new u pb age constraints on the upper banxi group and synchrony of the sturtian glaciation in south china

Accepted Manuscript New U-Pb age constraints on the upper Banxi Group and synchrony of the Sturtian glaciation in South China Gaoyuan Song, Xinqiang Wang, Xiaoying Shi, Ganqing Jiang PII: S1674-9871(16)30210-9 DOI: 10.1016/j.gsf.2016.11.012 Reference: GSF 517 To appear in: Geoscience Frontiers Received Date: October 2016 Revised Date: 24 October 2016 Accepted Date: 24 November 2016 Please cite this article as: Song, G., Wang, X., Shi, X., Jiang, G., New U-Pb age constraints on the upper Banxi Group and synchrony of the Sturtian glaciation in South China, Geoscience Frontiers (2017), doi: 10.1016/j.gsf.2016.11.012 This is a PDF file of an unedited manuscript that has been accepted for publication As a service to our customers we are providing this early version of the manuscript The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain AC C EP TE D M AN U SC RI PT ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT New U-Pb age constraints on the upper Banxi Group and synchrony of the Sturtian glaciation in South China RI PT Gaoyuan Songa, Xinqiang Wanga,b,*, Xiaoying Shia,b, Ganqing Jiangc a School of Earth Science and Resources, China University of Geosciences (Beijing), Beijing 100083, China b State Key Laboratory of Biogeology and Environmental Geology, Beijing 100083, China Corresponding author wxqiang307@126.com address: wxqiang@cugb.edu.cn, TE D Abstract e-mail SC Department of Geoscience, University of Nevada, Las Vegas, NV 89154-4010, USA M AN U c The Nanhua basin in South China hosts well-preserved middle–late Neoproterozoic sedimentary and volcanic rocks that are critical for studying the basin evolution, the EP breakup of the supercontinent Rodinia, the nature and dynamics of the "snowball" AC C Earth and diversification of metazoans Establishing a stratigraphic framework is crucial for better understanding the interactions between tectonic, paleoclimatic and biotic events recorded in the Nanhua basin, but existing stratigraphic correlations remain debated, particularly for pre-Ediacaran strata Here we report new Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) U-Pb zircon ages from the middle and topmost Wuqiangxi Formation (the upper stratigraphic unit of the Banxi Group) in Siduping, Hunan Province, South China Two samples show ACCEPTED MANUSCRIPT similar age distribution, with two major peaks at ca 820 Ma and 780 Ma and one minor peak at ca 910 Ma, suggesting that the Wuqiangxi sandstone was mainly sourced from Neoproterozoic rocks Two major age peaks correspond to two phases RI PT of magmatic events associated with the rifting of the Nanhua basin, and the minor peak at ca 910 Ma may correspond to the Shuangxiwu volcanic arc magmatism, which represents pre-collision/amalgamation subduction on the southeastern margin SC of the Yangtze Block The youngest zircon group from the topmost Wuqiangxi M AN U Formation has a weighted mean age of 714.6 ± 5.2 Ma, which is likely close to the depositional age of the uppermost Banxi Group This age, along with the ages reported from other sections, constrains that the Banxi Group was deposited between ca 820 Ma and ca 715 Ma The age of 714.6 ± 5.2 Ma from the top of the Wuqiangxi TE D Formation is indistinguishable with the SIMS U-Pb age of 715.9 ± 2.8 Ma from the upper Gongdong Formation in the Sibao village section of northern Guangxi, South China It is also, within uncertainties, overlapped with two TIMS U-Pb ages from EP pre-Sturtian strata in Oman and Canada These ages indicate that the Jiangkou AC C (Sturtian) glaciation in South China started at ca 715 Ma instead of ca 780 Ma and support a globally synchronous initiation of the Sturtian glaciation at ca 715 Ma Keywords Nanhua basin; Wuqiangxi Formation; Banxi Group; U-Pb zircon ages; Sturtian glaciation; South China C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT Introduction The middle–late Neoproterozoic sedimentary and volcanic strata (ca 820–541 Ma) are well preserved in the Nanhua basin, South China (Wang and Li, 2003; Li et al., RI PT 2008a,b; Jiang et al., 2011; Zhao et al., 2011) These records are crucial for