The basin-range coupling under the regional compressional regimes: Examples from the Hexi Corridor Basin and North Qilian Mountains

The coupling relationship between the Hexi Corridor Basin and North Qilian Mountains is discussed in terms of tectonic and depositional records in the study areas from the Cenozoic onwards. The basin and mountains initiated on the ground of paraplains during 38 Ma B.P. The basin area increased due to the compressional regimes of the study areas and disintegration of I-order planation surfaces during 38-17 Ma. After that, the southern margin of the basin was constantly uplifted and the depocenter migrated northwards. The northward prograded II-, III- and IV-order planation surfaces appeared during 4.96-3.66 Ma, 0.93-0.84 Ma, and the latest stage of the middle Pleistocene to the early stage of the late Pleistocene, respectively. The movement styles of the basin-range structures include piggback, tilting and ramping types. The former one may act as the main style in early stages of the basin evolution, whereas the latter two were active during 0.93-0.84 Ma. The tilting-type movement is responsible for the formation of the transverse uplifts within the basin while the ramping-type movement is manifested in the uplift of the Longshou Mountains and Heli Mountains in the northern part of the basin.