Precambrian Research 225 (2013) 7–28 Contents lists available at ScienceDirect Precambrian Research journa l h omepa g e: www.elsevier.com/locate/precamres Carbon isotope chemostratigraphy and sedimentary facies evolution of the Ediacaran Doushantuo Formation in western Hubei, South China Maoyan Zhu a,∗ , Miao Lu a , Junming Zhang a , Fangchen Zhao a , Guoxiang Li a , Yang Aihua b , Xin Zhao a,c , Meijuan Zhao a,d a State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China b Department of Earth Sciences, Nanjing University, Nanjing 210008, China c Paleontological Institute, Shenyang Normal University, Shenyang 110034, China d Geological Science Research Institute, Shengli Oilfield, Sinopec, Dongying, Shangdong 257000, China a r t i c l e i n f o Article history: Received 28 April 2011 Received in revised form 27 July 2011 Accepted 29 July 2011 Available online 6 August 2011 Keywords: Ediacaran Doushantuo South China Carbon isotope Stratigraphy Chemostratigraphy a b s t r a c t The Doushantuo Formation of South China, consisting of intercalated siliciclastic and carbonate rocks which exhibit considerable variation in thickness and sedimentary facies, is one of the key sedimen- tary units in the world for understanding Ediacaran geobiological processes. However, stratigraphic correlation and sedimentary facies evolution of the Doushantuo Formation remain controversial. Sed- imentary facies analysis of the well-known sections of the Yangtze Gorges area and new sections in northern Yichang, western Hubei indicate that the Doushantuo succession in the Yangtze Gorges area was deposited in an offshore intra-shelf basin within the Yangtze platform. In contrast, the Doushantuo Formation in the northern Yichang area which is characterized by one or a few phosphate-rich horizons represents deposition on the subtidal or intertidal shelf, and so is similar to the succession in the Weng’an area (central Guizhou Province). The carbon isotope profiles of the different sections exhibit significant variation, which is interpreted to result from facies differences. Sequence and high-resolution carbon iso- tope stratigraphy have clarified problematic correlations and the temporal relationship between fossil assemblages of the Doushantuo Formation on the Yangtze platform. The results confirm that a prominent negative ı 13 C carb excursion (BAINCE, nadir down to -5‰) in the middle portion of the second sequence of the Doushantuo Formation is a widely traceable event. BAINCE together with three other ı 13 C carb excur- sions, namely CANCE at the base, WANCE near the first sequence boundary near the middle, and DOUNCE at the top of the Doushantuo Formation, constitute a complete carbon isotope profile for the Doushan- tuo Formation that reflects contemporaneous seawater and so serves as a reference chemostratigraphic profile for global stratigraphic correlation and for evaluating the chemical evolution of seawater during the Ediacaran Period. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The Ediacaran Doushantuo Formation of South China covers the critical time interval from 635 to 551 Ma, immediately following the global end-Neoproterozoic ice age (Condon et al., 2005) and has become a focus of global research on Neoproterozoic geol- ogy and paleobiology over the past decade. This is because (1) it yields rich and exquisitely preserved multicellular fossils, includ- ing microscopic embryos (Li et al., 1998; Xiao et al., 1998; Chen et al., 2006, 2009; Yin et al., 2007), macroscopic algae (Xiao et al., 2002; Yuan et al., 2011 and references therein) and Ediacara-type soft-bodied fossils (Zhu et al., 2008); and (2) although relatively ∗ Corresponding author. Tel.: +86 25 83282159; fax: +86 25 83282159. E-mail address: myzhu@nigpas.ac.cn (M. Zhu). condensed (ca. 100–200 m, or even less than 100 m in some sec- tions), it comprises both carbonate and siliciclastic strata exposed across a large area of South China which exhibit various facies rang- ing from shallow marine shelf to deep marine basin (Zhu et al., 2003, 2007a). The Doushantuo Formation, therefore, currently pro- vides the best rock succession worldwide for global subdivision and correlation of Ediacaran stratigraphy and for reconstruction of Ediacaran palaeoenvironments using multiple geochemical prox- ies. However, despite intense debates on the paleobiology of the Doushantuo fossils (e.g. Bengtson and Budd, 2004; Chen et al., 2004; Bailey et al., 2007; Xiao et al., 2007) and interpretation of geo- chemical signatures reported from the Doushantuo Formation (e.g. Jiang et al., 2003; Bao et al., 2008; McFadden et al., 2008; Li et al., 2010; Zhou et al., 2010), stratigraphic correlation and sedimentary facies reconstruction of the Doushantuo Formation on the Yangtze platform remains problematic (Vernhet, 2007; Zhu et al., 2007a; Bristow et al., 2009; Vernhet and Reijmer, 2010; Jiang et al., 2011). 0301-9268/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.precamres.2011.07.019