understanding the evolution of the Neoproterozoic Nanhua basin (e.g., Wang and Li, 2003; Li et al., 2008b, 2009; Zhao et al., 2011; Wang et al., 2012b, 2015; Zhang et al., SC 2013, 2015a,b) and provide a unique archive to study the breakup of the M AN U supercontinent Rodinia (e.g., Li et al, 1999, 2008b, 2013; Cawood et al., 2013), the nature and dynamics of Neoproterozoic "snowball" Earth (Evans et al., 2000; Jiang et al., 2003a; Zhou et al., 2004; Bao et al., 2008; Zhang et al, 2008c; Huang et al., 2014; Lan et al., 2014, 2015a,b) and the diversification of multicellular eukaryotes (e.g., TE D Yuan et al., 2011; Chen et al., 2014; Xiao et al., 2014a) An unresolved issue related to this sedimentary succession is the regional stratigraphic correlation of pre-Sturtian strata across the Nanhua basin or more specifically, the stratigraphic relationship EP between the Banxi Group in Hunan Province and the Liantuo Formation in Yangtze AC C Gorges area Some researchers suggested that the Liantuo Formation is equivalent or partially equivalent to the Banxi Group (e.g., Wang and Li, 2003; Jiang et al., 2003b, 2011; Zhang et al., 2008a,b; Du et al., 2013; Lan et al., 2015a), while others argued that the deposition of the Banxi Group was earlier than the Liantuo Formation (e.g., Xue et al., 2001; Wang et al., 2009b; Yin and Gao, 2013; Gao et al., 2013; Lin et al., 2013; Liu et al., 2015a) The settlement of current debate requires further age constraint on both units Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT Recent geochronological studies indicate that the Liantuo Formation was deposited between ca 780 Ma and 714 Ma (Du et al., 2013; Lan et al., 2015a) The deposition of the Banxi Group was considered to begin at ca 820 Ma (Wang and Li, 2003; RI PT Zhang et al., 2008b; Wang et al., 2009a; Zhang et al., 2012b), but the top boundary age of this unit remains debated, either at ca 720 Ma (Zhang et al., 2008a; Wang et al., 2012a; Bai et al., 2015) or at 780 Ma (Liu et al., 2015a) The upper age of the Banxi SC Group also provides constraint on the onset of the Sturtian glaciation because the M AN U Banxi Group in the Nanhua basin is overlain by the Jiangkou diamictites correlative with the Sturtian glaciation (e.g., Lan et al., 2014) The Sturtian glaciation was thought to have initiated synchronously at ca 715 Ma in at least three continents including South China, Oman and Canada (Bowring et al., 2007; Macdonald et al., TE D 2010; Lan et al., 2014), which is consistent with the prediction of the "snowball" Earth hypothesis (Hoffman and Schrag, 2002) However, two SHRIMP U-Pb ages of 778.4 ± 5.2 Ma and 785 ± 11 Ma were recently reported from the tuff bed/breccia at EP the base of the Chang'an/Jiangkou diamictites in the Nanhua basin (Gao et al., 2013; AC C Liu et al., 2015a), challenging the synchroneity of the Sturtian glaciation In this paper, we present the result of LA-ICPMS U-Pb dating analyses of detrital zircons from the middle and topmost Wuqiangxi Formation of the Banxi Group at Siduping, western Hunan Province (Fig 1) The new ages, in combination with available zircon U-Pb ages in literature, provide age constraints on the Banxi Group and the synchroneity of the Sturtian glaciation We also discuss the provenance of Wuqiangxi sandstone based on the age distribution and regional stratigrahic Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT correlation of pre-Sturtian strata in the Nanhua basin Geological background and sampling RI PT The Nanhua basin was formed as a result of intracontinental rifting along the Jiangnan Orogen that marks the amalgamation of the Yangtze and Cathaysia blocks (Fig 1A; Li et al., 1999; Wang and Li, 2003; Li et al., 2008a,b; Li et al., 2010a,b; SC Zhao and Cawood, 2012) The rift basin evolved into a passive continental margin M AN U during the late Neoproterozoic (e.g., Jiang et al., 2003b, 2011) or a failed rift (e.g., Wang and Li, 2003; Yao et al., 2015) Alternatively, the Nanhua basin has been interpreted as a back-arc basin (Zhou et al., 2002a; Zhao et al., 2011; Zhang et al., 2012a) TE D Unconformably overlying the metamorphic rocks of early Neoproterozoic Sibao/Fanjingshan/Lengjiaxi groups, the middle–late