Detrital zircons reveal no Jurassic plateau in the eastern North China Craton

U-Pb-Hf isotopic analyses have been carried out on detrital zircons from Late Permian-Jurassic strata in the Western Shandong-Bohai Bay (WSBB) basins with aims of constraining the paleogeography and evolution of the eastern North China Craton (NCC). Four major groups of U-Pb ages (namely, 3.0-2.3 Ga, 2.2-1.4 Ga, 1250-430 Ma and 410-150 Ma) are recognized for zircons from the fine-grained sandstones. The post-Paleoproterozoic zircons of the Late Permian sample show an age cluster of 344-255 Ma with epsilon(Hf)(t) values of -18 to -8, being similar to those extracted from Late Paleozoic igneous rocks from the Yinshan-Yanshan Orogenic Belt (YYOB) on the northern margin of the NCC. However, the Devonian-Jurassic zircons (390-150 Ma) from the Jurassic sediments have epsilon(Hf)(t) values from -45 to +14, very similar to the mixture of Phanerozoic zircons from the Xing-Meng Orogenic Belt (XMOB) and the YYOB, but significantly different from those of the Liaodong Peninsula, Jiaodong Peninsula and the Western Shandong Uplift. In addition, Cambrian-Silurian zircons (535-430 Ma) of the Jurassic samples have epsilon(Hf)(t) values from -27 to +7, resembling the Early Paleozoic zircons extracted from the Northern Qinling Orogen (NQO). The U-Pb age spectra and Hf isotope of Devonian-Jurassic zircons as well as bulk Nd isotopes suggest that the central eastern NCC received some juvenile materials from the XMOB, the YYOB and the NQO during the Jurassic. This indicates widespread prototype basins and a low elevation during the Jurassic, arguing against the presence of a paleo-plateau in the eastern NCC at that time. The lack of evidence predicted by lithospheric delamination (e.g., large-scale elevation or doming after Late Triassic) makes the delamination unlikely to be a viable mechanism of lithospheric thinning of the NCC The subsidence rather than elevation of the eastern NCC after Late Triassic might be related to thermo-chemical erosion of the lithosphere by underlying convective mantle in a back-arc setting. (C) 2012 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.