Correlation between South China and India and development of double rift systems in the South China-India Duo during late Neoproterozoic time
South China, India and their derivative terranes/blocks preserve a larger amount of similar magmatic and sedimentary records related to the tectonic transition from Rodinia to Gondwana. They provide crucial insights into not only the paleogeographic correlation between them but also the geodynamic mechanism for such a transition. Our new detrital zircon U-Pb-Hf data from the Neoproterozoic strata in the Yidun Terrane, show a similar unimodal pattern with a major age population at 0.80-0.76 Ga and similarly positive zircon ƐHf(t) values (+1.1-+10.2) to those in western India and western Yangtze, which sourced from the coeval igneous rocks along the western margin of the Yangtze and India blocks. The Ordovician sequence in the Yidun terrane have consistently multimodal age spectra with three significant components of 0.83-0.76, 1.10-0.90 and 0.60-0.50 Ga with mixing ƐHf(t) values, whose ultimate provenance is the Pan-African Kuunga and Grevillian Eastern Ghats orogens. Thus, the Yidun terrane kept a close linkage with and occupied the western margin of the SCB during the Neoproterozoic-Ordovician. The South China and Indochina blocks were separated from northern Indian after the Middle Cambrian due to the opening of Proto-Tethys Ocean (~500 Ma) and were not welded with Gondwana again.