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Recent interpretations of the archaeology of domesticated rice evolution and the development of agriculture in the Lower Yangzi Valley are being informed by new genetic, palaeoenvironmental, archaeological and archaeobotanical data. This paper explores current views on early rice production in the region and attempts to expand the discourse to provoke exploration of new and modified questions. Rice-specific botanical through large-scale ecological issues and causality are examined. This paper argues that understanding rice domestication and production, although important, should not be the exclusive goal of research on early agriculture in the Yangzi Valley. Despite the preliminary nature of the investigations at Kuahuqiao (c. 8000–7000 cal. BP), evidence of resource management, and potential domesticated resources or their ancestors that includes pig (Sus scrofa), peach (Prunus persica), apricot (P. armeniaca), Japanese apricot (P. mume), foxnut (Euryale ferox) and water chestnut (Trapa spp.) underscore the need to broaden the scope of inquiry on early food/resource production. The complexities of the archaeological and environmental record in the Yangzi valley indicate that nuanced, complex explanations for rice domestication and agricultural origins rather than deterministic, single cause explanations are necessary in order to move forward. [ABSTRACT FROM AUTHOR]

The period from the late third millennium BC to the start of the first millennium AD witnesses the first steps towards food globalization in which a significant number of important crops and animals, independently domesticated within China, India, Africa and West Asia, traversed Central Asia greatly increasing Eurasian agricultural diversity. This paper utilizes an archaeobotanical database (AsCAD), to explore evidence for these crop translocations along southern and northern routes of interaction between east and west. To begin, crop translocations from the Near East across India and Central Asia are examined for wheat (Triticum aestivum) and barley (Hordeum vulgare) from the eighth to the second millennia BC when they reach China. The case of pulses and flax (Linum usitatissimum) that only complete this journey in Han times (206 BC–AD 220), often never fully adopted, is also addressed. The discussion then turns to the Chinese millets, Panicum miliaceum and Setaria italica, peaches (Amygdalus persica) and apricots (Armeniaca vulgaris), tracing their movement from the fifth millennium to the second millennium BC when the Panicum miliaceum reaches Europe and Setaria italica Northern India, with peaches and apricots present in Kashmir and Swat. Finally, the translocation of japonica rice from China to India that gave rise to indica rice is considered, possibly dating to the second millennium BC. The routes these crops travelled include those to the north via the Inner Asia Mountain Corridor, across Middle Asia, where there is good evidence for wheat, barley and the Chinese millets. The case for japonica rice, apricots and peaches is less clear, and the northern route is contrasted with that through northeast India, Tibet and west China. Not all these journeys were synchronous, and this paper highlights the selective long-distance transport of crops as an alternative to demic-diffusion of farmers with a defined crop package. [ABSTRACT FROM AUTHOR]

In this paper, we use geoarchaeological and paleoenvironmental data from three localities in the Yellow River Valley, China – Taosi, Sanyangzhuang, and the Yiluo Valley – to argue that human activity in the mid- to late-Holocene contributed to large-scale changes in the behavior of the Yellow River and that these changes were of sufficient magnitude to bend the arc of China’s history. Massive anthropogenic landscape transformation from the later Neolithic into the early Dynastic periods, especially in the Chinese Loess Plateau, increased sedimentation in the Yellow River requiring intensive investment in flood control features to protect an ever-growing population. As the Yellow River channel aggraded, channel gradients became increasingly steep, and avulsions occurred with greater frequency and consequence. Flooding reached an apogee in the first decades of the Common Era when a massive avulsion of the Yellow River ca. 14–17 CE caused the river to shift to the south and east of its former channel. This avulsion and the catastrophic flooding that followed triggered the collapse of the Western Han dynasty. The Yellow River – known as ‘China’s Tribulation’ – has been seen as a natural scourge that afflicts the inhabitants of the fertile North China Plain. However, when viewed in an Anthropocene perspective, it is evident that China’s Tribulation largely is the result of human manipulation of the environment. [ABSTRACT FROM AUTHOR]

This paper investigates the interaction between groundwater and groundwater-dominated Crescent Spring in an aeolian sand environment to determine the drainage source of groundwater for the lake using hydraulic gradient and isotope analysis methods. The precipitation is found to have an insignificant effect on the lake in an arid climate environment. Hydrogen and oxygen isotopic evidence presents at least two aquifer contributions that recharge 87% and 13% water supply of the lake, respectively. The flow direction of groundwater is theoretically established based on the hydraulic gradient and isotope analysis methods. [ABSTRACT FROM PUBLISHER]

