Abstract: A direct genetic affiliation was speculated upon the formation and evolution of the foreland depression in the northwestern part of the Junggar Basin and the uplifting and thrusting of the West Junggar orogenic zone on the basis of geological, geophysical and geochemical data. The northwestern part of the Junggar Basin was developed on the ground of the Early and Middle Palaeozoic oceanic crust. This part of the basin was a residual oceanic basin during the Middle Devonian, a fore-arc residual oceanic basin during the Late Devonian to the Late Carboniferous, and a foreland basin during the Permian. The study of the geochemistry of the geofluids has disclosed that the generation, migration and enrichment of oil and gas in the Karamay oil field have a genetic link with the various geological processes, especially those associated with the geofluids during the basin-range transition in the studied regions.