Provenance and tectonic setting of Neoproterozoic sedimentary sequences in the South China Block: evidence from detrital zircon ages and Hf–Nd isotopes

Abstract

Neoproterozoic sedimentary sequences in the South China Block provide great opportunity to examine the tectonic evolution and crustal accretion during this period. This study presents U-Pb ages and Hf isotope composition of detrital zircons and Nd isotope composition of whole rocks of the Neoproterozoic sequences from the Yangtze Block, part of the South China Block. Age patterns of detrital zircons imply that the source area experienced three major periods of magmatic activity at 2,300-2,560, 1,900-2,100 and 770-1,000 Ma and two major episodes of juvenile crust accretion at 2,600-3,400 and 770-1,000 Ma. The maximum age of the Gucheng glaciation can be restricted at *768 Ma from the youngest detrital zircon ages, probably corresponding to the Kaigas glaciation rather than to the Sturtian glaciation. High La/Sc ratio and low Cr/Th, Sc/Th and Co/Th ratios of the sedimentary rocks point to a derivation from dominantly felsic upper continental crustal sources, whereas large variation of e Nd (t) and e Hf (t) values indicates that mantle-derived magmatic rocks also provided material to the sedimentary sequences in different degrees. The shift in e Nd (t) values of whole rocks and U-Pb age spectra of detrital zircons records the evolution from a back-arc to retro-arc foreland to a rift basin. Age distribution of detrital zircons from the Neoproterozoic sequences, compared with those of the major crustal blocks of Rodinia, implies that the position of the Yangtze Block was probably adjacent to northern India rather than between Australia and Laurentia before the breakup of the Rodinia supercontinent.

Late Permian to Early Triassic crustal evolution of the Kontum massif, central Vietnam: zircon U–Pb ages and geochemical and Nd–Hf isotopic composition of the Hai Van granitoid complex

“…Chen and Jahn 1998;Wang et al 2010Wang et al , 2012. Besides, our data attest to the presence of Neoproterozoic (i.e.…”

Geochronological and geochemical evidence for the nature of the Dongling Complex in South China

“…and the Chengjiang Formation. There is an increasing amount of detrital zircon U-Pb age data for these strata recently (Yin et al, 2003;Zhang et al, 2006c;Liu et al, 2008;Wang et al, 2012aWang et al, ,d, 2013cDu et al, 2013). In contrast, there is a limited amount of detrital zircon U-Pb age data for Neoproterozoic strata in the Cathaysia terrane (Wan et al, 2007;Yu et al, 2008Yu et al, , 2010, which is commonly ascribed to intensive reworking of the Precambrian rocks during the Phanerozoic .…”

“…The bolstering evidence includes the development of bimodal volcanism since ∼780 Ma Yin et al (2003), Zhang et al (2006c), Wan et al (2007), Liu et al (2008), Yu et al (2008Yu et al ( , 2010, Wang et al (2012aWang et al ( ,d, 2013c and Du et al (2013). Only U-Pb ages with discordance less than ±5% are accepted for plotting.…”

“…Despite the limited outcrops of ∼2.0 Ga rocks, many studies have reported U-Pb ages of ∼2.0 Ga for relict zircons from volcanic and intrusive rocks (Zheng et al, 2006;Zhang et al, 2009) and detrital zircons in different strata Zhang et al, 2006c;Wang et al, 2010aWang et al, , 2012aWang et al, ,b,c, 2013c throughout the Yangtze craton and its adjacent Jiangnan orogen. In particular, detrital zircons from the strata of the Cryogenian system (the Nanhua system), in both the northern part and the southeastern margin of the Yangtze craton, show a prominent age peak at ∼2.0 Ga (e.g., Liu et al, 2008;Wang et al, 2012b).…”

On the geochemistry of the Late Quaternary loess deposits of Dobrogea (Romania)

“…(For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Nesbitt and Young, 1996;Újv ari et al 2008Wang et al, 2012;Xie et al, 2014).…”