Neoproterozoic active continental margin in the southeastern Yangtze Block of South China: Evidence from the ca. 830–810Ma sedimentary strata

Reconstructing South China in Phanerozoic and Precambrian supercontinents

“…830-810 Ma (Li et al, 2013c;Wang et al, 2016b;Zhang et al, 2012b;Zhao, 2015). This age relationship indicates that accretion of these blocks was not complete until this time and is consistent with an external location for South China, either within an already assembled Rodinia or as part of independent plate separated from Rodinia.…”

“…Rhyolite dated at 972 Ma from the southeast margin of western Cathaysia is also characterized by depletion of Nb and Ta and an inferred magmatic arc origin (Shu et al, 2008b). The composition and provenance record of the sedimentary rocks is also consistent with derivation from a magmatic arc source (Wang et al, 2016b). Supra-subduction zone ophiolite rocks, which overlap with the overall duration of arc magmatism have also been recognized in the eastern Jiangnan Orogen Yao et al, 2016a;Zhang et al, 2013a;Zhang et al, 2015a).…”

“…The internal model requires subduction to be completed by 890 Ma (Li et al, 2002b;Li et al, 2008c) or 860 Ma (Shu and Charvet, 1996) and subsequent magmatism is related to lithospheric extension associated with a mantle plume, whereas the external model has subduction continuing until as late as 830-810 Ma (Wang et al, 2016b) between Yangtze and Cathaysia and 730-700 Ma on the western margin of Yangtze (Dong et al, 2012a;Zhou et al, 2002). Similarly, movement of South China from an internal location within Rodinia to an external location in Gondwana implies a different provenance record than a peripheral Rodinian model in which the position of South China with respect to India is essentially fixed through the Neoproterozoic, which is also similar to the model in which South China and India are independent of Rodinia.…”

Provenance, depositional setting, and crustal evolution of the Cathaysia Block, South China: Insights from detrital zircon U–Pb geochronology and geochemistry of clastic rocks

“…Our age data from detrital zircons also show another cluster of middle Neoproterozoic ages (850–730 Ma), which is considered to be associated with the breakup of the Rodinia supercontinent (e.g., Z. X. Li et al, ; Shu et al, ; Zhao et al, ). It is widely considered that the Cathaysia and Yangtze blocks amalgamated to form the unified SCB during the Neoproterozoic, while the nature and timing of this amalgamation are still controversial (e.g., Z. X. Li et al, ; X. H. Li et al, ; X. L. Wang et al, ; W. Wang et al, ; Xia et al, ; Yu et al, ; Zhao & Cawood, ; Zhao, ; Zhou, Yan, et al, ; Zhou et al, ). Through comparing the intrusive dykes between South China and Australia, Z. X. Li et al () and X. H. Li et al () concluded that the collision between these two blocks happened at 1,000–880 Ma and the subsequently upwelling of mantle plume around 830 Ma resulted in the breakup of South China.…”

“…The assembly of the Gondwana supercontinent was beginning after the breakup of Rodinia in the Neoproterozoic and was completed in the early Palaeozoic (Boger, Carson, Wilson, & Fanning, ; Cawood et al, ; Duan, Meng, Zhang, & Liu, ; Y. J. Xu, Cawood, Du, Zhong, & Hughes, ). However, the position of the SCB and its tectonic affinity with some other continental blocks within the supercontinents continue to be controversial (e.g., Cawood et al, ; Cawood et al, ; W. Wang et al, ; W. H. Yao, Li, et al, ; Yu et al, ; Zhou, Kennedy, et al, ). Within the SCB, although many investigations have been under taken to understand its tectonic evolution during Palaeoproterozoic to Palaeozoic in the past two decades (e.g., X. H. Li et al, ; Shu et al, ; Y. J. Wang et al, ; Xia et al, ; Xia, Xu, & Zhu, ; X. S. Xu et al, ; X. S. Xu, O'Reilly, Griffin, Deng, & Pearson, ; W. H. Yao, Li, et al, ; J. L. Yao, Shu, et al, ; Ye, Li, Li, Liu, & Li, ; Zhao, ), the detailed processes and final time related to the amalgamation between the Cathaysia and Yangtze blocks, whether there is a Huanan Ocean exists between the Cathaysia and Yangtze blocks and the nature of the later Wuyi–Yunkai orogeny in the Palaeozoic, have long been a matter of debate.…”