Abstract:
A large amount of geological information about the evolution, sedimentation and metamorphism of paleo-continental margin is retained in fragment sedimentary rocks from the Kanas Group, which is developed in the Friendship Peak region in the western section of the Altay Mountains, northern Xinjiang.The detrital zircon samples were collected in two rock formations for the study of isotopic dating.The results showed that the distribution characteristics of zircon U-Pb age in the two sets of clastic rocks were similar.The youngest magmatic zircon ages were 546±4 Ma and 545±4 Ma, respectively, which represents the lower limit of the sedimentary age.The relatively older zircon ages can be divided into three categories:3063±16 Ma, 2548±18 Ma and 2541±18 Ma in Archean Eon, 2223~1463 Ma in Paleo-Meso Proterozoic Era, 985~781 Ma in Neoproterozoic Era, which implies that the existence of Precambrian crystalline basement in the sediment source region.The relatively newer zircon age was 421~429 Ma, which is similar to the time of the strong magmatic activities in Altai region..It may be related to the stratum suffering from later hydrothermal deterioration events.The geological structure evolution in northern Xinjiang can be divided into five stages:the formation stage of the Archean continental nucleus, the formation and evolution stage of the Columbia supercontinent, the assembly and breakup stage of the Rodinia supercontinent, the deposition stage of Sinian-Cambrian flysch, the stage of severe magmatic activity in Caledonian.