMENTARY CHARACTERISTICS AND URANIUM MINERALIZATION OF THE YAOJIA FORMATION IN NORTHERN SONGLIAO BASIN

On the basis of geologic conditions, this article analyses the uranium metallogenic conditions of the Yaojia Formation in the northern part of Songliao Basin. The investigation shows that extensively developed rivers and deltas in Yaojia Formation form passways and reserve space for uranium metallogenic fluids. The three mountains with uraniumrich granite, which surround the Songliao Basin in south, north and east, serve as uranium source. The areas near the structural denudation windows, which were formed by the compressive stress from Yanshanian orogeny and Himalayan orogeny, are favorable for the enrichment of uranium. The basin, characterized by infiltration type of artesian basin, has a good hydrogeological condition. During the sedimentation of Yaojia Formation, the paleo-environment was mainly presented in arid, semi-arid or warm climate, which is helpful for the pre-enrichment or syndepositional mineralization of uranium in the strata.