| As one of the youngest orogenic belts,Tibet plateau is still keeping on activities now;and also as the earth's third pole,it effects the survival environment of human,thus,the uplift of Tibet plateau is the focus problem of geoscience at all times,chinese and foreign researchers study Tibet plateau from different sides,have obtained a series of valuable results,and established model and framework of the uplift of Tibet plateau.Evolvement mode includes progressive and phased uplift,those who support later also have different view about when Tibet plateau reached the highest level,14Ma,8Ma,3.4Ma and quaternary are the main points,according to wide planate surfaces,the supporter of progressive uplift believe that Tibet plateau experienced three strong uplift.The west of Tibet plateau is one of strong structure uplift regions,whose uplift process and mechanism play a important role in the research of Tibet plateau,differential uplifting is the main uplift characteristics about the west of Tibet plateau.Based on above ideal,using the method of detrital fission-track,from the angel of coupling basin and mountain,this paper reveals the time of the structure thermal events,uplift process and the rate of cooling denudation about the deposition sources,and set up the uplift framework of the west of Tibet plateau from the angel of low temperature thermal chronology.Zircon and apatite which are the minerals detrital fission track researched on can memorize the time when rocks pass through the closed temperature(110℃,220℃) caused by tectonic uplifting event in source terrains.So statistical peak ages of abundant systematic samples collected from sedimental sections have recorded the time of tectonic-thermal event in the source terrians,further more we can conclude provenance's cooling rate and tectonic uplifting extent.West Kunlun forland basin located in the northwest of Tibet,souththwest of the basin is westkunlun orogenic belt and northeast of the basin is the southwest margin of the Tarim plate. Numbers of previous's studies and analyse through sedimentary profiles indicate that sendimentary source area of West Kunlun forland basin is from south.We have measured the integrated Cenozoic sections Qimugen profile and Yecheng Kekeya profile,and studies of 16 fission track samples concluded as below:during the period 109～165Ma,Bagong Co-Nujiang suture zone developed and experienced subduction,While samples in West Kunlun which is derived from the south of Tibet recorded the tectonic thermal event;During the period 41.9～67.6 Ma,Eurasian plate and India plate collided and spliced,and under the setting of orogenic convergence overall the Tibet,tectonic movement developed and exhumation accelerated.During the period 41.9～67.6 Ma,Indian plate and Tibet plate colliding continuously and subducting severly in the south,while rigid block Tarim plate as a barrier in the north,the lithosphere delaminantion leading West Kunlun terrain shorterning north-south,so this peak age is dominantly in all the detrital fission track samples.During the period 2.6～5 Ma,analysing the xiyu conglomerate and the change of youngest peak age in Atushi formation,WestKun region existed lacal tectonic uplifting response to the rapid and large scale ascending in the whole Tibet.The development and evolution of Zanda basin controlled by"two terrain and three orogenic belt"in Tibet,that is to say Zanda basin lies in the convergence area of north of the Himalaya orogenic belt,southeast of Karakurum orogenic belt and northwest of Yarlung Zangbo Suture Zone,and it is also a Cenozoic basin located between the Gandese terrane and Himalaya terrane.South Tibet detachmemtal is the controlling structure in the southwest of Zanda basin and Ayilariju fault(south east of the Karakurum fault)is the controlling structure in the northeast.In this article I have analysed the source area detailedly and demonstrated that the Cenozoic detrital matters comes from north of the basin.Detrital fission track ages reflect the differential uplifting and tectonic-thermal events'time in Ayiliriju region caused by the activity of Karakorum fault.The evidences of the source analysis showed below:thickness of the sendimentary basin become larger from north to south,which can illuminate that the ancient flow is from north to south,and the source area is Ayilariju region in the north;Based on the occurrences of the gravel's flat surface measured in the field,and do the rose diagram,which also presents that the ancient flow in Zanda basin is fom noth to south opposite to the present flow current;Abundant tabular oblique bedding developled in the sandstone stratum,the occurrences of its foreset bedding 185°∠25°,175°∠35°,205°∠15°,195°∠10°,200°∠30°, the tendency representing the ancient flow direction,from which we can conclude the ancient flow in Zanda basin is fom noth to south.Cenozoic basin analysis of gravel layers,gravel composition is mainly granite and sandstone,while a small number of quartzite and metamorphic rocks and granite in the upper layer increased,gravel composition consistent with exposed stratum in the northern part of the Zanda basin,but can't match the large number of exposed Mesozoic ophiolite,sandstone,shallow Proterozoic metamorphic rocks and metamorphic rocks in the southern part of the basin.As mentioned all the above,the colusinon is that the main source of sediment basin is Ayilariju mountain northern of Zanda basin. Research on Cenozoic detrital fission-track in Zanda basin concluded that:12.6～15.3Ma and 19.88～22.2Ma is the peak of the static with rapid cooling events,reflecting the activity time of the source region's structure fault belt;Detrital fission track peak age of zircon 28.6～33.2Ma, corresponding to the peak age of apatite 27.1～33Ma,which show that there was a thermal event in the source area Ayilariju and Karakorum region;3.6～1.4Ma,from late Pliocene to the Quaternary there is a rapid uplift and exhumation events;Fitting analysis of zircon and apatite FT thermal history,concludes that the cooling rate in source region during 32.6～9.5Ma is 15.4℃/ Ma;During 33.2～14.8Ma,the zircon and apatite rapidly passed through closure temperature and exhumation rate is 1.19mm/a～0.94mm/a;FT thermochronology structure in Zanda basin matching perfectly with thermal event ages in Ayilariju southeastern tip of the Karakoram fault region,from the perspective of thermochronology revealing well the process of basin-mountain coupling,Zanda basin is a Cenozoic basin affected by the activity of Karakorum fault.Comprehensively analyse the research results about clastic fission track geochronology with the two sections,the uplift process of the west Tibet plateau can be divided into some periods, which including the subduction and collision phase in pre-Cenozoic(109～165Ma),the tectonic uplifting phase of syn-collision in paleogene(41～67Ma),the rapid differential uplifting phase in west plateau in early Miocene(19.7～22.2Ma) and the violent uplift and rapid exhumation phase of the west plateau since pliocene(5～1.4Ma).The uplift of the west Tibet plateau has two spatiality rules.First,before Oligocene,in the process of the continent-continent collision and splice,the uplift process and intensity of the west Tibet plateau progressived from south to north. Second,after Oligocene,several orogenic belts were violent uplifting and severely denudating in the same time,so the difference was small.
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