关键词: 徐家围子, 徐西?徐南地区, 沙河子组, 物源体系, 沉积体系

Abstract: Fine provenance analysis and clear provenance system characteristics are of great value and significance for restoring the type and distribution characteristics of paleosedimentary system and searching for sandstone enrichment areas. Based on the data of heavy minerals, seismic attributes,sand⁃land ratio and palaeogeomorphology, this study systematically analyzed the characteristics of the ancient provenance system of Shahezi Formation in Xuxi⁃Xunan area from different perspectives and levels. The study shows that the Shahezi Formation in Xuxi⁃Xunan area mainly develops two provenance systems, east and west. The provenance of the Xuxi fault terrace zone in the west is the main provenance direction of the study area, with greater provenance intensity and wider influence. The eastern provenance has a small influence range, mainly concentrated near the north and south ends, and is the secondary provenance direction. Generally speaking, the provenance direction of the study area has the characteristics of pointing from the east and west to the middle. The Shahezi formation in the study area mainly develops fan delta, Braided river delta and lake sedimentary system. The fan delta deposits are mainly controlled by the provenance of the Xuxi fault terrace belt in the west and distributed evenly along the fault terrace belt. The braided river delta deposits are controlled by the eastern provenance, mainly developed near the uplift at the north and south ends. The provenance influences and controls the development types and plane distribution of the sedimentary system from the source.

Key words: Xujiaweizi, Xuxi?Xunan area, Shahezi formation, Paleo?provenance system, Sedimentary system