In this paper, we summarize the Holocene environmental history of the lower Yangtze region, east China, based on the sedimentary records and microfossil diatom, pollen, fungal and charcoal data that were published in the past two decades. We then examine the linkage between changes in the coastal environment and the development of rice agriculture in the region, with reference to the available archaeological evidence and historical archives. Based on the sedimentary and archaeological evidence, we conclude that during the early Holocene sea-level movements and sedimentary processes significantly changed the region’s landscape from an open, brackish water environment to a largely enclosed, wetland system. This newly established freshwater marsh environment provided a habitat favourable to rice agriculture. The early Neolithic farmers took the opportunity presented to them and started rice cultivation in locations where freshwater wetland systems were established. During the middle Holocene, environmental conditions were largely stable, and the coastal wetlands evolved slowly. Environmental change was only a supportive player in the Neolithic cultural processes, because the Neolithic people were able to adapt to these changes and took advantages of the newly emerging marsh land for food collection and production. Around 4200 years ago, the prosperous Liangzhu society fell, but there is no evidence to suggest the fall was related to a significant environmental change. The coastal environment continued to evolve slowly during the late Holocene. But this period saw rapid technological development in irrigation and flood protection, and the environmental factor was reduced to background noise. Throughout the Holocene, the main strategy taken by the Neolithic people to cope with environmental change was migration to find better food sources. Along with this strategy was the development of technology in landscape management to ensure a more reliable food production in addition to food collection through hunting, gathering and fishing. [ABSTRACT FROM AUTHOR]

The paper explores the use of Resilience Theory to provide an improved theoretical framework for the analysis of socio-ecological interactions over decadal—millennial timescales. It identifies landscape system behaviour through analysis of proxy records for land use, erosion and monsoon intensity over the past 3000 years in the Erhai lake-catchment system, Yunnan, SW China. Analysis of the records shows the possibility of alternative steady states in the landscape, as expressed by the relationship between land use and erosion. In particular, a period of agricultural expansion ~1400 cal. yr BP triggered rapid gully erosion that led to the formation of an eroded landscape state that has existed since ~800 cal. yr BP to the present day. Comparison of detrended time-series data suggests that over 3000 years erosion and land use should be considered 'slow' processes relative to the 'faster' monsoon intensity and flooding. In the past, the effects of high monsoon variance on flooding have been suppressed by paddy farming and the maintenance of terraced field systems. Mapping the Adaptive Cycle on to the millennial record of land use and erosion suggests that the modern landscape may be approaching a 'conservation' phase characterized by minimum resilience. Such 'historical profiling' of modern landscapes offers a new dimension for hypothesis testing, for the development and testing of simulation models and for the creation of appropriate management strategies. [ABSTRACT FROM AUTHOR]

This paper is a response, both to Fuller et al.'s recent criticism of Chinese research on rice domestication, as lacking evidence, and to their argument for the beginning of rice domestication around 4000 BC in the lower Yangzi River. We first survey previous publications that discuss the process from wild rice collection to rice domestication in China, and then examine early rice remains from the perspectives of rice morphology and archaeological context. We focus on three aspects: the timing of the initial rice domestication in the Yangzi River region; the earliest presence of domesticated rice in the Lower Yangzi and Huai River regions; and the implications of changes in rice grain sizes in archaeological assemblages. We also discuss problems relating to the presence of immature rice remains in the archaeological record, grain size increase and overall grain shape, which are three of the criteria used by Fuller et al. for distinguishing domesticated from wild rice. Based on published data and our research on rice, we demonstrate that by the early Holocene (9000 cal. BP), Neolithic people in both north and south China may have been harvesting wild rice and initiating rice cultivation that eventually led to domestication. [ABSTRACT FROM AUTHOR]

