Abstract: It was believed previously that in Cretaceous of Songliao basin developed 6 large provenances and 11 major river systems. However, a new river system named Yushu river system is discovered by the authors in Dongnan (southeast) uplift, with granite as the mother rock in the Caledonian and Indosinian orogenies in Zhangguangcai mountain. This system developed from Quantou formation to Nenjiang formation is dominated by fluvial and delta deposits. The comprehensive geologic studies show that Yushu river system has great exploration potentials. Its source rocks are mainly lacustrine mudstone of the Qingshankou No.1 member, Yingcheng formation and Shahejie formation, in which Fuyang oil zone is the major target for middle-shallow petroleum exploration. At present, Yushu river system has become an important domain for incremental reserves and production in Jilin oil field.

Key words: Songliao basin, Yushu river system, sedimentary facies, source rock, exploratory potential