The Altyn Tagh fault (ATF) is the longest (>2000 km-long) left-lateral strike-slip fault in Asia.It played an important role during the India-Eurasia collision.Many studies have focused on the accessible eastern and central segments of the ATF,whereas its western segment, more remote and at very high elevation,remains poorly constrained.The Ashikule fault lies where the ATF changes direction,near the western end of the ATF,and becomes the Karakax fault,where a series of strands splay off the main fault.Slip-rates along the Ashikule fault remained unknown until today.Based on the interpretation of satellite images,field investigation,total station surveying,and cosmogenic nuclide 10Be dating,we provide the first quantitative late Pleistocene slip-rates along the Ashikule segment of the ATF,as well as uplift rates for the northwestern Qinghai-Tibetan Plateau.At least 7 terraces developed along the Akesu River,east of the Ashikule basin,and all have been offset by the Ashikule fault,where the recent 2008 Ms7.2 Yutian earthquake.Horizontal displacements of different terraces were measured by retro-deformation on satellite images and total station surveying,and are ~11 m,~33 m,~105 m,~220 m,and ~660 m,for the T2/T0 riser,T3/T2 riser,T4/T3 riser,T5/T4 riser,and T6/T5 riser,respectively.Combining the offsets with cosmogenic ages (7.7±0.7 ka,32.7±3.1 ka,53.6±2.5 ka,115.7±23.2 ka,166.8±10.4 ka,and 195.1±8.5 ka,for T1 to T6,respectively),slip-rates along the Ashikule fault seem to range from 0.3 to ~1.9 mm/yr,possibly up to ~4 mm/yr.These rates are lower than those along other segments of the ATF.We consider that because the Ashikule fault is located in the local transtension environment where the ATF changes direction and becomes the Karakax fault, normal faulting here absorbs part of the horizontal slip,therefore producing a slower horizontal slip-rate.The 7 terraces of the Akesu River attest to the tectonic uplift in this region.Combining the cosmogenic ages on the different terraces with their height above the modern river (measured in the field with total station),incision rates of 0.2-0.35 mm/yr can be constrained for the Akesu River.This may translate to the late Pleistocene uplift rate of the northwestern Qinghai-Tibetan Plateau.