Yangtze and Cathaysia blocks of South China: Their separate positions in Gondwana until early Paleozoic juxtaposition

The position of South China in Gondwana remains controversial. In all previous models, the Yangtze and Cathaysia blocks, the two major components of South China, were amalgamated by the Tonian, and South China was considered to be a single coherent block in Gondwana. Based on a summary and critical reevaluation of available paleomagnetic, paleontological, stratigraphic, and detrital zircon data, we propose that the Yangtze and Cathaysia blocks were not juxtaposed until the early Paleozoic and were located at two separate parts of the northern margin of Gondwana before that time. The Yangtze block was located to the northwest of India in the Ediacaran and early Cambrian. Cathaysia was close to or a part of northern Australia in the Ediacaran, when Australia and India were separated by the Kuunga Ocean, and amalgamated with the eastern margin of India in the late Ediacaran to early Cambrian when the ocean closed. Our model implies that the early Paleozoic orogenesis in South China could have been related to two distinct events, the late Ediacaran to early Cambrian collision of Cathaysia/Australia with India (the Kuunga orogeny) and the Late Ordovician amalgamation of Cathaysia with Yangtze. It also implies that the Yangtze and Cathaysia blocks likely occupied two separate positions in Rodinia.