Lacustrine storm deposits of Qingshankou Formation in southern Songliao Basin

On the basis of core observation,grain analysis and thin section studies,the lacustrine storm deposits in Qingshankou Formation in southern Songliao Basin are studied.The main types of storm deposits characteristics are identified,including hummocky cross-stratification,surface of scour,gutter cast,truncated structure,water-escape structure,bioturbation etc.Grain analysis indicates that saltation population is central yet suspension population is minor in storm deposits.Similar Bouma sequence is abstracted from the storm deposits of Qingshankou Formation.There are two provenances for storm deposits in this area,in which one comes from(fan) delta,and the other comes from beach and bar of shallow lake.Based on sedimentary features and transported instance,storm deposits are divided into autochthonous tempestites and allochthonous tempestites.