中国科学院南京地质古生物研究所机构知识库

The Neoproterozoic strata exposed in southwestern Hubei Province preserve vital information for understanding the provenance of Cryogenian sedimentary rocks on the Yangtze Block, South China. However, the provenance and depositional age of these strata remain ambiguous. Here, we report new detrital zircon U-Pb ages from the basal and lower Cryogenian Datangpo Formation in southwestern Hubei Province. Two samples yielded four main age clusters at 662-659 Ma, 751-745 Ma, 812-792 Ma and 838-837 Ma, with three minor peaks at 2014 Ma, 2437 Ma and 2602 Ma, indicating that fine-gained siliciclastic deposits of the Datangpo Formation were mainly sourced from Neoproterozoic rocks. The youngest zircon groups for the two samples have average ages of 661.6 +/- 3.8 Ma and 659.0 +/- 2.9 Ma. These data show that the maximum depositional age of the Datangpo Formation on the Yangtze Block is ca. 661 Ma. The results are consistent with published Cryogenian geochro-nological data and demonstrate that the Sturtian deglaciation in South China likely occurred at ca. 661 Ma. Based on the comprehensive analysis of this study and previously published data, we infer that siliciclastics of the Cryogenian Nanhua System in the southwestern Hubei Province were mainly derived from the northern and northwestern margins of the Yangtze Block. The pre-Neoproterozoic zircons were most likely derived from the Yudongzi, Kongling, Douling, Zhongxiang, Huangtuling complexes, whereas the Neoproterozoic zircons were mainly sourced from the Bikou Terrane, Hannan Massif, Wudangshan Group, and Huangling Batholith. Com-parison with detrital zircon age distributions from Australia, India, and Antarctica implies that Nanhua System siliciclastics in the southwestern Hubei Province were sourced internally within the South China Craton. Thus, our results support the hypothesis that the South China Craton was located on the periphery of the Rodinia supercontinent rather than in its interior.