Source-to-sink of Late carboniferous Ordos Basin: Constraints on crustal accretion margins converting to orogenic belts bounding the North China Block

作者：Anqing Chen,Hao Zou,James G.Ogg,Shuai Yang,Mingcai Hou,Xiuwei Jiang,Shenglin Xu,Xiaoxing Zhang

摘要：The Upper Carboniferous Benxi Formation of the Ordos Basin is the lowest strata overlying Middle Ordovician above the major ca.150-Myr sedimentary gap that characterizes the entire North China Block(NCB).We apply an integrated analysis of stratigraphy,petrography,and U-Pb dates and Hf isotopes on detrital zircons to investigate its provenance and relationships to the progressive collisions that formed the Xing’an-Mongolia Orogenic Belt to the north and the Qinling Orogenic Belt to the south.The results show that,in addition to regional patterns of siliciclastic influx from these new uplifted sources,the Benxi Formation is composed of two sequences corresponding to long-term glacial-interglacial cycles during the Moscovian to lower Gzhelian stages which drove global changes of eustatic sea level and weathering.The spatio-temporal distribution of sediment isopachs and facies indicate there were two sediment-infilling pulses,during which the southern and the northern Ordos Basin developed tidal-reworked deltas.The age spectra from detrital zircons,trace element patterns and εNd(t)values reveal that the siliciclastics forming the southern delta was sourced in the Qinling Orogenic Belt,whereas the northern delta was derived from the Xing’an-Mongolia Orogenic Belt.The source-to-sink evolution of this Upper Paleozoic system records the progressive development of orogenic belts and uplifts forming on the southern and northern margins of the NCB prior to its collisions with the South China and the Siberian plates,respectively.

發文機構：State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Department of Earth Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation of Ministry of Land and Resources State Key Laboratory of Lithospheric Evolution

關鍵詞：BenxiformationDetritalzirconsCentralasianorogenbeltTECTONICSPALEOGEOGRAPHYMoscovianandkasimovian

分類號： P53[天文地球—古生物學與地層學]