Abstract: Because of the blind area existed in middle-deep seismic images, the understanding of the structural characters in Gumudi area is still unclear up to now. In view of obvious differences of density and resistivity of strata in different ages in southern margin of Junggar basin, there are good geophysical conditions for gravity-magnetic-electric prospectings. The study shows that Gumudi structure belongs to front structure of piedmont folded thrust belt in Bogda mountain. Controlled by step fractures, it is characterized by vertical multi-strata structures: the shallow strata assume tight overthrust inverted anticline; the middle strata appear in roof-like fault block controlled by step overthrust faults, and the deep strata are buried hill drape-like thrust anticline. The gravity anomaly displays that the west pericline of Gumudi anticline could be a complete anticline. It is concluded that the middle-deep structures and the west pericline in Gumudi area are favorable targets for petroleum exploration.

Key words: Junggar basin, southern margin, Gumudi structure, structural type, gravity-magnetic-electric prospectings