Evidence of early passive diapirism and tectonic evolution of salt structures in the western Kuqa depression (Quele area), southern Tianshan (NW China)

Abstract

High-resolution remote-sensing imagery, seismic, well-log, magnetotelluric data, and field observations are integrated to investigate the Cenozoic salt-related structures in the western Kuqa depression (Quele area), southern Tianshan, NW China. Field observations of Oligocene to Miocene halokinetic sequences suggest early passive diapirism was developed in the Kuqa depression. More evidence also indicate that the progradation of the Paleogene Quele alluvial fan and basement steps have important controlling roles on the formation of the early salt structures. Rock salt was driven by the progradation wedge to flow basinward, then basement steps would provide resistance and hold the positions of early salt structures. On the basis of the kinematic model, it is suggested that the early Quele salt wall, which acts as a stress concentration zone, is deformed to the Quele salt nappe during the subsequent regional shortening, and controls the changes of along-strike geometries in the Quele area.