The Neoproterozoic-Early Paleozoic tectonic evolution of the South China Block: An overview

Jacques Charvet (1)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327

This paper gives a brief review of what I consider as the state of the art regarding the largely accepted data and ideas concerning the Proterozoic to Early Paleozoic tectonic evolution of South China. The South China craton was built by the welding of the Yangtze and Cathaysia blocks, with a different previous history giving a different pre-Neoproterozoic basement composition, due to the Jiangnan (Jinning, Sibao) orogeny. This Jiangnan orogeny was a collisional event, induced by the consumption of an intervening oceanic domain by subduction beneath the Yangzte plate. The evolution involved a volcanic arc on the Yangtze active margin, active from ca. 980 Ma to ca. 850 Ma, the subsequent collision beginning at around 870-860 Ma and responsible for the emplacement of thrust sheets of ophiolitic mélange (dated around 1000-900 Ma) and blueschists (900-870 Ma), followed by late- to post-collisional granitic plutonism (840-800 Ma). The newly amalgamated South China craton suffered from rifting, starting around 850 Ma, marked by mafic-ultramafic magmatism until ca. 750 Ma. The Nanhua rift basin evolved with a thick sedimentation in its middle part until the Ordovician. South China was affected by the early Paleozoic orogeny (mainly Silurian), characterized by a strong quasi-symmetrical intracontinental shortening, involving the sedimentary cover of the rift and its margins as well as the basement, leading to crustal thickening. This crustal thickening induced an important anatexis and emplacement of peraluminous granites during the Silurian. Unlike the Jiangnan orogeny, which was of collisional type, the Early Paleozoic one was a bit similar to a Pyrenean intracontinental type. Some pending problems need further research for clarification, for example: the location and timing of integration of South China within Rodinia, the triggering factor of the Early Paleozoic orogeny, the mapping of the contacts bounding the Lower Paleozoic thrust sheets responsible for the crustal thickening.

Mots clés: South China; Yangtze block; Cathaysia block; Jiangnan orogeny; Early Paleozoic orogeny; Tectonic evolution

Domaines: Tectonique; Milieux et Changements globaux

Jacques Charvet. The Neoproterozoic-Early Paleozoic tectonic evolution of the South China Block: An overview. Journal of Southeast Asian earth sciences, 2013, 74, pp.198-209. ⟨10.1016/j.jseaes.2013.02.015⟩. ⟨insu-00796995⟩