The lower Yangtze, eastern China, was colonized by several Neolithic and Bronze Age cultures giving rise to possibly the highest concentration of prehistoric sites in the world. Early Neolithic cultures in the delta region cultivated rice (Oryza sativa) and agricultural developments appear to have occurred throughout the Neolithic with abrupt socio-economic changes possibly associated with the terminal Neolithic. Given the extensive history of environmental exploitation and well-preserved archaeological sites, the Yangtze delta is an ideal setting to explore the complex interactions between humans and their environment. Multiproxies of environmental changes, namely pollen, charcoal and phytoliths, in a 14C AMS-dated sequence of sediments from an exposed profile at Qingpu, Yangtze delta, were investigated. 14C AMS dating indicates that the age range of the sedimentary sequence analysed is from c. 1800 to 6000 BP, and therefore encompasses the terminal Neolithic and subsequent Bronze Age in the region. This paper reviews this sediment-based evidence in the light of current understanding of human-environment interactions during a critical phase of the development of the Yangtze delta and associated human cultures. [ABSTRACT FROM AUTHOR]

Stalagmite laminae provide a high-resolution geological record of climate change. In this paper, moving spectral analysis is used to analyse a stalagmite lamina thickness record to study climatic variability. It was found that the dominant cycles of the lamina thickness sequence are 2, 3.3, 5–6, 10–12, 14–18, 133 and 194 years. Some of the cycles are the same as the cycles of modern climatic indices, such as the QBO (Quasi Biennial Oscillation) of 2 years, the QTO (Quasi Triple-year Oscillation) cycle of about 3.5 years, the QFO (Quasi Five-year Oscillation) cycle of 5–6 years and the QEO (Quasi Eleven-year Oscillation) cycle of 11 years. It was also found that there are different dominant cycles in different time periods. Usually, the dominant cycles are stronger in wet periods when the microlaminae are thicker. In dry periods, the microlaminae are thinner and the power of the dominant cycles is also weaker. Another feature is that the power of the dominant cycles and their long-term periods and frequencies appear to change. These phenomena are important for understanding the climatic changes in Beijing area over the last 1 ka. [ABSTRACT FROM AUTHOR]

A set of paleoflood slack water deposit (SWD) beds was identified within slope clasts at the Jinpingcun (JPC) site in the Jingyuan–Jingtai reaches of the upper Yellow River gorges based on sedimentary criteria and analytical results. Paleoflood hydrology methods were applied to reconstruct paleoflood events in the Jingyuan–Jingtai reaches. The paleoflood peak stages were calculated based on the highest end-point elevations of the SWDs. The HEC-RAS model and optically stimulated luminescence dating enabled robust paleo-discharge estimates to be calculated between 12,750 and 16,310 m3/s for paleoflood events that occurred during 3200–3000 a BP. The peak discharges, including gauged and historical flood data at the Lanzhou gauge station and the reconstructed paleoflood peak discharges at the JPC site, were input for flood frequency analysis. These paleo-hydrological approaches can also be applied to other regions in the Yellow River gorges. Furthermore, the ages of the paleoflood events correspond well with the known climatic events at 3100 a BP during Holocene climatic variability. These findings are significant for flood risk estimation, in the assessment of water sources in dryland environments, and in understanding the interactions between hydrological systems and climatic change in arid and semi-arid regions of the upper Yellow River in China. [ABSTRACT FROM AUTHOR]

The Yellow River catchment of northern China was central to the rise of complex societies from the first Neolithic farmers through to early states and empires. These cultural developments brought with them rising populations and increasing intensity of land-use. This region provides an important record of landscape changes that mark the development of the Anthropocene in China. Geoarchaeological research in the middle reaches of the Yellow River catchment of Henan Province and eastward to the Si River drainage of Shandong Province illustrates human impact on vegetation and hydrological systems dating back at least until the middle Neolithic Yangshao Period in the mid-Holocene, ca. 7000 yr BP. This research provides geomorphological evidence that early human impact began in the Yangshao period with deforestation, soil erosion, and increased alluviation in the upper catchment of the Yiluo River. The increased alluviation allowed small-scale Neolithic farmers to intensify and supplement their production with rice paddy farming. Further east along the Si River of Shandong Province, Neolithic Dawenkou farmers were intensifying production by taking advantage of the already moist floodplains, but had little impact on the surrounding forests and hillslopes. At the beginning of the Zhou Period (ca. 1000 BCE), farmers along the Si River at Qufu began to intensify production by digging canals into the floodplain, and deforestation of the hillslopes led to the beginnings of widespread floods and silty floodplain buildup, culminating in the massive destructive floods of the later Han Period characterized by thick sand beds. [ABSTRACT FROM AUTHOR]

