Environmental Changes and Human Activities at a Fortified Site of The
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Quaternary International 438 (2017) 189e197 Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint Environmental changes and human activities at a fortified site of the Liangzhu culture in eastern China: Evidence from pollen and charcoal records * Xiaocui Wang a, b, Duowen Mo c, Chunhai Li a, Shi-Yong Yu d, Bin Xue a, , Bin Liu e, Hui Wang f, Chenxi Shi g a State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China b University of Chinese Academy of Sciences, Beijing 100049, China c Laboratory for Earth Surface Processes, College of Erban and Environmental Sciences, Peking University, Beijing 100871, China d School of Geography, Geomatics, and Planning, Jiangsu Normal University, Xuzhou 221116, China e Zhejiang Provincial Institute of Relics and Archaeology, Hangzhou 310026, China f Institute of Archaeology, Chinese Academy of Social Sciences, Beijing 100710, China g National Educational Examinatios Authority, Beijing 100087, China article info abstract Article history: Liangzhu culture represents the culmination of the Neolithic culture in the Yangtze Delta. Two archae- Received 12 December 2016 ological trenches (LZ-N and LZ-W) from a fortified archaeological site in close proximity to Hangzhou, Accepted 3 May 2017 eastern China, were excavated and studied. The sediments were analyzed to provide vegetation and fire Available online 9 May 2017 records for the reconstruction of environmental change and human impact during the past 5000 years. Pollen data reveal that mixed evergreen-deciduous subtropical broadleaved forests may have developed Keywords: around lakes or swamps in this area. Abundant charcoal detritus and Gramineae pollen with a size Liangzhu culture >38 mm indicate that rice agriculture flourished during 5000e4500 cal yr BP. Low concentrations of Mojiaoshan site > m Pollen charcoal detritus and Gramineae pollen with a size 38 m suggest that the site was abandoned after Charcoal 4500 cal yr BP. Pollen and charcoal data from the LZ-N section suggest that this area has experienced a Vegetation weakened human activity during the late period of the Liangzhu culture (between 4500 and 4300 cal yr Human activity BP), implying that the demise of the Liangzhu culture was a prolonged process rather than a short-lived event. © 2017 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction the culmination of the Neolithic culture in the lower Yangtze River area. This culture is well known for its flourished rice-based agri- As one of the cradles of the Chinese culture, the Neolithic culture culture, making of diverse and sophisticated jade articles, advanced in the lower Yangtze River area has experienced a long and complex pottery technology with diversified types and decoration, the evolutional process during the Holocene. Beginning with the highly complex social structure reflected by large-scale architec- Shangshan culture (11.4e8.4 kyr BP), the Neolithic culture in this tural engineering (Zhejiang Provincial Institute of Cultural Relics area has experienced several periods such as the Majiabang culture and Archaeology, 2008; Zheng et al., 2009; Fuller et al., 2009; Qin (7.0e5.9 kyr BP), Songze culture (5.9e5.3 kyr BP), and Liangzhu et al., 2011). However, the Liangzhu culture terminated mysteri- culture (5.3e4.3 kyr BP). Of these cultural periods, the Liangzhu ously and the regional culture was replaced by a less developed culture is the last stage of the prehistoric culture, which represents culture known as the Guangfulin/Maqiao culture (Chen et al., 1997; Zhu et al., 2003; Chen, 2005; Zong et al., 2011a). Therefore, scru- tinizing the reasons behind the termination of the Liangzhu culture is of great importance for better understanding the rise and fall of * Corresponding author. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, regional Neolithic culture and the emergence of early Chinese Nanjing 210008, China. civilization. E-mail address: [email protected] (B. Xue). http://dx.doi.org/10.1016/j.quaint.2017.05.001 1040-6182/© 2017 Elsevier Ltd and INQUA. All rights reserved. 190 X. Wang et al. / Quaternary International 438 (2017) 189e197 The termination of the Liangzhu culture has received great Archaeological excavations reveal that this site appears to be the attention and it is still a matter of debate. Previous studies have central township of the Liangzhu culture in Yangtze Delta, repre- shown that the disappearance of the Liangzhu culture may have senting the highest stage of the Liangzhu culture in the Yangtze been ascribed to a catastrophic environmental event such as rapid River area (Zhejiang Provincial Institute of Cultural Relics and climate cooling (Yu et al., 2000; Innes et al., 2014), marine trans- Archaeology, 2008; Liu and Wang, 2014). As such, this site is of gression (Stanley and Chen, 1996; Chen et al., 2008), or flash great importance for unraveling the reason and process of the flooding (Zhang et al., 2004, 2005; Zong et al., 2012; Long et al., termination of the Liangzhu culture. 