Reappraisal of the ages of Neoproterozoic strata in South China: No connection with the Grenvillian orogeny

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

“…Inset (b) shows the age-spectra of detrital zircons for the Neoproterozoic sedimentary rocks from the Yunkai-Nanling and Jiangnan domains. Data in (b) from Wang et al (2007bWang et al ( , 2008aWang et al ( , 2010a, Zhang et al (2012a), Yu et al (2007Yu et al ( , 2008Yu et al ( , 2010, Wan et al (2007Wan et al ( , 2010, Li et al (2011);Zhao et al (2011) and Zhou et al (2009). An overall northwestward propagation of orogenic assembly of units is supported by the age-spectra of detrital zircons for the Neoproterozoic sedimentary rocks and their derivation from the southeast (inset (b) of Fig. 16, e.g., Wang et al, 2008aWang et al, , 2010aYu et al, 2005Yu et al, , 2010Zhang et al, 2012a).…”

“…These data suggest the backarc basin along the Jiangnan domain developed from ∼850 and its cessation of subduction and final closure at ∼830-820 Ma by the Jinningian Orogen ( Fig. 16; e.g., Zhou et al, 2004;Zhao et al, 2011;Zhang et al, 2011cZhang et al, , 2012cZhang et al, , 2013Zhao and Cawood, 2012 and references therein). In combination with other data, it is inferred that the early Neoproterozoic SCB is characterized by a succession of blocks (e.g., eastern Yangtze, eastern and western Cathaysia) separated by magmatic arcs and back-arc basins (e.g., Wuyi-Yunkai, Shuangxiwu and Jiangnan).…”

“…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. 16, e.g., Wang et al, 2007bZhao et al, 2011;Wang et al, 2012a).…”

“…However, an interior location within Rodinia does not fit readily with the presence of early Neoproterozoic (∼970-900 Ma) rock units of arc or back-arc basin affinities in the easternmost Yangtze Block (e.g., Shui, 1988;Li et al, , 2008aLi et al, 2006Li et al, , 2009Ye et al, 2007;Gao et al, 2009;Chen et al, 2009a,b;Shu et al, 2011;Cawood et al, 2013). Furthermore, additional age-data suggest that final assembly along the Jiangnan domain did not occur until at least ∼830 Ma (e.g., Wang et al, 2006Wang et al, , 2007bWang et al, , 2008bWang et al, ,c, 2011aWu et al, 2006;Zhou et al, 2004Zhou et al, , 2009Zheng et al, 2007Zheng et al, , 2008Zhao et al, 2011;Zhang et al, 2011cZhang et al, , 2012cZhao and Guo, 2012). As a result, the SCB has either been placed on the margin of Rodinia or external to the supercontinent (e.g., Zhao and Cawood, 1999;Torsvik et al, 2001;Yang et al, 2004).…”

“…The crystallization ages of the igneous rocks along the Jiangnan domain are commonly younger than 850 Ma with a cluster of ∼850-820 Ma ( Fig. 16; e.g., Li, 1999;Zhou et al, 2004;Zhong et al, 2005;Wu et al, 2006;Wang et al, 2007bWang et al, , 2008aWang et al, , 2011aZheng et al, 2007Zheng et al, , 2008Zhou et al, 2009;Ma et al, 2009;Xue et al, 2010;Dong et al, 2010;Wang et al, 2010a;Zhao et al, 2011;Zhang et al, 2012cZhang et al, , 2013. These data suggest the backarc basin along the Jiangnan domain developed from ∼850 and its cessation of subduction and final closure at ∼830-820 Ma by the Jinningian Orogen ( Fig.…”