Neoproterozoic strata were well outcropped in Hubei–Hunan–Guizhou–Guangxi provinces of the Nanhua Basin and EP are conventionally divided into three parts (Fig 2A; Jiang et al., 2011; Xiao et al., AC C 2014b): pre-glacial deposits, glacial and interglacial deposits and post-glacial deposits The pre-glacial deposits are characterized by siliciclastic rocks intercalated with volcanic rocks, including the Liantuo Formation in Hubei Province, the Banxi Group in Hunan Province, the Xiajiang Group in Guizhou Province and the Danzhou Group in Guangxi Province (Fig 2A) The relationship of these units, particularly the Liantuo Formation and the Banxi Group, remains controversial (e.g., Du et el., 2013; Gao et al., 2013; Lan et al., 2015a; Liu et al., 2015a) and will be the focus of this Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT paper Two intervals of glacial diamictites were documented in the Nanhua basin: the older (Sturtian) Jiangkou Group (or their equivalents) and the younger (Marinoan) Nantuo Formation (e.g., Zhang et al., 2008b; Jiang et al., 2011; Lan et al., 2014) The RI PT Jiangkou glaciation was further divided to the earlier Chang'an glaciation and the later Gucheng glaciation (Zhang et al., 2011; Lan et al., 2015b), although it is quite likely that these two “glaciations” are diachronous stratigraphic record of the same SC glaciation (Jiang et al., 1996, 2003b, 2011) Interglacial manganese-bearing M AN U shale/siltstone of the Datangpo/Xiangmeng Formation dated at ca 663–654 Ma (Zhou et al., 2004; Yin et al., 2006; Zhang et al., 2008c; Liu et al., 2015b) is sandwiched between the Jiangkou Group and Nantuo Formation In proximal shelf sections, the Jiangkou diamictites are largely missing probably due to erosion (Fig 2A) TE D Post-glacial mixed carbonates and shales of the Doushantuo Formation are dated as from 635 Ma to ≤551 Ma (Condon et al., 2005; Zhang et al., 2005; An et al., 2015) and carbonates/cherts of the Dengying/Liuchapo formations extend to Cambrian EP These Ediacaran strata have been intensively investigated due to preservation of AC C abundant fossils, including acanthomorphic acritarchs, macroscopic algae, possible animal embryos and metazoans (e.g., Yin et al., 2007; Yuan et al., 2011; Chen et al., 2014; Liu et al., 2014; Xiao et al., 2014a) The study section at Siduping is located in the Zhangjiajie area, western Hunan Province, South China (Fig 1) The Banxi Group in this locality is divided into the Madiyi and Wuqiangxi formations (Fig 2B) The Wuqiangxi Formation is more than 1000 m thick and is composed of purple and gray sandstone, siltstone and pebbly Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT sandstone Abundant wavy (Fig 3A) and cross beddings (Fig 3B) have been observed in this unit, indicative of predominately littoral environment The Wuqiangxi Formation is overlain by a 1-m-thick sandy diamictite with parallel beds (Fig 3C) RI PT This unit, locally termed as the Dongshanfeng Formation, was considered to be correlative with the Chang'an Formation (Jiang et al., 1996), which is unconformably overlain by massive diamictites of the Nantuo Formation (Fig 3D) The missing of SC the interglacial deposits in this section may have been resulted from the erosion M AN U during the Nantuo glaciation Two samples were collected from the Wuqiangxi Formation for LA-ICPMS dating Sample WQX13-1 is dark-purple, medium-grained sandstone from the middle part of the Wuqiangxi Formation, about 425 m below the top the Wuqiangxi Formation Sample WQX13-2 is dark-green, fine-grained TE D sandstone immediately below the Chang'an/Dongshanfeng diamictite Analytical methods EP Rock samples (~ kg in weight) were crushed in a steel jaw crusher, and standard AC C density and magnetic separation techniques were used to separate heavy minerals Zircons were hand-picked under binocular microscope Representative grains, together with standard zircon 91500, were mounted in an epoxy resin and then polished to expose the longitudinal section of crystals Prior to analysis, transmitted and reflected light photomicrographs as well as cathodoluminescence (CL) images were used to reveal the zircon grains’ internal structures and to help