How Did South China Connect to and Separate From Gondwana? New Paleomagnetic Constraints From the Middle Devonian Red Beds in South China

摘要

The paleogeographic relationship between South China and Gondwana is critical for understanding the dispersion of Gondwana, accretion of Asia, and evolution of the Paleo-Tethys. However, the lack of robust Devonian paleomagnetic data prevents a confirmative reconstruction of South China's connection to Gondwana and its subsequent separation during the Paleozoic. Here we report a new paleopole (33.6 degrees N, 236.4 degrees E; A(95) = 3 degrees) from the Givetian red beds (similar to 385 Ma) in central South China. Fitting apparent polar wander paths between South China and Gondwana suggests that South China was connected to East Gondwana from the earliest Cambrian to Early Devonian, with its position closed to NW Australia. Thereafter, South China separated from Gondwana during similar to 400-385 Ma, as evidenced by their decoupled apparent polar wander paths. The paleomagnetic data suggest that the Paleo-Tethys Ocean between South China and East Gondwana had been up to similar to 1,600 km latitudinally wide by similar to 360 Ma.