Quaternary Science Reviews 173 (2017) 145e160 Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Mid-Holocene palaeoflood events recorded at the Zhongqiao Neolithic cultural site in the Jianghan Plain, middle Yangtze River Valley, China * ** Li Wu a, b, , Cheng Zhu c, , Chunmei Ma c, Feng Li d, Huaping Meng e, Hui Liu e, Linying Li a, Xiaocui Wang d, Wei Sun c, Yougui Song b a College of Territorial Resources and Tourism, Anhui Normal University, Wuhu 241002, PR China b State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xi'an 710054, PR China c School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, PR China d State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography & Limnology, CAS, Nanjing 210008, PR China e Hubei Provincial Institute of Cultural Relics and Archaeology, Wuhan 430077, PR China article info abstract Article history: Palaeo-hydrological and archaeological investigations were carried out in the Jianghan Plain in the Received 2 December 2016 middle reaches of the Yangtze River. Based on a comparative analysis of modern flood sediments and Received in revised form multidisciplinary approaches such as AMS14C and archaeological dating, zircon micromorphology, grain 5 July 2017 size, magnetic susceptibility, and geochemistry, we identified palaeoflood sediments preserved at the Accepted 13 August 2017 Zhongqiao archaeological site. The results indicate that three palaeoflood events (i.e. 4800e4597, 4479 Available online 31 August 2017 e4367, and 4168-3850 cal. yr BP) occurred at the Zhongqiao Site. Comparisons of palaeoflood deposit layers at a number of Neolithic cultural sites show that two extraordinary palaeoflood events occurred in Keywords: e Palaeoflood the Jianghan Plain during approximately 4900 4600 cal. yr BP (i.e.mid-late Qujialing cultural period) Neolithic Site and 4100-3800 cal. yr BP (i.e. from late Shijiahe cultural period to the Xia Dynasty). Further analysis of Climatic event the environmental context suggests that these flooding events might have been connected with great Jianghan Plain climate variability during approximately 5000e4500 cal. yr BP and at ca. 4000 cal. yr BP. These two Yangtze River palaeoflood events were closely related to the expansion of the Jianghan lakes driven by the climatic Mid-Holocene change, which in turn influenced the rise and fall of the Neolithic cultures in the middle reaches of the Yangtze River. Other evidence also suggests that the intensified discrepancy between social development and environmental change processes (especially the hydrological process) during the late Shijiahe cul- tural period might be the key factor causing the collapse of the Shijiahe Culture. The extraordinary floods related to the climatic anomaly at ca. 4000 cal. yr BP and political conflicts from internal or other cultural areas all accelerated the collapse of the Shijiahe Culture. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction et al., 2012a,b, 2014; Innes et al., 2014; Chen et al., 2015; Lillios et al., 2016). Palaeofloods and their temporal scale have become With the progress into the research on Past Global Changes an extremely important research component of the PAGES program (PAGES) (Yang et al., 2011; Zhu et al., 2012; IPCC, 2013; Lowe and (Baker, 2002, 2006, 2008; Yu et al., 2003, 2010; Huang et al., 2010, Walker, 2013; Roberts, 2014; Govin et al., 2015; Zolitschka et al., 2011a, 2012; Xia, 2012; Greenbaum et al., 2014; Liu et al., 2015; Wu 2015; Chen et al., 2016; Rao et al., 2016; Zhou et al., 2016), et al., 2016). Long-term flood records can be obtained through studies on the impact of catastrophic environmental events on studying palaeoflood sediments (Luo et al., 2013; Yin, 2015; Sharma human civilization during the Holocene have received more and et al., 2017). Palaeoflood deposits preserved in the stratigraphical more attention (Turney and Brown, 2007; Zong et al., 2007; Wu context of archaeological sites provide several new ideas: first, natural alluvium without any cultural relics has been found in some archaeological sites, most of which have the characteristics of al- * Corresponding author. College of Territorial Resources and Tourism, Anhui luvial flooding; second, in terms of the chronology of palaeoflood Normal University, Wuhu 241002, PR China. sediments, AMS14C and other archaeological dating of the ** Corresponding author. unearthed objects often corroborate each other, offsetting the E-mail addresses: [email protected] (L. Wu), [email protected] (C. Zhu). http://dx.doi.org/10.1016/j.quascirev.2017.08.018 0277-3791/© 2017 Elsevier Ltd. All rights reserved. 