Middle Holocene marine flooding and human response in the south Yangtze coastal plain, East China

Abstract

Coastal flooding catastrophes have affected human societies on coastal 15 plains around the world on several occasions in the past, and are threatening 21 th 16 century societies under global warming and sea-level rise. However, the role of 17 coastal flooding in the interruption of the Neolithic Liangzhu culture in the lower 18 Yangtze valley, East China coast has been long contested. In this study, we used a 19 well-dated Neolithic site (the Yushan site) close to the present coastline to 20 demonstrate a marine drowning event at the terminal stage of the Liangzhu culture 21 and discuss its linkage to relative sea-level rise. We analysed sedimentology, 22 chronology, organic elemental composition, diatoms and dinoflagellate cysts for 2 23 several typical profiles at the Yushan site. The field and sedimentary data provided 24 clear evidence of a palaeo-typhoon event that overwhelmed the Yushan site at ~2560 25 BCE, which heralded a period of marine inundation and ecological deterioration at 26 the site. We also infer an acceleration in sea-level rise at 2560-2440 BCE from the 27 sedimentary records at Yushan, which explains the widespread signatures of coastal 28 flooding across the south Yangtze coastal plain at that time. The timing of this mid-29 Holocene coastal flooding coincided with the sudden disappearance of the advanced 30 and widespread Liangzhu culture along the lower Yangtze valley. We infer that 31 extreme events and flooding accompanying accelerated sea-level rise were major 32 causes of vulnerability for prehistoric coastal societies.33 34 35 39 (Woodruff et al., 2013). The vulnerability of low-lying coastal plains and deltas 40 across the world is further exacerbated due to human-induced sediment starvation and 41 land sinking (Syvitski et al., 2009; Giosan et al., 2014). The west Pacific Ocean coast 42 is one of the most vulnerable regions in the world because it is characterized by active 43 tropical cyclones (Woodruff et al., 2013) and, in recent decades, its rate of relative 44sea-level rise is three times higher than the global mean (Nicholls and Cazenave, 3 45 2010). In the densely-populated Yangtze delta, East China (Fig. 1), models under 46 future climate scenarios predict an increase in flood risk from extreme events and 47 relative sea-level rise by 150% to 400% in the next 50 years (Tessler et al., 2015). In 48 fact, Typhoon Fitow (the strongest October typhoon making landfall in China for over 49 60 years) in 2013 caused flooding to a depth >0.5 m across most of the Yaojiang 50Plain, south east of the Hangzhou Bay (Fig. 1C). There is thus clearly an urgent need 51 for integrated research on sea-level rise, extreme events, coastal flooding and human 52 response. 53Coastal flooding is not a new threat. The fact that the south Yangtze coastal 54 plains (Fig. 1B) hold relative thick and rich archaeological records, preserved in 55 marine and deltaic flood basin sediments (Zong et al., 2007;Zheng et al., 2012), is 56 direct witness of past flooding of these areas during human occupation. N...

Paleoenvironmental Evolution and Human Activities at the Hejia Site on the Ningshao Coastal Plain in Eastern China

“…Mn, which is mainly enriched in an oxidizing environment, was at a high level during this period. The well consistency between the oxide layer and the peak of Mn FIGURE 6 | Records of the study area: (A) the climate fluctuation curve on the south bank of the Yangtze River Delta (Chen et al, 2005), (B) the relative sea-level change in the study area (Wang et al, 2018), and (C)-(L) χ lf , Cr/Cu, Mn, Ca, P, micro-charcoal, macro-charcoal concentrations, Tree and Shrubs percentage, Poaceae (>37 μm) and Artemisia percentage, respectively (this study). (M)-(N) mean grain size (Mz) and Sr/Ba ratios in profile T0103W of the Xiawangdu Site (Huang et al, 2021).…”

“…The early and middle Liangzhu Culture was the heyday of the Liangzhu Culture. Studies show that the prosperity occurred when the sea-level was lower and the climate was cool and dry (Chen et al, 2005;Wang et al, 2018). During this period, human beings gained a spacious living field, and the development of the Liangzhu Culture reached its peak.…”

“…Previous studies state that the Liangzhu Culture, as the paramount one of prehistoric cultures in the lower reaches of the Yangtze River (Wu et al, 2012), developed a mature rice farming system when the primitive society was disintegrating and the embryonic state of the country was forming (Li et al, 2010c;Wang et al, 2017). The Liangzhu Culture disappeared at approximately 4,300 cal a BP, and several studies attribute that it was caused by the catastrophic events, such as rapid climate cooling, transgression, and floods (Stanley and Chen, 1996;Innes et al, 2014;Kajita et al, 2018;Wang et al, 2018;Wang et al, 2020). Some studies also suggest that the demise of the Liangzhu Culture may be the result of social factors (Zong et al, 2011).…”

Ancient Maya wetland fields revealed under tropical forest canopy from laser scanning and multiproxy evidence

“…Wetland fields and canals make up one such system, and similar systems are widespread across indigenous Mesoamerica and the neotropics (12–19), as well as in ancient China (20), Angkor Wat (21, 22), New Guinea (23), and in modern Africa (24). Wetland systems have been keys for human subsistence, and their sediments and stratigraphy can provide evidence for human responses to droughts, floods, and sea level change (21, 25–27), as well as global scale human-induced environmental change that may amount to an Early Anthropocene (28, 29). Nonetheless, research on Maya wetland farming that started with fervor in the 1970s (30–40) languished in controversy and doubt after the 1990s (27, 41).…”

The changes of hydrological environment recorded in the section of Tianluoshan Site in Zhejiang Province

“…例如, 钱塘江及环 太湖流域的良渚文化此时消失被马桥文化所取代, 黄 河 中 下 游 龙 山 文 化 突 然 衰 落 演 化 成 后 来 的 岳 石 文 化 [10,11] . 在我国东部沿海地区, Wang等人 [12] 利用鱼山遗 址剖面中综合指标分析研究认为在4.5~4.2 cal ka BP发 生了重大沿海洪涝灾害. He等人 [13] 近年来, 基于硅藻 [21,22] 、XRF(X射线荧光光谱分 析)元素扫描 [23,24] 、粒度等的综合指标分析已经成为研 究海-陆环境变迁和地貌环境演化的重要手段.…”