Seminar

The South China Craton has been variously linked with the Precambrian supercontinents of Columbia/Nuna, Rodinia and Gondwana. It is divisible into three Precambrian tectonic units, the Yangtze and Cathaysia blocks and the intervening Neoproterozoic Jiangnan Orogen (also referred to as the Jinning or Sibao Orogen). The Jiangnan Orogen includes a number of convergent plate margin successions that resulted in assembly of the Cathaysia and Yangtze blocks. Shortly after assembly, the Jiangnan Orogen and Cathaysia Block underwent regional extension, resulting in development of the Nanhua rift basin. The overall tectonic evolution of the Jiangnan Orogen, including timing and nature of arc-trench successions and related subduction polarity, age of final assembly, geodynamics of S-type granites, and the role of the orogen within the supercontinent cycles, are disputed. Two end-member tectonic models have been proposed for South China involving ‘plume rifting’ and ‘subduction-collision’ settings and reflect uncertainty in age and affinities of the rock units within the orogen. However, available data and observations, especially those published in recent years, including timing of regional unconformity and deformation, overlapping of ages of S-type granites with convergent margin successions, disagree with age and relationships outlined in previous models.

Our works document the tectonostratigraphic evolution of the Jiangnan Orogen, including litho-stratigraphic sequences, magmatic suites, metamorphic and structural events, and the geochemical and isotopic character of units, concentrating on data patterns across the belt. From these results, we address the inconsistency of previous models and provide constraints on the overall geodynamic evolution of the orogen, as well as Paleogeography of South China Craton with respect to the Rodinia supercontinent.