Late Cenozoic differential uplift-exhumation of batholith and propagation of uplift recorded by fission track thermochronology in Chayu area,the southeast margin of the Tibetan plateau.

Study on Late Cenozoic propagation of uplift in the southeast margin of the Tibetan Plateau is critical to link with development of intra-continental deformation in the periphery of the Tibetan Plateau.The apatite fission track analysis in Chayu area of the southeast Tibetan Plateau reveals that the Late Cenozoic differential uplift-exhumation of Demula,Arza Gongla and Chayu batholiths,which arrayed from north to south and controlled by faults,is a proxy of propagation of uplift.The time series of uplift- exhumation are ca.15.1～13.7Ma,6.3～4.3Ma,3.5～3.3Ma,1.9～1.7Ma and 1.1～1.0Ma and the overall activities show southward propagation and migration.It is in Late Miocene (ca.6～5Ma) that uplift-exhumation rate turns speedup with a regional response in southeast Tibet and northwest Yunnan and may establish the development pattern of modern terrain for the southeast margin of the Tibetan Plateau.From the southeast to northeast of the Tibetan Plateau,the outward propagation and growth of late Cenozoic deformation is characterized by multistage,coeval and disequilibrium developments.