Résumé
Foreland of large mountains ranges with their fold-and-thrust belt and flexural basin provide long and detailed records of the history of mountain growth. The Junggar basin, north of the Tian Shan, Western China, is a unique case of examples where the development of folding and rate of sedimentation in the flexural basin can be unravelled from the sedimentary record. The Tianshan is a 2500 km long Est-west mountain belt that dominated the central Asia topography with summit higher than 7000 m. The range was originally built during Devonian to Carboniferous, then reactivated during Cenozoic by the India-Asia collision. On both its northern and southern sides the Tianshan present piedmonts composed by series of fold and thrust belts with excellent surface exposures. Deep structures are constrained by seismic lines run for gas and oil exploration. We combine structural model of the piedmont and foreland basin, with chronological constraints on the stratigraphy derived from magnetostratigraphic sections to determine recent deformation and erosion rates.