We report the results of a study of the Qionghai Lake watershed, located on the southeastern edge of the Qinghai–Tibetan Plateau, China, designed to investigate the effects of human activity on changes in soil erosion intensity, debris flow activity and lacustrine sedimentation. The results indicate that the mean denudation rate of the watershed was about 0.82 mm/yr during the Holocene. However, since 1952, the rate has increased to 1.82 mm/yr, accompanied by a greatly increased sedimentation rate in Qionghai Lake. The increased denudation rate was accompanied by increases in population and the related intensified exploitation of land resources, including deforestation and an increase in the area of cultivated land. In addition, the increasing rate of denudation and lacustrine sedimentation is closely linked to the increased frequency of flooding and debris flows in the watershed. Based on our results, we estimate that the longevity of Qionghai Lake is about 1200 years in the case of natural evolution; however, this is reduced to 540 years in the context of continued intensive human activity in the region. These findings are important for the mitigation of mountain hazards such as debris flows and for the promotion of sustainable economic development in the Qionghai Lake area. They also provide a basis for obtaining an improved estimate of changes in denudation rate on the southeastern edge of the Qinghai–Tibet Plateau. [ABSTRACT FROM AUTHOR]

The relation between climate change and historical rhythms has long been discussed; however, this type of study still faces the lack of high-resolution data of long-term socio-economic processes. In this study, we collected 1101 items of direct and proffered evidence from 24 Chinese fiscal and economic history books written by leading contemporary scholars. By analysing the semantics of words, we reconstructed a 2130-year-long fiscal sequence with decadal resolution to express the phase transition of fiscal soundness for approximately 21 dynasties in China. Our reconstruction shows four relatively sufficient stages and three relatively deficient stages, with several secondary stages lasting 60 or 160 years on average within each large stage, from 220 bc to ad 1910. Then, the fiscal association with climate change was analysed. The results show that the fiscal crisis was more likely to occur in cold-dry climatic scenarios. Both temperature and precipitation displayed more significant effects on the fiscal fluctuation within the long term, particularly for temperature. In short, fiscal decline had a 10-year lag in response to decreasing precipitation, whereas influence of decreasing temperature on the fiscal balance might be through amplifying already deteriorating fiscal conditions. Regional differences existed in the influence of precipitation on the fiscal balance. The precipitation in the Northern China Plain and in the Jiang-Huai area had more significant effects on the fluctuation of the dynastic fiscal balance than on that in the Jiang-Nan area. In particular, the dynastic finance was more sensitive to the change in the precipitation in the Northern China Plain because of its special geographical, economic and social backgrounds. [ABSTRACT FROM AUTHOR]

High-resolution macroscopic charcoal and sediment analysis was used to reconstruct fire history and environmental changes from three loess-paleosol profiles on the semi-arid loess tableland landscape during the Lateglacial period and the Holocene. Analysis of charcoal concentrations, influx, and the ratios of particle-size classes (from which changes in charcoal taphonomy over time are inferred) in the profiles show spatially coherent patterns of change that relate to regional variations in climate. Effective moisture variability on century to millennial timescales and regional differences in fuel availability appear to be the most important controls on fire from the Lateglacial period to the mid Holocene (12,000–3100 yr BP). Conversely, asynchronous fire patterns during the late Holocene appear to indicate regional and temporal variations as well as changing intensities of human activity. Land use intensified in the region during the late Holocene, when the climate became more arid, and a distinct increase in charcoal concentration then indicated an unprecedented increase in biomass burning. The increase in fire activity occurs in the recent loess layer (L0) and the surface soil (TS) consistent with the establishment of irrigated farming for cereal cultivation in the southern part of the study region about 3100 yr BP. Broad-scale land reclamation was extended to the loess tableland region about 2170–1730 yr BP (during the Qin-Han Dynasty period), and the rapidly decreasing charcoal concentration in the accumulated topsoil (at depths of less than 20 cm) at the CCY site since 1500 yr BP is consistent with the development of terrace farming in the northern part of the study region at that time. In summary, the evolution of fire history in the study profiles across the region is closely related to (1) gradients in humidity; (2) spatial and temporal variability in the distribution and intensity of human land use; and (3) the buildup of burnable biomass, among which there was a nonlinear complex relationship during the Holocene. Increased efforts to synthesize and analyze multiple paleo-environmental records and to combine these with multiproxy evidence are needed to understand wildfire history as well as human land use and social cultural development across the region in depth. [ABSTRACT FROM PUBLISHER]

