关键词: 准噶尔盆地南缘, 侏罗系—白垩系, 物源体系, 演化特征

Abstract: The oil and gas exploration potential of the Jurassic-Cretaceous reservoirs in  eastern part of the southern margin of Junggar basin is huge, but the limited understanding of its provenance conditions and sedimentary background evolution seriously restricts the subsequent oil and gas exploration and development. In this study, the source characteristics of the Jurassic-Cretaceous sediments in eastern part of the  southern margin of Junggar basin are determined and the evolution process is restored through the analyses of sandstone clastic composition, conglomerate gravel composition, heavy mineral type and combination, paleocurrent characteristics, and stratigraphic lithology proportion, and the evolution process is restored combined with the regional tectonic evolution background: Olutio the Bogda Mountains did not uplift in the Early Jurassic, and the provenance system of the quasi-southeast segment was controlled by the northern Kelamey Mountains and the southern Tianshan Mountains；The original sedimentary boundary in the southern part of the study area is far away from the current basin boundary. In the Middle Jurassic, due to the uplift of the surrounding mountains and the influence of Yanshan movement, the Bogda Mountains began to uplift and gradually exposed to the surface, which had a certain impact on the provenance system of the southeast section, however, from the Late Jurassic to the Early Cretaceous, the Bogda Mountains continued to uplift and eventually became the dominant source area in the southeast；At the same time, the uplift of Kelamey Mountains increased from the Late Jurassic to the Early Cretaceous, which enhanced its supply capacity. On the whole, from the Early Jurassic to the Middle Jurassic, the quasi-southeast segment was jointly affected by the southern Tianshan provenance system and the northern Kelamey provenance system. During these dimentary period of the Middle Jurassic-Early Cretaceous, the southern Tianshan provenance system, the northern Kelamey provenance system and the Bogda provenance system coexisted, however， their influence on the Jurassic-Cretaceous system in the southeast segment is different.  

Key words: southern margin of Junggar basin, Jurassic-Cretaceous, provenance system, evolution characteristics