松辽盆地南部开鲁坳陷姚家组砂岩物源示踪研究OACSTPCD

For the potential prediction and the evaluation of in-situ leachable sandstone type uranium deposit,the source of ore-bearing sand body it is the key factor.In this paper,the microtrace,rare earth elements and zircon chronology of sandstone samples from the Upper Cretaceous Yaojia Formation in the southern margin of Songliao Basin was studied for the tracing the source.The results showed that the content of REE is 100.08×10-6～134.06×10-6,which is characterized by the enrichment of LREE,flat of HREE and moderate negative Eu anomaly.The REE pattern of all samples are highly consistent,indicating that the source of Yaojia Formation came from the same source system.According to ∑REE-La/Yb,Hf-La/Th,Zr/Sc-Th/Sc and Cr/Th-Th/Sc diagrams combined with the microscopic characteristics of sandstone,the source rocks was found to be felsic rocks.U-Pb dating of detrital zircon showed that the concordant ages of the zircons are mainly distributed in three ranges,110～180 Ma,230～280 Ma,1 695～2 171 Ma.With the lithostratigraphic division,characteristics of trace and rare earth elements,age of magmatic rocks and regional tectonic evolution,the sediments of Yaojia Formation was believed to be originated from Ulanhot area in the southern part of the Greater Hinggan Mountains.