It has been suggested that late-Holocene human activities caused the increase in atmospheric methane (CH4) concentration that otherwise would have been a naturally decreasing trend. As one of the places where rice farming originated, China has been considered to play a significant role in pre-industrial changes in atmospheric CH4 concentrations. To establish the climatic context since the first rice cultivation and to evaluate the relative roles of monsoon climate and rice cultivation on late Holocene CH4 rise, we synthesized climate data from China to examine the Holocene trends in monsoon precipitation. The results show high monsoon rainfall from 10,000 to 7000 years ago, and declining precipitation in the late Holocene as shown by most reconstructions. The decreasing trend in monsoon precipitation is consistent with that in other north tropical monsoon regions, and is opposite to the trend in CH4 concentrations. After ruling out several other natural factors and estimating CH4 emissions from early rice farming, we conclude that the late-Holocene methane increase has been significantly influenced by the expansion of early rice paddy fields during the period of declining monsoon precipitation. [ABSTRACT FROM AUTHOR]

Understanding the mid-Holocene dynamics of the East Asian monsoon (EAM) is integral to improving models of the Holocene development of the global climate system. Here we reconstruct the mid-Holocene EAM history from the Pearl River estuary, southern China, using bulk organic carbon isotopes (δ13C), total carbon to total nitrogen (C/N) ratios and total organic carbon (TOC) concentration. Sedimentary δ13C, C/N and TOC are potentially good indicators of changes in monsoonal precipitation strength. Sediments buried during a period of high precipitation exhibit a high proportion of terrigenous material, and have low δ13C and high C/N, and vice versa during a period of low precipitation. Results suggest a general decreasing trend in monsoonal precipitation from 6650 to 2150 cal. yr BP because of the weakening Northern Hemisphere insolation most likely related to the current precession circle. Superimposed on this trend are apparent dry–wet oscillations at centennial to millennial timescales most likely in response to solar activity. Mismatches between our δ13C record and results from the Dongge Cave in southern China at millennial timescales may indicate that the δ13C from the Pearl River estuary reveals changes in precipitation over a broader area than the δ18O from Dongge Cave. [ABSTRACT FROM AUTHOR]

Sedimentary records of the Holocene extraordinary floods were investigated in the upper reaches of the Weihe River, a major tributary in the middle Yellow River basin. Palaeoflood slackwater deposits (SWD) were identified at several sites on the riverbanks. These clayey silt beds are inserted into the Holocene aeolian loess-soil profiles and slope clastic deposits. They have recorded the extraordinary palaeoflood events which occurred between 3200 and 3000 yr BP as dated by OSL method and checked by the archaeological remains of the Neolithic and Bronze Age retrieved from the profile. The minimum flood peak discharges were estimated at between 22 560 and 25 960 m3/s by using palaeohydrological methods. It is 4.5–5.0 times the largest gauged flood (5030 m3/s) that has ever occurred since 1934. The palaeoflood slackwater deposits were found inserted into the pedostratigraphic boundary between the late-Holocene loess (L0) and the mid-Holocene Luvisol (S0) in the riverbank profile. This indicates that the extraordinary flood events were synchronous with the pedogenic regression at the end of the mid-Holocene climatic optimum. The climatic proxies from the studied profile and the correlative profiles in the river valley and the Loess Plateau show that the pedogenic regression was forced by climatic aridity and intensified dust storms and dust falls in connection with monsoonal shift over the Yellow River basin at about 3100 yr BP. The extraordinary flood events were documented not only on the Weihe River, but also on the mainstream and other tributaries of the Yellow River. These suggest that both extraordinary floods and droughts were parts of the climatic variability during the monsoonal shift. These findings are of great importance in understanding the interactions between hydrological system and climatic change in the semi-arid and subhumid regions of the world. [ABSTRACT FROM AUTHOR]

