Abstract: Based on the analysis of seismic reflection characteristics, regional structure and core data, it is believed that the erosion trough developed in Paleozoic strata of Mangar sag in Tarim basin was resulted from contour current. The deposit primarily consists of contourite with a small amount of turbidite. This contourite is near the sourre rock and is composed of well-developed sandstone with stable shale cap. Therefore it is of hydrocarbon prospectiveness and can be regarded as the object for exploration in this area.

Key words: Tarim basin, Mangar sag, Paleozoic, Erosion action, Contourite, Hydrocarbon-bearing series