The Huanan (South China) subcontinent was created by amalgamation of the Yangtze, Xianggan, Ca-thaysia and Zhemin microcontinents by the Guangxi orogeny in the Early Palaeozoic. The closure of the Tethyan Ocean and subsequent collision event outside the amalgamated continent reactivated fossil sutures and resulted in in-tracontinental (ensialic) orogenies in the Mesozoic. Based on evidence from deformation, molasse and granitoids, the Sichuan-Guizhou-Hunan-southern Hubei and Hunan-Jiangxi-Fujian Yanshanian fold-thrust systems and the Lower Yangtze-northwestern Fujian Indosinian fold-thrust system are thought to be intracontinental orogens. Their main features are as follows: intracontinental orogenies occurred areally, thrusting propagated towards the interior of the continental, they extend parallelly to the strikes of the fossil sutures, and the details of the temporal-spatial evolution of the orogens depend on subduction-collision events.
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