selecting appropriate analytical spots Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT U-Pb dating of zircon grains was conducted using LA-ICPMS at the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Beijing) Laser sampling was performed using a Coherent’s RI PT GeoLasPro-193nm system A Thermo Fisher’s X-Series ICP-MS instrument was used to acquire ion-signal intensities Helium was applied as a carrier gas Argon was used as the make-up gas and mixed with the carrier gas All data were acquired on SC zircon in single spot ablation mode at a spot size of 32 µm with Hz frequency M AN U SRM610 was used to optimize the LA-ICPMS instrument, and as an external standard for determination of trace elements Zircon 91500 was used as an external standard for U-Th-Pb isotope ratios (Wiedenbeck et al., 2004) Meanwhile zircon Mud Tank was used as a monitoring standard for each analysis Time-dependent drifts of TE D U-Th-Pb isotope ratios were corrected using a linear interpolation for every five analyses according to the variations of 91500 Each analysis incorporated a background acquisition of approximately 20s (gas blank) followed by 50s data EP acquisition from the sample Off-line selection and integration of background and AC C analytical signals, time-drift correction and quantitative calibration of trace elements, and U-Pb dates were performed by ICPMSDataCal (Liu et al., 2008a) and plotted using Isoplot 3.0 (Ludwig, 2003) Common Pb correction was carried out using the Andersen method (Andersen, 2002) Results 158 zircon grains were dated, and the results are listed in supplementary Table A1 Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT Zhang, Y.Z., Wang, Y.J., Fan, W.M., Zhang, A.M., Ma, L.Y., 2012b Geochronological and geochemical constraints on the metasomatised source for the Neoproterozoic (similar to 825 Ma) high-mg Mg volcanic rocks from the Cangshuipu area (Hunan Province) along the Jiangnan RI PT domain and their tectonic implications Precambrian Research 220, 139-157 Zhang, Y.Z., Wang, Y.J., Zhang, Y.H., Zhang, A.M., 2015b Neoproterozoic assembly of the Yangtze and Cathaysia blocks: Evidence from the Cangshuipu Group and associated rocks along SC the Central Jiangnan Orogen, South China Precambrian Research 269, 18-30 M AN U Zhao, G.C., 2015 Jiangnan Orogen in South China: Developing from divergent double subduction Gondwana Research 27, 1173-1180 Zhao, G.C., Cawood, P.A., 2012 Precambrian geology of China Precambrian Research 222, 13-54 TE D Zhao, J.H., Zhou, M.F., 2007 Neoproterozoic adakitic plutons and arc magmatism along the western margin of the Yangtze Block, South China Journal of Geology 115, 675–689 Zhao, J.H., Zhou, M.F., 2009a Secular evolution of the Neoproterozoic lithospheric mantle EP underneath the northern margin of the Yangtze Block, South China Lithos 107, 152–168 AC C Zhao, J.H., Zhou, M.F., 2009b Melting of newly formed mafic crust for the formation of Neoproterozoic I-type granite in the Hannan region, South China The Journal of Geology 117, 54–70 Zhao, J.H., Zhou, M.F., Yan, D.P., Zheng, J.P., Li, J.W., 2011 Reappraisal of the ages of Neoproterozoic strata in South China: No connection with the Grenvillian orogeny Geology 39, 299-302 Zhou, C., Tucker, R., Xiao, S., Peng, Z., Yuan, X., Chen, Z., 2004 New constraints on the Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT ages of Neoproterozoic glaciations in south China Geology 32, 437-440 Zhou, H.W., Li, X.H., Wang, H.R., Li, J., Li, H.M., 2002c U-Pb Zircon Geochronology of Basic volcanic rocks of the Yingyangguan Group in Hezhou, Guangxi, and its tectonic RI PT implications Geological Review 48, 22-25 (in Chinese with English abstract) Zhou, M.F., Kennedy, A.K., Sun, M., Malpas, J., Lesher, C.M., 2002b Neoproterozoic accretion of Rodinia Journal of Geology 110, 611–618 SC arc-related mafic intrusions along the northern margin of South China: implications for the M AN U Zhou, M.F., Ma, Y.X., Yan, D.P., Xia, X.P., Zhao, J.H., Sun, M., 2006a The Yanbian Terrane(Southern Sichuan Province, SW China): a Neoproterozoic arc assemblage in the western margin of the Yangtze Block Precambrian Research 144, 19–38 Zhou, M.F., Yan, D.P., Kennedy, A.K., Li, Y.Q., Ding, J., 