We analyzed spatial and temporal growth variations of Qilian Junipers over the northeastern Tibetan Plateau (TP) during the period 1450—2001 by applying the empirical orthogonal function (EOF) technique to seven moisture-sensitive tree ring-width chronologies. The first three principal components together explain 78.21% of the total variance. The first principal component (PC1) accounts for 51.58% of the total variance, and represents consistent tree-growth variations in the northeastern TP. The second EOF mode reveals an opposite structure for the southern and northern parts of the northeastern Tibetan Plateau, reflecting the effect of huge topography and associated atmospheric circulation on tree-growth anomalies. The third EOF mode represents an opposite structure for the eastern and western parts of the northeastern Tibetan Plateau, possibly indicating the influence of different branches of atmospheric circulation system in this area. The EOF analysis results of instrumental precipitation data resemble those derived from the seven regional chronologies, providing further support that tree growth is a good indicator of regional precipitation variations. According to the PC1, dry conditions occurred in AD 1450—1510, 1631—1739, 1765—1833, 1866—1883 and 1921—1947, whereas periods of relatively wet years are identified for AD 1511—1630, 1740—1764, 1834—1865, 1884—1920 and 1948—2001. During the past 550 years, 28 years with extreme regional growth depressions was identified. These ring-width extremes generally occurred in century-scale dry periods. The years 1467, 1484, 1641, 1721, and 1928 with extreme tree-growth reductions in the northeastern TP are coeval with severe drought events in eastern China. In addition, the dry intervals or extreme growth depressions generally coincided with cold periods in the northeastern TP and vice versa, implying that the probability of occurrence of wet events in the northeastern TP will be higher in the future under the ongoing global warming. [ABSTRACT FROM AUTHOR]

The earliest direct dates of wheat in East Asia come from Donghuishan in Gansu Province, China. Few other dates of wheat in East Asia are direct dates. The previous direct dates at Donghuishan were obtained from wheat without secure context. New samples were taken from a stratigraphic profile at Donghuishan and directly dated. The wheat remains are earlier than any other directly dated wheat east of the Xinjiang Autonomous Region, but considerably later than the previously dated specimen from the same site. These new dates, from the early second millennium bc, are the earliest evidence of significant wheat and barley production and show that the Hexi Corridor played a critical role in the introduction of wheat to China. [ABSTRACT FROM AUTHOR]

High-resolution oxygen isotope (δ18O) profiles of six stalagmites from Sanbao Cave in Hubei province, central China, established with 1413 oxygen isotope data and 65 230Th ages, provide a continuous history of East Asian Summer Monsoon (EASM) intensity for the period from 13-0.2 thousand years before present (ky BP, relative to AD 1950). The δ18O record includes four distinct stages in the evolution of the EASM: (1) an abrupt transition (∼11.5 ky BP) into the Holocene; (2) a period of gradual increase in monsoon intensity (11.5-9.5 ky BP); (3) the maximum humid period (9.5-6.5 ky BP); and (4) a period of gradual decline in monsoon intensity (6.5-0.2 ky BP). Comparison of Sanbao with regional records of comparable resolution reveals that the timing of the beginning and end of the Holocene Optimum (as defined by the minimum in δ18O) was similar in the Indian and East Asian monsoon systems. This supports the idea that shifts in the monsoon tied to shifts in the mean position of the Inter-Tropical Convergence Zone (ITCZ) may control monsoon intensity throughout the entire low-latitude region of Asia on orbital timescales. This observation also supports the idea that the fluctuations in δ18O recorded across southern Asia reflect broad changes in the monsoon, as opposed to local meteoric precipitation. The EASM records from Sanbao largely follow orbital-scale insolation changes, yet exhibit similar variability to Greenland ice core δ18O on millennial to centennial scales during the early to middle Holocene (&#x03B3l = 0.94). [ABSTRACT FROM AUTHOR]

A 700-year semi-quantitative history of diffuse groundwater recharge in the Badain Jaran Desert (Inner Mongolia) is proposed on the basis of solute data from multiple unsaturated zone groundwater profiles using mass balance of chloride to establish recharge rates and profile chronologies. Four relatively humid (1330-1430, 1500-1620, 1700-1780 and 1950-1990) and three relatively arid phases (1430-1500, 1620-1700 and 1900-1950) are discernable across the profiles. The recharge history broadly reflects multidecadal to centurial timescale precipitation changes in the northern Tibetan Plateau and suggests that variations in East Asian Summer Monsoon intensity affect desert recharge rates. Uncertainties in the records owing to assumptions about the Cl inputs are examined by comparing deterministic and stochastic Cl input scenarios. Such records are valuable for assessing spatial aspects of climate changes in the region, as well as for informing sustainable water resource management strategies for northwestern China's drylands. [ABSTRACT FROM AUTHOR]

