Detrital zircon U-Pb ages from Early Permian sandstones in Shitoukoumen area,Jilin Province and their geological significance
We present detailed field geological investigations,petrographic observations,and detrital zircon U-Pb data studies of Early Permian sandstones in the Shitoukoumen area,Jilin Province,to discuss their age,provenance and tectonic settings.The Shitoukoumen lithic graywacke is characterized by poor sorting and roundness,as well as complex composition,implying that it is the result of short distance transport and quick accumulation.The U-Pb ages of the 114 obtained detrital zircons range from 480 to 276 Ma,which can be divided into two main age groups:Late Carboniferous-Early Permian(322～276 Ma)and Early Carboniferous(349～323 Ma).There are four other ages of Early Paleozoic and Middle Devonian.By comparing the regional magmatic events,we speculate that the clastic materials of Early Permian sandstones are mainly derived from the Late Carboniferous-Early Permian active continental margin magmatic rocks in the northern margin of the North China Block.Besides,the Early Carboniferous magmatic rocks,the Early Paleozoic magmatic arc,and the Devonian arc-continent collisional magmatic rocks near the study area,together with the Precambrian metamorphic basement of North China Craton,contribute a small number of debris.According to the comprehensive analysis of spectral characteristics of detrital zircon ages,sedimentary features,and tectonic background of the study area,we infer that the Early Permian sandstone should belong to a submarine fan that was formed in an active continental margin setting.As the base materials,the Early Permian standstones in the Shitoukoumen area,together with a series of tectonic rocks and slices with complex components,scales and ages,constitute the ophiolitic mélange during the closure of the Paleo-Asian Ocean.
detrital zirconsandstonePermianactive continental marginShitoukoumen area
万方数据
维普