2002a SHRIMP U-Pb zircon TE D geochronological and geochemical evidence for Neoproterozoic arc-magmatism along the western margin of the Yangtze Block, South China Earth and Planetary Science Letters 196, 51-67 Zhou, M.F., Yan, D.P., Wang, C.L., Qi, L., Kennedy, A., 2006b Subduction-related origin EP ofthe750 Ma Xuelongbao adakitic complex (Sichuan Province, China): implications for the AC C tectonic setting of the giant Neoproterozoic magmatic event in South China Earth and Planetary Science Letters 248, 286–300 Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT Figure and Table captions Figure (A) The Neoproterozoic tectonic framework of South China The Nanhua basin separated the Yangtze Block in the northwest from the Cathaysia Block in SC (red star marks the Siduping section in Fig 1A) RI PT southeast (after Jiang et al., 2003b) (B) Simplified geological map of the study area Figure (A) Generalized shallow-water to deep-water transect of the middle to late M AN U Neoproterozoic strata in South China (modified after Xiao et al., 2014b) (B) Middle Neoproterozoic stratigraphic section in Siduping, western Hunan Province, South China The Banxi Group is subdivided into the Madiyi Formation in the lower part and the Wuqiangxi Formation in the upper part Stratigraphic position of samples is TE D marked in the stratal column Figure Field photos of the upper Wuqiangxi Formation at the Siduping section (A) EP Wavy bedding in purple sandstone of the Wuqiangxi Formation; (B) planar cross bedding in pebbly sandstone of the Wuqiangxi Formation; (C) the sandy diamictite AC C above the top of the Wuqiangxi Formation that is possibly remains of the Sturtian glacial diamictites; (D) the boundary between the sandy diamictite and the Nantuo Formationdiamictite The interglacial Datangpo/Xiangmeng Formation is entirely missing in this section Coins as scale in (A) and (B) are cm in diameter Hammer and pencil as scales in (C) and (D) are 33 cm and 15 cm in length, respectively Figure Representative CL images of zircon grains from sample WQX-13-1 (upper Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT panel) and WQX-13-2 (lower panel); most of them show clear oscillatory growth zonation RI PT Figure U-Pb concordia plots of zircons from sample WQX-13-1 (A, B) and WQX-13-2 (C, D) The ellipses show 1σ errors SC Figure Relative probabilities of zircons from sample WQX-13-1 (A, B) and M AN U WQX-13-2 (C, D) of the upper Wuqiangxi Formation The youngest age group from sample WQX-13-2 gives a weighted mean 206 Pb/238U ages of 714.6±5.2 Ma For zircons with ages >1000 Ma, 207Pb/206Pb ages are used For zircons younger than 1000 TE D Ma, 206Pb/238U ages are used Figure Chondrite normalized REE patterns of zircons from sample WQX-13-1 (A) and WQX-13-2 (B) The REE patterns show that the zircons display negative Eu AC C origin EP anomalies, positive Ce anomalies, and HREE enrichments, indicating magmatic Figure Stratigraphic correlation of the Neoproterozoic (pre-Sturtian) strata across the Nanhua basin in South China, with most of the published U-Pb ages shown in each stratigraphic column The ages were shown in different colors according to the analyzing methods (red: SIMS; blue: SHRIMP; green: LA-ICPMS; brown: TIMS) Stt.010.Mssv.BKD002ac.email.ninhd 77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77t@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.33.44.55.54.78.65.5.43.22.2.4 22.Tai lieu Luan 66.55.77.99 van Luan an.77.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.37.99.44.45.67.22.55.77.C.33.44.55.54.78.655.43.22.2.4.55.22 Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an ACCEPTED MANUSCRIPT Figure Correlation of the U-Pb relative probability plots of detrital zircons from the Banxi Group and its equivalents (the Liantuo Formation, Xiajiang Group and Danzhou Group) Data sources: Banxi Group (Wang et al., 2010b and this study); RI PT Liantuo Formation (Cui et al., 2014); Xiajiang Group (Wang et al., 2010a); Danzhou Group (Wang and Zhou, 2012) SC Table A1 LA-ICPMS U-Pb analyses of zircons from the Wuqiangxi sandstone in M AN U Siduping section, western Hunan, South China Errors are presented in 1σ The data AC C EP TE D with concordance