2014; Liu et al., 2015). However, evidence for such a rapid termi- Previous studies have focused on the structure and provenance nation of the Liangzhu culture is scarce. (Zhejiang Provincial Institute of Cultural Relics and Archaeology, The Mojiaoshan archaeological site is located in close proximity 2008; Hu et al., 2013), the internal and external layout of the wall to Hangzhou (Fig. 1), East China. It is the first Neolithic fortified surrounding the Mojiaoshan site (Zhejiang Provincial Institute of township has ever discovered in the lower Yangtze River area. Cultural Relics and Archaeology, 2015), the age when the earthen Fig. 1. (A) Map showing the study area; (B) location of profiles LZ-N and LZ-W(redrawn from Fei and Chen, 2011; Shi et al., 2011; Zong et al., 2011a). X. Wang et al. / Quaternary International 438 (2017) 189e197 191 dike was constructed (Zhang et al., 2014; Liu et al., 2015), as well as earlier than when the site was settled. The LZ-W profile has been the hydroclimatic condition and palaeoecological background (Li described by Shi et al. (2011). Their work was based on AMS 14C et al., 2010; Shi et al., 2011; Liu et al., 2014b) of the Liangzhu cul- dating on bulk organic matter. In this study, we conducted detailed ture. There have been a few studies on the age constraint on the AMS 14C dating of these two profiles on charcoal and plant remains timing of the construction and abandonment of the wall at this site. that are believed to be free of old carbon. For example, base on archaeological evidence, archaeologists infer Five samples on charcoal and one sample on plant macrofossil that the wall was built no later than the late Liangzhu period were collected from the lower part of the two profiles (below (Zhejiang Provincial Institute of Cultural Relics and Archaeology, 120 cm) and submitted for AMS 14C dating. In order to obtain 2008), while AMS 14C and OSL dating suggests that the wall was reliable ages for the upper section, additional six samples on pollen built during 4.8e4.5 cal kyr BP (Liu et al., 2015). However, there is concentrates at the depth of 86e144 cm from the LZ-N profile was still a key question about the environmental context in which the dated using the AMS 14C method. Previous work revealed that the site was abandoned (Li et al., 2010; Shi et al., 2011; Long et al., 2014; age of pollen concentrates is slightly older than the actual age due Liu et al., 2014b, 2015). Here we aim to reconstruct vegetation to the introduction of pre-aged organic carbon in the fluvial setting history, environmental changes, and human activities at the (Stanley and Chen, 2000; Stanley and Hait, 2000; Li et al., 2014). Mojiaoshan site based on detailed AMS 14C dating, pollen and Paired samples of charcoal and pollen concentrates were taken charcoal analyses, which in turn may provide an ecological context from the depth of 120e122 cm and 142e144 cm of the LZ-N profile and a chronological framework for the abandonment of this to determine the age offset between these two kinds of materials. Neolithic Liangzhu township. Standard hydrofluoric (HF) acid method (Faegri and Iversen, 1989) was used for the extraction of pollen concentrates. The AMS 14C 2. Regional setting dating was conducted at Beta Analytic Inc. All results were cali- brated using the IntCal13 tree-ring dataset (Talma and Vogel, 1993; The Mojiaoshan site is located at the township of Pingyao, Reimer et al., 2013). The result was expressed as the 2s (95%) Hangzhou, Zhejiang Province (Fig. 1). It is surrounded by the Dax- confidence intervals. iongshan Mountain on the south, the Yaoshan and Nanshan A total of 58 pollen samples were taken at 2 cm intervals from Mountains on the west, and the Dazheshan Mountain on the north. the depth of 158e40 cm of the LZ-N profile, while 42 samples were This area is drained by several creeks such as North Tiaoxi, Middle collected at 2 cm intervals from the depth of 196e125 cm of the LZ- Tiaoxi, and South Tiaoxi, which originate in the west of the Tian- W profile. Note that the depth of 125e30 cm of the LZ-W profile mushan Mountain and merge into East Tiaoxi River, running down represents the post-Liangzhu cultural deposits. Therefore, samples the Tianmushan Mountain from southwest to northeast and dis- were taken at 10 cm intervals from this section due to the less charging into the Taihu Lake. importance of this section to our study. Standard HF method was Regulated by the subtropical monsoon, the regional climate used for the pretreatment of the samples (Faegri and Iversen, 1989; exhibits a significant seasonal variability.