1. College of Earth Sciences，Jilin University，Changchun 130061，China; 2. Jilin Province Key Laboratory of Oil Shale and Symbiotic Mineral，Jilin University，Changchun 130061，China

The 1st Member of Qingshankou Formation in Songliao Basin is composed mainly of dark- colored mudstone，and developed in good quality oil shales． Based on systematic sampling，the geochemical analysis of the mudstone from Well NGN1 in the southeast uplift of Songliao Basin，was made by the authors． The results show the SiO₂ content ranged from 44. 88% to 57. 75%，K₂O generally higher than Na₂O in content，and the parameterof (MgO + Fe₂OT₃ ) ranged from 4. 5% to 10. 01%，which indicates that the mudstone contained a relative quanti- ty of potassium- bearing mineral and a certain amount of femic constituents． The PAAS- standardized distributive curves of trace elements show the same enrichment and depletion trends among different samples，which suggests that the mudstone had a dominating provenance． The chondrite standard curve of rare earth elements reveals the enrichment in light ＲEE and negative anomalies of Eu，which shows the provenance of the mudstone came from the upper crust． The mudstone weathering and alteration index ranged from 48 to 62 and Th/U ratio mainly ranged from 1. 48 to 4，both of which suggest that the provenance had underwent a low weathering processes． The Th/Sc- Zr/Sc diagram shows that these mudstones were mainly controlled by source rocks，and their clastic deposits had not suffered sedimentary recycling，which means the provenance characteristics and tectonic setting of the mud- stones could be judged by the geochemical analysis． On the basis of sourse rocks and discrimination diagrams of tectonic setting，it was concluded that the provenances of the 1st Member of Qingshankou Formation were mainly intermediate- acid extrusive rocks from Mid- Late Jurassic，and also involved in Hercynian and Yanshanian grani- ties． The source rocks were formed in the continental margin orogenic belt and belonged to continental island arcvolcanic series．