Abstract:Based onrecent drilling, seismic, and aeromagnetic anomalies, a systematic study was conducted on the location distribution, development time, formation and evolution, and reservoir control effects of the Ordovician Zhidan Hengshan ancient uplift in the Ordos basin. The results indicate that the Zhidan Hengshan ancient uplift is distributed in an arc shape in the Zhidan, Hengshan, and Yulin areas. It is a compressional uplift that developed during the early stage of the fifth Member of the Ordovician Majiagou Formation. Under the influence of compressive stress, the uplift’s axis gradually narrowed, its amplitude increased, and it migrated northwestward in an arc- shaped pattern, reaching its maximum development during the deposition of the fifth and sixth sub- sections of the Majiagou Formation. The Zhidan Hengshan ancient uplift displays a superimposed relationship with the Wushenqi Jingbian ancient uplift. Their development is controlled by a complex interplay between basement structural attributes and the peripheral structural background. Both uplifts are localized within weak structural zones where the crystalline basement of the basin intersects with the Ordos landmass and the Kongziyan belt. The main body of the Wushenqi Jingbian ancient uplift is located along one side of the Kongziyan belt, connecting with the Yimeng ancient landmass to the north, which formed during the Precambrian period. Compressive stress in the northern part of the basin uplifted the crystalline basement along the Kongziyan belt, which is overlaid by the edge of the Great Wall series trough. The main body of the Zhidan Hengshan ancient uplift is located along one side of the Ordos block, connecting with the Qingyang ancient uplift to the south. Its formation is primarily related to the transition from passive to active continental margins during the Middle- Late Ordovician period. Continuous compression on the southwestern edge of the basin remotely uplifted the Ordos block towards the Kongziyan belt. The interconnected Wushenqi Jingbian and Zhidan Hengshan ancient uplifts control the accumulation of natural gas beneath the Ordovician salt layer, making them worthy of further exploration and attention.