In order to explore the interactions among human activities, hydroclimate, and sea-river-lake level fluctuations in the mid-lower Yangtze Valley since the Neolithic, this study, based on AMS 14C and OSL dating of the Core JH002 along with geophysics, geochemistry, and microfossils, reconstructs the hydroclimate changes, sedimentary evolution, and human adaptations in the Jianghan Plain since 13,000 cal a BP. The results show that solar radiation controlled the intensity of the East Asian monsoon. Meanwhile, 5 wet-dry climate alternation phases and 30 flood-prone periods were identified. Hydroclimates and sea level changes affected the regional environment evolution and human activities. During 13,000-11,700 cal a BP (transition of Paleolithic and Neolithic), high-energy riverbed environments and extreme floods constrained human activities, with the riverbed linked to the deeply incised valleys from the Last Glacial Maximum and low sea levels during the Younger Dryas period. During 11,700-7800 cal a BP (early Neolithic), the elevated river and lake water levels caused by warm-wet conditions and rising sea levels created wetlands, facilitating human activities. The earliest evidence of human activities in the interior of Jianghan Plain dates back to about 11,300 cal a BP. From 7800 to 4000 cal a BP (mid-late Neolithic), frequent typical floods and a turbulent delta environment collectively hindered human activities. During 4000-3000 cal a BP (Xia-Shang Dynasties), high water level and expansion of Paleo-Yunmeng Lake Group limited human activities such as rice cultivation. Since 3000 cal a BP, improved water management allowed Chu people to coexist with floods, leading to the prosperity of Chu Culture. This study offers critical insights into the interactions between regional environment changes, ancient culture evolution, and human adaptations in the Yangtze region.

To explore the relationship between the global cooling, westerlies, and central Asian aridity, we report similar to 1.1 Ma local sedimentary environment changes according to physical-chemical parameters from an 800-m core (KT11) from the Kashgar region in the western Tarim Basin, China. Grain size end-member (EM) modelling is employed to quantify the processes of sediment transport and deposition. Four end members with modal values of 272 mu m, 144 mu m, 45.6 mu m and 12.7 mu m were extracted and explained 97.9% of the variance in the grain size data, corresponding aeolian dynamics, river energies, delta development and pedogenesis/long-term suspension components transported by wind or water, respectively. Four dominant sedimentation types, including lacustrine facies, delta facies, fluvial facies, and aeolian dunes, were identified through lithology and grain size frequency curves. The 1.1 Ma sedimentary successions experienced delta deposits interbedded with fluvial and aeolian deposits and lacustrines (1.1-0.6 Ma), alternating fluvial and aeolian facies with the occurrence of deltas and lacustrines (0.6-0.15 Ma), and aeolian facies interbedded with deltas and fluvial facies (0.15 Ma-present). Stepwise drying sedimentary conditions and enhanced desertification indicated by increasing rubidium/strontium ratios and proportion of aeolian sands, and decreasing total organic carbon since the past 1.1 Ma, implied intensified westerlies, likely resulted from ice volume expansion and ongoing global cooling according to geological record comparison and simulations during the Last Glacial Maximum compared to preindustrial conditions, which may have controlled the expansion of the permanent deserts in inland Asia. These persistent drying trends and intensified westerly circulation in arid regions during glacial periods after the mid-Pleistocene Transition indicated by larger amplitudes of aeolian sand proportion than prior to 0.6 Ma are similar to those in the interior monsoonal Asia, where the larger-amplitude of median grain size indicated enhanced Asian winter monsoon intensity and drier glacials.

In the Jianghan Plain, known as the province of thousands of lakes, monsoon precipitation-induced floods carrying large amounts of sediments can shape the depositional landscape, particularly after frequent river flooding. Therefore, the sediments document abundant information on climate change and its interaction with the fluviolacustrine system and paleoflooding. To date, late Holocene paleoflood records are limited, as continuous paleoflood archives are scarce. Here, using grain size end-members and sensitive components in combination with element records from the JH001 sediment core in the Jianghan Plain, nine continuous paleoflood regimes were identified during 3400-3000, 2750-2550, 2050-1820, 1800-1650, 1550-1500, 1350-1100, 1050-1000, 800-750, and 620-600 cal yr BP, respectively. Exploration of the climatic driving factors on flood regimes indicated a good agreement among paleoflood regimes and El Nin & SIM;o-Southern Oscillation (ENSO)-related hydrological records in the Middle Yangtze Valley (MYV) and reconstructed ENSO records. This suggests that ENSO is the dominant influence on flood occurrence in the Jianghan Plain. Strong ENSO activity exerted a southward shift in the subtropical high in the western Pacific and produced a long-lasting rainbelt in the mid-lower Yangtze Valley, which induced the occurrence of floods in the Jianghan Plain. The evolution pattern of sedimentary environment demonstrated that the floods led to river overflow and overbank expansion, even causing the rivers to divert and bifurcate. The overflow channels carried and deposited silt sediments in the floodplain, which shaped the specific alluvial-lacustrine landscape of the Jianghan Plain. Our results indicate that the grain size of core sediments is sensitive to the occurrence of paleofloods, and that ENSO-related paleofloods significantly influenced the fluviolacustrine sedimentary evolution. These findings are highly useful for regional flood planning and environmental protection in the eastern Jianghan Plain in the context of global warming.