146 L. Wu et al. / Quaternary Science Reviews 173 (2017) 145e160 difficulties in dating of some palaeoflood sediments due to the 2. Geographical settings and stratigraphy absence of organic matters therein. Located in the middle reaches of the Yangtze River, the Jian- The Zhongqiao Neolithic site is situated on the first terrace of the ghan Plain is not only an important “land of milk and honey” in north bank of Lake Changhu, along the border with Jingzhou City China, but also one of the areas suffering from the most serious (Fig. 1). This site, with an area of 21,000 m2, is located 60 km south flood events (Zhou and Tang, 2008). Flood disasters were frequent of Shayang County. The central geographical coordinate of the site after the Holocene (Zhou, 1986, 1992; Yu et al., 2009), exerting a is 303101400N, 1122700000E, and the elevation of its surface is profound impact on social development, settlement changes, and 27e29 m above sea level (a.s.l.). The Zhongqiao Site extends NE-SW human livelihood in this region, and these now provide fertile along the border zone of the loess terrace and downhill between materials for studies of prehistoric flood events, the development the northwestern edge of Jianghan Plain and the Jingshan Moun- of human civilization, and changes in the relationship between tains. According to the microrelief, approximately two major step man and land through archaeological stratigraphy. Although in platforms can be found at the site. The second step platform, past studies (Zhou, 1986, 1992; Zhu et al., 1997; Liu, 2000; Xie extending from the northeast to the centre of the site with an area et al., 2007), some progresses have been made, two problems of 4000 m2,is1e2 m higher than the first step platform and con- still exist in the study of prehistoric floods in the Jianghan Plain. tains the main burial areas; the first step platform, extending from First, previous studies of prehistoric floods in the Jianghan Plain the southwest to the centre of site, with an area of 16,000 m2, have failed to make full use of the stratigraphic information from contains the main living areas and dips to the lake shore from west numerous archaeological sites in the region. A total of 1362 to east. archaeological sites from the Paleolithic Age to the Warring States The Zhongqiao Site contains the most complete Neolithic cul- time have been found in and around the Jianghan Plain (Wang, tural information discovered in the Jianghan Plain since the 2007; Li et al., 2011b). A large number of charcoals or plant res- archaeological rescue excavations of the Yangtze-to-Hanjiang River idues in the strata of these sites can be used for dating (Zhou, Water Diversion Project. It contains Daxi, Qujialing, and Shijiahe 1986; Zhu et al., 1997, 2005, 2014). Thus, the age of cultural cultural layers from the middle reaches of the Yangtze River in the layers of these sites can be determined by the method that Neolithic Age, and there are many charcoal deposits in each cultural combines AMS14C dating and excavated artifacts (Zhu et al., 2005, layer. The archaeological team designated by the Hubei Provincial 2008; Huang et al., 2011a,b, 2017). Then the exact time of Cultural Relics Department excavated the Zhongqiao Neolithic site palaeoflood deposits, silt, and other intermittent layers between between October 2009 and January 2010, clarifying the cultural the cultural layers can be derived (Zhu et al., 2005; Wu et al., connotations and the distribution of the site and unearthing nearly 2012a,b). However, up to now there were only some progresses 20 Neolithic housing remains and urn burials as well as over 100 on the historical floods based on the research of natural fluvio- tools, utensils, and other cultural relics, and large number of lacustrine strata in the Jianghan Plain (Xie et al., 2007; Li et al., Neolithic pottery fragments. There are a total of 49 excavation units 2009; Zheng et al., 2015). Second, the Shijiahe Culture, which belonging two districts (i.e. I and II) in this Neolithic site. These was the last well-developed culture close to the threshold of units are numbered as follows: I) T0101~T0103, T0201~T0205, civilization in the middle reaches of the Yangtze River, dis- T0301~T0306, T0401~T0407, T0415, T0505~T0509, T0515, T0516, appeared around 4000 yr BP (Wu and Liu, 2004; Liu and Feng, T0605~T0610, T0613, T0614, T0711~T0713, T0813, T0913, T1013, 2012; Li et al., 2013), but there has been no definite conclusion T1113; II) T0101~T0103, T0201, T0202 (Cultural Heritage Bureau of on the exact age and environmental causes of its demise. Some Hubei Province and Hubei Provincial Management Bureau of Japanese and Chinese archaeologists believe that the widespread South-to-North Water Transfer, 2014). All of the unit profiles are weakened summer monsoon and arid climatic events in Eurasia in the same stratigraphic sequence. There is only a difference in the around 4000 cal. yr BP may have led to the decline of the Shijiahe excavation depth of the unit profile. It is noteworthy that the Culture in the middle reaches of the Yangtze River during the late Zhongqiao Site has natural alluvium layers from both the early- Neolithic Period (Yasuda et al., 2004; Hunan Provincial Institute of middle and late periods of the Shijiahe culture.