Tectonic setting of the South China Block in the early Paleozoic: Resolving intracontinental and ocean closure models from detrital zircon U-Pb geochronology

Abstract

Zircon U‐Pb geochronological data on over 900 zircon grains for Cambrian to Silurian sandstone samples from the South China Block constrain the pre‐Devonian tectonic setting of, and the interrelationships between, the constituent Cathaysia and Yangtze blocks. Zircons range in age from 3335 to 465 Ma. Analyses from the Cathaysia sandstone samples yield major age clusters at ∼2560, ∼1850, ∼1000, and 890–760 Ma. Zircons from the eastern and central Yangtze sandstone samples show a similar age distribution with clusters at ∼2550, ∼1860, ∼1100, and ∼860–780 Ma. A minor peak at around 1450 Ma is also observed in the Cathaysia and central Yangtze age spectra, and a peak at ∼490 Ma represents magmatic zircons from Middle Ordovician sandstone in the eastern Yangtze and Cathaysia blocks. The Cambrian and Ordovician strata show a transition from a carbonate‐dominated succession in the central Yangtze Block, to an interstratified carbonate‐siliciclastic succession in the eastern Yangtze Block, to a neritic siliciclastic succession in the Cathaysia Block. Paleocurrent data across this succession consistently indicate directions toward the W‐NNW, from the Cathaysia Block to the Yangtze Block. Our data, together with other geological constraints, suggest that the Cathaysia Block constitutes a fragment on the northern margin of east Gondwana and both Cathaysia and east Gondwana constituted the source for the analyzed early Paleozoic samples. The similar age spectra for the Cambrian to Silurian sandstone samples from the Yangtze and Cathaysia blocks argue against the independent development and spatial separation of these blocks in the early Paleozoic but rather suggest that the sandstone units accumulated in an intracontinental basin that spanned both blocks. Subsequent basin inversion and Kwangsian orogenesis possibly at 400–430 Ma also occurred in an intracontinental setting probably in response to the interaction of the South China Block with the Australian‐Indian margin of east Gondwana.

Geochronological, geochemical and Nd–Hf–Os isotopic fingerprinting of an early Neoproterozoic arc–back-arc system in South China and its accretionary assembly along the margin of Rodinia

“…The final amalgamation along the Wuyi-Yunkai domain is roughly synchronous with the deformation of the East Ghats of India (∼960 Ma) and the northern Prince Charles Mountains of East Antarctica (∼990-960 Ma; e.g., Boger et al, 2000;Jayananda et al, 2000). These relationships, combined with the biogeographic consistency of the eastern SCB with Australia and the late Neoproterozoic tectonic relationship with India (e.g., Wang and Li, 2003;Yang et al, 2004;Myrow et al, 2006Myrow et al, , 2009Wang et al, 2010b), suggest to us that the SCB was situated along the margin of Rodinia between Australia and East Antarctica (e.g., Hoffman, 1991;Yang et al, 2004), as shown in Fig. 17.…”

“…Li et al, 2010c;Wang et al, 2012b,c). Recent geochronological data have shown that the Neoproterozoic and even Paleozoic units are additionally presented within the previously mapped basement succession (e.g., Li et al, 1998;Wang et al, 2007cWang et al, , 2010bWang et al, , 2011bWang et al, , 2012cWan et al, 2007Wan et al, , 2010Yu et al, 2009Yu et al, , 2010Li et al, 2010aLi et al, ,c, 2011. Within the Cathaysia basement, there are small amounts of mafic and ultramafic rocks (e.g., amphibolite, metagabbro, metadiabase, metabasite, peridotite and pyroxenite), which occur mainly as lens, pods and fragments (e.g., Fujian BGMR, 1985;Guangxi BGMR, 1985;Guangdong BGMR, 1988;Zhejiang BGMR, 1989;Zhang et al, 2012a).…”

“…16, e.g., Wang et al, 2008aWang et al, , 2010aYu et al, 2005Yu et al, , 2010Zhang et al, 2012a). The Neoproterozoic successions along the Wuyi-Yunkai domain by equigranular and rounded or subhedral, indicating detritus transported from the orogen to south or southeast (e.g., Wan et al, 2007Wan et al, , 2010Yu et al, 2007Yu et al, , 2008Yu et al, , 2010Wang et al, 2008aWang et al, , 2010bLi et al, 2011). Further to the west, along the Jiangnan domain, ∼1.0 Ga detrital zircons are poorly identified and the age-spectra are characterized by ∼0.86 Ga grains (inset (b) of Fig.…”

Zircon U–Pb, molybdenite Re–Os and muscovite Ar–Ar isotopic dating of the Xitian W–Sn polymetallic deposit, eastern Hunan Province, South China and its geological significance

“…Widespread, intense Yanshanian granitic magmatism and mineralization in South China have attracted attention of geologists (Jahn et al, 1976;Charvet et al, 1994;Lan et al, 1996;Sewell and Campbell, 1997;Wang et al, 2010bWang et al, , 2011aWang et al, , 2011b. However, the tectonic regime responsible for the Yanshanian magmatism and related W-Sn mineralization is still debated.…”

Detrital zircon U–Pb ages of the Proterozoic metaclastic-sedimentary rocks in Hainan Province of South China: New constraints on the depositional time, source area, and tectonic setting of the Shilu Fe–Co–Cu ore district

“…Detrital zircons with the age cluster of 1700-1200 Ma are widely reported for (meta)sedimentary rocks in both the Yangtze and the Cathaysia Blocks of South China ( Fig. 9b and c; Li et al, 2007;Greentree et al, 2006;Wang et al, 2007aWang et al, , 2010bWang et al, , 2012aWang et al, , 2013bWang et al, , 2014aYu et al, 2008Yu et al, , 2010Sun et al, 2009;Zhou et al, 2009;Wan et al, 2010;Wu et al, 2010;Duan et al, 2011;Yao et al, 2011Yao et al, , 2012Xu et al, 2012;Cawood et al, 2013b). However, rocks with this age range rarely occurred in the South China, except for the metamorphosed volcanic rocks with ages of ca.…”