The striking connection of Cenozoic thrust sheets in Kalpin fault uplift, Xinjiang, and their formation mechanism

Abstract：Cenozoic nappe structures in the Kalpin fault uplift constitute a part of southern South Tianshan marginal thrust system. The number of nappe sheets is different from place to place, and the corresponding relationship of the nappe sheets in different parts is not clear because of the disturbance of the dip faults, which forms an unique orocline. The Cenozoic orogenic movement of southern South Tianshan is largely characterized by the deformation of the nappe sheets. By means of TM image interpretation and field geological investigation, the structural features at the intersects between the dip faults and the nappe sheets and the minor structures which can show the formation information of the nappe sheets were studied in detail. On the basis of the study, the disturbed nappe sheets in different parts of the uplift were connected successfully and the number of the nappe sheets was identified as well. A tectonic model has been suggested, which holds that the disturbed nappe sheets resulted from folding and fault slipping in the striking direction of the nappe sheets when they thrusted southeast under the NW-striking maximum principal compression stress, and the dip faults originated from the minor faults that occurred in the wings of the folded nappe sheets.