Drought variability of the Tibetan Plateau is an important component across the Asian monsoon. Long-term information about the history of drought is, however, limited because the instrumental records are short. In this study we developed a tree-ring chronology of Sabina tibetica from northern Tibet and used it to reconstruct the history of drought variation for the region. Response analysis shows that water availability in spring and early summer is the main factor limiting the radial growth of Sabina trees in northern Tibet. A May-June Palmer Drought Severity Index (PDSI) reconstruction for the past 500 years (r = 0.66, P < 0.0001) shows that the seventeenth century was the driest century, whereas the eighteenth, nineteenth and twentieth centuries were the wettest. The sixteenth century was not significantly different from the long-term mean. The major periods of reconstructed dry conditions include AD 1600-1610, 1617-1624, 1630-1632, 1639-1654, 1665-1681 and 1692-1701. Significant wetter periods were found to be AD 1520-1532, 1702-1705, 1716-1722, 1752-1758, 1839-1857 and 1928-1943. The drought rhythm in northern Tibet has three prominent periodicities: 2-7 and 130-200 years for the whole reconstruction and 16-24 years during the 'Little Ice Age' (1520 to 1720). Two points of significant abrupt change in tree rings were found in years of 1530 and 1715, which may indicate the onset of dry and wet conditions during the 'Little Ice Age'. There is an abrupt change around 1965, which may foreshow the beginning of regional prominent warming. [ABSTRACT FROM AUTHOR]

Multiproxies of past environmental conditions, comprising 53 sediment samples analysed for their lithostratigraphic properties (mainly their charcoal, phytoliths and pollen contents) from an AMS 14C-dated sequence of sediments accumulating at Guangfulin, Yangtze delta, are presented. The oldest sediments recovered date to the Lateglacial when a mosaic of mixed (conifer-deciduous) temperate forest and wetland vegetation characterized the study area. The Lateglacial-Holocene transition and much of the early Holocene record to c. 7400 yr BP appears to be missing from the sequence. The earliest evidence possibly representing human activities in the study area (the remains of cereals and indicators of forest) date to c. 7000 yr BP. A large increase in macrocharcoal remains c. 4700 yr BP is a more certain indication of human activities close to the study site, and may indicate the first occupation of what is now the location of a major archaeological excavation at Guangfulin. Technological changes during the Eastern Zhou Dynasty (770-221 BC) may be responsible for an increased abundance of rice (Oryza sp.), and possibly also foxtail or Chinese millet (Setaria italica), detected in the Guangfulin record after c. 2400 yr BP. An abrupt sedimentary change at c. 4000 yr BP may represent a short-lived episode of catchment instability. Aside from this, the sediment record from Guangfulin contains no evidence of dramatic environmental changes that could have led to a major decline in agricultural productivity c. 4000 yr BP, as has been suggested for the lower Yangtze by some researchers, who associate this with the cultural transition from Liangzhu to Maqiao. The findings do, however, add weight to the argument that developments in rice-based agriculture on the Yangtze delta varied both spatially and temporally. [ABSTRACT FROM AUTHOR]

A compilation of early-Holocene terrestrial records from lacustrine sediments, ice cores, peat bog, palaeosols, stalagmites and flood sediments from China indicates that the early-Holocene climate was unstable and characterized by at least one centennial-scale (500-200 years) cooling event between 9.0 and 7.6 ka BP. The cold period recorded in different settings has been previously linked to the 8.2 ka event suggested by δ18Oice from Greenland ice cores, but the differences in time duration and regional climate conditions have been attributed to monsoon systems, inadequate age control and sampling resolution, and complex topography in China. However, our compilation indicates that it is premature to attribute the cold periods recorded at different locations in China simply to the 8.2 ka event, let alone to attribute the cause of those anomalies to a freshening of the North Atlantic Ocean circulation. Whether there was one synchronous event or not in China, where the climate is mainly affected by the monsoons and the westerlies, is open to discussion, because most of the records lack sufficient dating control to define clearly the nature of the cooling event. If a cooling event did occur, more evidence is required in multiple dimensions to characterize the time duration, magnitude and cause of the event, so much work remains to be done. [ABSTRACT FROM AUTHOR]

