Early Paleozoic and Early Mesozoic intraplate tectonic and magmatic events in the Cathaysia Block, South China

Abstract

The geodynamic framework of the South China Craton in the Early Paleozoic and Early Mesozoic has been modeled as developing through either oceanic convergence or intracontinental settings. On the basis of an integrated structural, geochemical, zircon U-Pb and Hf isotopic, and mica 40 Ar/ 39 Ar geochronologic study we establish that an intracontinental setting is currently the best fit for the available data. Our results suggest that widespread tectonomagmatic activity involving granite emplacement and mylonitic deformation occurred during two distinct stages:~435-415 Ma and~230-210 Ma. The coeval nature of emplacement of the plutons and their ductile deformation is corroborated by the subparallel orientation of the mylonitic foliation along the pluton margins, gneissose foliation in the middle part of pluton, the magmatic foliation within the plutons, and the schistosity in the surrounding metamorphosed country rocks. Ar furnace step-heating pseudoplateau ages) along an E-W direction. The geological, geochemical, and isotopic signatures likely reflect far-field effects in response to continental assembly events at these times.

Reconstructing South China in Phanerozoic and Precambrian supercontinents

“…Orogenesis resulted in extensive metamorphism and deformation of pre-Devonian rocks along with granite intrusions and emplacement of minor basalts (Li et al, 2010;Shu et al, 2015;Wang et al, 2012e;Wang et al, 2013c;Wang et al, 2010c;Yao et al, 2012;Zhao et al, 2015). Metamorphism was largely at greenschist facies, but locally reached amphibolite to granulite facies (Yu et al, 2005).…”

“…Post-tectonic Devonian strata unconformably overlie older units and mark a period of post-orogenic transgression that evolved into a Carboniferous to Permian carbonate platform consisting of limestone, dolomite, black chert, and minor sandstones and mudstones, with no coeval magmatism (Shu et al, 2008a;Shu et al, 2015). In the Triassic, the Indosinian Orogeny, manifested by deformation and magmatism at 250-200 Ma, and a regional unconformity between Late Triassic and underlying strata, terminated carbonate sedimentation across the craton (Hu et al, 2015;Shu et al, 2015;Wang et al, 2013a).…”

I-type granitoids associated with the early Paleozoic intracontinental orogenic collapse along pre-existing block boundary in South China

“…Recent studies about sedimentology, biofacies and lithofacies suggest that the tectonic boundary would extend from the Shaoxing-JiangshanPingxiang fault zone to the Hengyang and Longsheng areas (Fig. 1b) (Chen et al, 2012;Shu et al, 2015). Whereas, Wang et al (2003) proposed that the Chenzhou-Linwu Fault could represent the southwestern part of the boundary between the two blocks (Fig.…”

New insights into Phanerozoic tectonics of south China: Part 1, polyphase deformation in the Jiuling and Lianyunshan domains of the central Jiangnan Orogen

“…The early Paleozoic orogeny, termed the Wuyi‐yunkai/Kwangsian orogeny [ Shu et al ., ; Faure et al ., ; Charvet et al ., ; Z. X. Li et al , ; Wang et al ., ], was recognized due to conspicuous development of a regional Middle or Late Devonian unconformity; a hiatus of Silurian sedimentation; early Paleozoic greenschist to amphibolite facies metamorphism, ductile shearing, folding, and crustal melting; and voluminous Silurian magmatism [e.g., Grabau , ; Ting , ; Huang et al ., ; Lin et al ., ; Charvet et al ., ; Shu et al ., , , ; Wang et al ., , ; Charvet , ; Li et al, New insights into Phanerozoic tectonics of South China: Part 2, Early Paleozoic sinistral and Triassic dextral transpression in the north Cathaysia, under review, 2016]. Although intense research has been conducted, many controversies regarding the nature and tectonic environment of the orogeny remain.…”