Stratigraphic and Sedimentologic Records of the Uplifting of the West Kunlun in the Cenozoic

The uplifting of the West Kunlun, or more exactly the relative motion between the West Kunlun and the Tarim basin, in the Cenozoic is, to a large extent, well documented by Cenozoic sediments at the northern margin of the West Kunlun. Regional unconformities and sedimentary boundaries record the rhythm of uplifting; sedimentary environment change (coastal marine to lacustrine to fluviatile, alluvial, pluvial fans) notes the variation of the mountain-basin configuration; and thickness and grain size of Cenozoic lithological units may reveal the amplitude and rate of the uplifting.Marine environment (the Tarim Bay) was sustained from the latest Cretaceous to the Oligocene, although it had already retreated to the western part at that time. During this period, gypsum beds, bivalve shell limestone and variegated elastics were formed. 2000 to 3000 m thick Miocene sediments indicate a relatively higher uplifting rate. 2000-3000 m of molasse started in the late Miocene and with a coarsening-up tendency show a rapid and accelerated uplifting from the late Miocene to early Pleistocene. The deposition of molasse was interrupted by a tectonic pulse in the early Pleistocene, which resulted in the high-angle tipping or even being upright and over-turned of the molasse and underlying older sediments. Horizontal middle to late Pleistocene fluvial and pluvial coarse deposits overlying the molasse and older rocks represent the resumption of uplifting, which can also be considered as the continuation of molasse formation. That rivers flowing from the West Kunlun to the Tarim basin cut the middle to late Pleistocene gravel beds and older sediments to a depth of 50 to more than 100 m indicates a high uplifting rate since the Holocene.