植硅体形态测量学是植硅体研究的重要方向之一,随着学科交叉研究的深入,植硅体形态测量学在植物分类与生态学、环境考古学、全球变化与生态响应等领域得到快速发展.综合已有研究成果表明,长鞍型植硅体形态测量学在日本、中国的竹亚科属一级竹类生态学具有独特的指示作用,而扇型和长鞍型形态测量学在中国西南西双版纳竹亚科木本竹子属一级分类中具有重要的参考价值;稻亚科扇型形态测量学可以有效区分籼稻与粳稻,且扇型鱼鳞状纹饰与颖壳双峰植硅体形态测量学结合可以准确判别亚洲栽培稻与普通野生稻;黍亚科树状表皮长细胞形态测量学被成功运用到区分中国西北黍和粟及其亲缘物种的关系,葫芦科南瓜属刻面球型植硅体形态测量学揭示了野生种、半驯化种和驯化种之间植硅体形态大小及其关系,证实南美洲低地地区早全新世出现的南瓜驯化历史;中国东北不同环境条件下的禾本科羊草、芦苇植硅体形态测量学研究反映了陆生植物对全球变化的生理生态响应,为研究陆地生态系统对全球变化的响应及古环境重建提供了重要参考.

In order to explore the impacts of past climate changes on the origin and evolution of Lake Poyang, the biggest freshwater lake in China, eight periods of palaeoenvironmental changes were constructed to depict the history of climate change over the past 3500 years based on the palynological records and carbon isotopic excursions. The climate regime was associated with the presence of a deciduous and evergreen broad-leaved forest/a mixed needle broad-leaved forest and strong/weak solar variability. Palaeohydrology change reconstructed by the percentage of aquatics and stable carbon isotopes demonstrated that the wet episode was associated with the developed lacustrine facies and enhanced El Niño–Southern Oscillation (ENSO) activities. The presence of the united open lake (Lake Poyang) during 2000–1200 cal. a BP was linked to a long wet period caused by the strong ENSO activities. At the decadal-centennial timescales, climate changes together with the ENSO activities might have played a great role on the regional hydrological condition and sedimentary evolution in southern Lake Poyang. The correlations of the palaeotemperature and palaeohydrology with the multi-proxy data from the Northern Hemisphere all suggest that palaeotemperature change with the monsoon intensity is linked to the solar variations, but palaeohydrology change has a striking consistency with the ENSO activities. The distinct hydrothermal diversification (warm-wet, warm-dry, cold-wet, cold-dry) revealed by the palaeotemperature and palaeohydrology changes will provide important clues about the origin and evolution of Lake Poyang in the Holocene and a better understanding of the interactions between solar radiation, ENSO activity and lake deposition in the middle Yangtze River Valley.

为深刻理解江汉盆地第四纪新构造运动、气候变化与盆地沉积响应的关联,利用沔阳凹陷区第四纪典型钻孔样品进行系统岩石学、年代学与沉积学研究,首次建立了盆地东部沉积中心区可对比的地层序列.利用岩性、粒度、磁组构分析重建了研究区140万年以来依次经历的河流相、河湖交替相、湖相、河湖交替相、湖相、泛滥平原相演化过程.区域构造、沉积、气候资料综合对比表明,响应于新构造沉降,江汉盆地第四纪以来存在3大成湖期,即Qp2/Qp1之交、Qp.与Qh中后期(古云梦泽),其中MIS3以来古湖发育是新构造沉降与异常强盛夏季风的耦合,且湖相沉积的独特环境为盆地高砷地下水的形成提供了重要的物质条件.不仅为第四纪钻孔地层划分对比提供可靠基础资料,也为盆地地下资源调查与环境规划保护提供重要参考.