Rice (Oryza sp.) agriculture sustains vast numbers of people and, despite great advancements made in recent years, questions about its origins and spread throughout Asia remain unanswered. This study uses sedimentary biomarker, stable carbon isotope and palynological analyses to investigate early rice agriculture in the Yangtze delta, a region where rice agriculture emerged at least 7000 years ago. Accelerator mass spectrometer (AMS) 14C dating reveals the age of sedimentary section to be between c. 6000 and 1800 cal. BP. Widespread clearing of forest vegetation c. 2400 cal. BP, is the earliest major human influence detected in the Qingpu record. Following this, rice agriculture probably dominated the Qingpu area. Evidence supporting rice agriculture after c. 2400 cal. BP is provided by increased Poaceae and Cereal-type taxa, which occur with high concentrations of plant wax n-alkanes with a dominant C3 plant origin (C27–C31 with odd/even preference, δ13C -29.8‰ to -36.3‰). Also, high concentrations of a C20 highly branched isoprenoid (HBI) thought to be from epiphytic algae associated with rice agriculture occur after c. 2400 cal. BP. 13C-depleted diploptene (in high concentrations) and 13C-depleted C31 3b-methylhopanes of methanotrophic bacterial origin also occur after c. 2400 cal. BP. The strong methane cycle detected in the trench sediment may have provided an alternative CO2 source for plants and algae associated with rice agriculture. [ABSTRACT FROM AUTHOR]

Aeolian deposits from the Hulun Buir Desert of northeastern China are studied with optically stimulated luminescence dating methods to establish the chronology of dune building phases and climatic changes since the last deglaciation. Our results indicate that wet climate, marked by dune stabilization and soil development in the Hulun Buir Desert, commenced at ∼ 11 ka ago, and this early episode of dune stabilization lasted until ∼ 4.4 ka ago. This optimum climate between ∼ 11 and ∼ 4.4 ka ago is mostly the response to the strengthened monsoon circulation and increased precipitation in the Northern Hemisphere. The environment generally became arid after ∼ 4.4 ka ago, but the dry climate was interrupted by three phases of weak soil development occurring at ∼ 1.8–1.4, ∼ 1.2–1.0 and ∼ 0.84–0.5 ka ago, respectively. Such short events of dune stabilization were associated with the warm and humid climate in historical time. However, the present dune mobilization in the Hulun Buir Desert is mainly the result of poor land-use practices (land cultivation and overgrazing) since about 300 years ago. [ABSTRACT FROM AUTHOR]

High-resolution optically stimulated luminescence (OSL) dating of a terraced loess section in the western margins of the Chinese Loess Plateau provides evidence of continuous and varying accumulation of dust throughout the Holocene. From 12030 to 2500 years ago, the sediment-accumulation rate was approximately 0.2 mm/year. After this time, it increased to approximately 0.8 mm/year, during a historically documented period of agricultural expansion in adjacent areas. From 680 years ago, a further increase in accumu-lation rate, to approximately 3.4 mm/year, is evident. Particle-size analysis indicates that this increase in accumulation rate was associated with anthropogenic addition of sandy sediment, probably for soil improvement. The OSL dating also identifies the period when the terrace was first cut for agricultural use, between 2500 and 2070 years ago. [ABSTRACT FROM AUTHOR]

Evidence of climatic variations and the impact of past farming was identified in a Holocene loess profile near Xi’an in the Guanzhong Basin, China. Detailed studies of the profile indicate that crop cultivation began at 7000 yr BP in the Neolithic and carried on to present in the area. Disturbance of the profile by cultivation has not masked evidence of changes in aeolian dust deposition and bio-pedogenic processes caused by climatic variations. Increased dust deposition indicates that a remarkable aridity phase occurred from 6000 to 5000 yr BP during the Holocene Megathermal (8500–3000 yr BP). The aridity and intensified aeolian dust deposition interrupted the formation of the brown soil developing under a warm-humid subtropical climate during the Megathermal. The palaeosol S0 , normally associated with the Megathermal period, is thus separated into two distinct soils, namely S0 1 and S0 2 . This variability in Megathermal climate may have been widespread across northwestern China. It is also possible that the marked decline in Neolithic culture in the periods of the middle and late Yangshao Culture (6000–5000 yr BP) in the Guanzhong Basin can be attributed to the climatic aridity at the time. [ABSTRACT FROM AUTHOR]