Correlation between South China and India and development of double rift systems in the South China–India Duo during late Neoproterozoic time

AbstractSouth China, India, and their derivative blocks preserve many 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 results, combined with published data from these blocks, reveal that South China remained linked with India at least from ca. 830 Ma to ca. 510 Ma and formed the South China–India Duo, which is located at the western margin of Rodinia. The identical magmatism and sedimentation reflect that double late Neoproterozoic rift systems in the South China–India Duo developed owing to the rollback of subducting oceanic slab beneath them. For example, an intracontinental rift developed along the Jiangnan–Aravalli–Delhi fold belt, which separated the Yangtze-Marwar block from the Cathaysia-Bundelkhand block. Another intra-arc rift developed contemporaneously along the northern and western margins of the Yangtze block, through the Marwar terrane of western India, and then into the Seychelles and Madagascar terranes. Such an intra-arc rift is the most feasible explanation for the common development of coeval arclike and extension-related magmatic rocks and extensional sedimentary sequences on the western margin of the South China–India Duo, in Seychelles and Madagascar, and even at other subduction zones. South China was finally separated from Indian Gondwana at ca. 510 Ma due to the opening of the Proto-Tethys Ocean.