Abstract:The Altun mountains along the Northern margin of the Qaidam basin is a collisional orogenic belt strongly modified by strike-slip-faults, constituing the current nothern tectonic boundary of Qinghai-Tibet Plateau. Its uplift is remarkable part of the cenozoic uplift of Qinghai-Tibet Plateau. In this contribution, we present LA-ICPMS U-Pb dating results of detrital zircons, together with heavy mineral assemblages from sandstones of the Xiaganchaigou formation (E31) and lower segment of the Xiayoushashan formation (N21) from northwest Qaidam Basin. Our results show that there are significant Indosinian and Caledonian age populations in all samples. However, significant differences in age spectrums exist between the samples from Xiaganchaigou formation ages and those from Xiayoushashan formation. Indosinian peaks in the ages spectrums of Xiaganchaigou samples are stronger than those of Xiaganchaigou, whereas the of Caledonian peak gradually become stronger in Xiayoushashan samples. The stability of Heavy mineral assemblages decrease severely from the Xiaganchaigou formation to the Xiayoushashan formation , indicating that their debris changed from a high maturity into a low maturity level, reflecting that provenance area for the Xiaganchaigou formation is much farther than the Xiayoushashan formation. All these results imply that Altun experienced a significant uplift in the the early Oligocene and early Pliocene. Although the subduction-collision orogeneiss of Altun belt orogenic belt was completed in the early Paleozoic., the currently exposed Altun mountains was primarily formed by much later tectonic movement, i.e. uplifting asociated with strike-slip faulting in Cenozoic. This work also confirmed the U-Pb age spectrum of detrital zircon, associated with heavy mineral assemblage analysis is an effective tool in research of strat provenance and basin-mountain coupling.