Abstract: The Fuxian Area of the southern Ordos Basin is rich in oil and gas resources. This area is characterized by the development of small-displacement strike-slip faults, which play an important controlling role in the migration and accumulation of oil and gas. Through detailed interpretation of 3D seismic data in the Fuxian Area, combined with previous research results and oil and gas exploration practices, the development characteristics and evolutionary causes of strike-slip faults in the Fuxian Area were explored. The study shows that small-scale and small-displacement strike-slip faults are mainly developed in the Fuxian Area of southern Ordos Basin, with a low degree of development. Both horizontal and vertical displacements of the faults are not significant. On the profile, the faults are mainly characterized by steep upright, flower-like, and "y"-shaped features, while on the plane, the faults exhibit multiple orientations and a chaotic distribution pattern. The fault activity can be divided into four stages, namely right-lateral tensional activity during the Caledonian period, right-lateral strike-slip activity during the late Hercynian period, inherited strike-slip activity during the Indosinian period, and left-lateral strike-slip activity during the Yanshanian period to the early Himalayan period. The evolution of the faults is mainly influenced by the basement faults and the multi-stage tectonic activities in the southern part of the basin. The activation of the basement faults and the attenuation of the tectonic stress transmitted from the basin margin to the interior of the basin result in the fault activity in the study area being characterized mainly by small-displacement weak strike-slip motion. This study provides a theoretical reference for the study of oil source faults and exploration practices in the Fuxian Area.

Key words: strike-slip fracture, tectonic features, tectonic evolution, Fuxian Area, southern Ordos Basin