Geochronological And Sedimentological Evidence Of Panyangsha Foreland Basin For Tectonic Control On Late Paleozoic Plate Marginal Orogenic Belt In The Northern Margin Of The North China Craton

There is a wide support that theInner Mongolia Palaeo-upift on the northern margin of the North China Craton has undergone an uplifting history.However,when and how did the uplift occurred keeps controversial.Extensive field-based structural,metamorphic,geochemical,geochronological and geophysical investigations on the Inner Mongolia Palaeo-upift,which suggested that the Inner Mongolia Palaeo-upift was an uplifted region since the Early Precambrian,or range from Late Carboniferous-Early Jurassic.The geochemical characteristics of the Late Paleozoic to Early Mesozoic intrusive rocks indicated that the Inner Mongolia Palaeo-upift was an Andean-type continental margin related to the closure of the Paleo-Asian Ocean or the extensional tectonic setting after the closure of the Paleo-Asian Ocean led to the upwelling of asthenosphere material.To address the spatial and temporal development of the Inner Mongolia Palaeo-upift,we have carried out provenance analysis of Permian sedimentary rocks collected from the Panyangshan basin along the northern margin of the North China Craton.The QFL diagram revealed a dissected arc-recycled orogenic tectonic setting.Moreover,the framework grains are abundant with feldspar(36%-50%),indicating that short transport distance and unstable tectonic setting.Detrital zircon U-Pb analysis ascertained possible provenance information: the Precambrian basement(~2490 Ma and ~1840 Ma)and continental arc magmatic action(~279 Ma and ~295 Ma)along the northern margin of the North China Craton.Moreover,the projection in rose diagrams of the mean palaeocurrent direction,revealing the NNWSSE(305°~125°,356°~176°),NNE-SSW(4°~184°),SSW(202°,244°,190°),SSE(170°,179°,176°)palaeoflow direction,also shows that the provenance of the Panyangshan basin sources mainly from the Inner Mongolia Palaeo-upift.The andesite overlying the Naobaogou Formation,has yielded U-Pb age of 277.3±1.4 Ma.The dioritic porphyry dike intruded the Naobaogou and Laowopu Formations,which has an emplacement age of 236±1 Ma.The above data identify that the basin formed range from Early Permian to Middle Triassic(277–236 Ma).Accordingly,the Inner Mongolia Palaeo-upift also was developed in the Early Permian to Middle Triassic(277–236 Ma),related to the final closure of the Paleo-Asian Ocean and the collision between the North China Craton and the Siberian Craton.The results of our study advocate the tectonic setting of Inner Mongolia Palaeo-upift which was probably belong to the Platemarginalorogenicbelt in the period between 277–236 Ma(Early Permian-Middle Triassic).