Differentiating continental and oceanic arc systems and retro-arc basins in the Jiangnan orogenic belt, South China

Abstract

The Neoproterozoic Jiangnan orogenic belt records the accretion and collision between the Yangtze and Cathaysia blocks in South China. The orogen is divisible into three units: a northeastern domain (also referred to as the Huaiyu or Shuangxiwu domain), a central domain (Jiuling domain) and an undifferentiated southwestern domain. Detrital zircons from the oldest sequences (Shuangqiaoshan, Lengjiaxi, Fanjingshan and Sibao groups) in the central and southwest domains yield similar age spectra with major age populations at c. 875–820 Ma, along with minor Palaeo- to Mesoproterozoic and Archaean ages. The dominance of detrital ages close to the deposition ages of the units, along with juvenile zircon Hf isotopic compositions and arc-like whole-rock compositional data, indicate the sedimentary units accumulated adjacent to a convergent plate margin magmatic arc. The presence of Mesoproterozoic and older zircons, both as detritus in the units and as xenocrysts within igneous rocks displaying a subduction-related signature, along with the compositional data, place the magmatic arc along a continental margin. In the northeastern domain, the oldest coeval sequence (Shuangxiwu and Qigong groups) and arc igneous suites are dated at c. 970–850 Ma, and lack older detritus and xenocrysts, indicating they represent an accreted oceanic arc system.

Geochemistry and geochronology of Upper Triassic sedimentary rocks from the south of the Dabie Orogen: Implications for the paleoenvironment, provenance and tectonic setting

“…Zircon U–Pb dating reveals that the Dabie Orogen displays four primary age groups, with peaks occurring at 2490, 1850, 746 and 412 Ma (Figure 13a; Chen & Xing, 2016; Cheng et al, 2009; Dai et al, 2016; Gao et al, 2002, 2013, 2016; Hacker et al, 1998; He et al, 2011; Huang et al, 2021; Jian et al, 2000; Li et al, 2018; Li, Yu, et al, 2016; Liu, Liu, et al, 2017; Liu et al, 2007; Liu, 2018; Liu et al, 2008, Liu, Gao, et al, 2010，Liu, Jahn, et al, 2010, Liu et al, 2011, Liu et al, 2012; Liu, Yan, & Wang, 2017; Qiu et al, 2020; Sun et al, 2002; Tong et al, 2022; Tuo et al, 2022; Wu & Zheng, 2013; Wu et al, 2008, 2009; Xiang et al, 2012; Xu et al, 2007; Zhang et al, 2020; Zhao et al, 2004, 2007; Zhao et al, 2014, 2016; Zhao, Zhu, Wu, et al, 2021, Zhao, Zhu, Ye, et al, 2021). Within the Jiangnan Orogen, zircon U–Pb dating identifies the primary age group at 846 Ma, accompanied by secondary age groups around 2000 and 2500 Ma (Figure 13b; Chen et al, 2019; Li, Wang, et al, 2016; Meng et al, 2013; Su et al, 2014; Wang et al, 2012; Wang et al, 2014; Yan, Shu, et al, 2015; Yang et al, 2018; Yao, Cawood, et al, 2016; Yao, Shu, et al, 2016, 2019; Ye et al, 2007; Yin et al, 2013; Yu et al, 2020; Zhang et al, 2012; Zhang, Li, & Santosh, 2013; Zhang, Wang, et al, 2013; Zhao & Zhou, …”

Vein Formation and Reopening in a Cooling Yet Intermittently Pressurized Hydrothermal System: The Single-Intrusion Tongchang Porphyry Cu Deposit

“…The eastern SCB comprises the Jiangnan Orogen and Cathaysia block [40] (Figure 1b), separated by the Jiangshan-Shaoxing Fault [37]. The orogen consists of three tectonic domains separated by the Northeast Jiangxi [41] (Figure 1b) and Xiangtan-Miluo faults [42]. The northeast domain is a volcanic arc terrain of arc-derived granite and volcanic rocks (970-880 Ma [43]), with minor turbidite, ophiolitic mélange, and blueschists [44].…”

“…The Cathaysia block comprises the Paleoproterozoic Badu Complex and Wuyishan granites as the basement, overlain by early Neoproterozoic volcanic successions (1000-900 Ma [48,49]. These rock associations have been interpreted as products of slab subduction [34,41,42,47,50,51].…”