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This paper presents the environmental history and its responses to palaeoclimatic changes since the start of the Holocene in the eastern portion of the desert belt (sand seas and sandy lands) in northern China by comparing the aeolian sandpalaeosol sequences and their palaeoclimatic proxies. The optically stimulated luminescence (OSL) ages of the aeolian sandpalaeosol sedimentary sequences and a series of palaeoenvironmental proxies show that: (1) The large-scale dune landscape currently in the Kubuqi Sand Sea was formed during the Holocene in general; and the palaeosol was generally developed during the period of 4–2 ka, indicating conditions favorable for vegetation growth, soil development, and organic carbon accumulation due to increased precipitation or effective moisture and weakened aeolian activities; the large-scale expansion of dunes in the recent 2 ka is closely linked to human activities. The variable discharge of the Yellow River with diversions for irrigation may have resulted in a more consistent supply of aeolian particles for dune field expansion. (2) The dune landscape of the Hunshandake Sandy Land was likely formed around 12 ka, and before this, the western part of the Hunshandake Sandy Land would have been covered by a single large lake; it was obviously wetter than today in the sandy land during the period of 9.6–3 ka and the palaeosols were developed at the same time. But the aeolian activities have not been completely dormant in this long-lasting wetter epoch; because the Holocene wetter period was likely time-transgressive across the region. (3) The palaeosol of the Hulunbuir Sandy Land began to develop as early as 14.5 ka, probably continuing until the last 2 ka. The palaeosol development of various dune fields in the eastern portion of the desert belt (sand seas and sandy lands) in northern China is spatially heterogeneous, and even the palaeosol development time in different locations within each sandy land is inconsistent. During the middle Holocene (especially the 7.5–3.5 ka), all the sandy lands were stabilized in general and the intensity of aeolian activities was significantly weakened. The number of palaeoenvironmental records in the eastern portion of the desert belt (sand seas and sandy lands) in northern China has increased rapidly in the past decade, but the amount of published data still does not match the vast extent of the dune fields. It does require much more in-depth palaeoenvironmental studies for a full understanding of the relationship between aeolian activities and climate change in northern China. [ABSTRACT FROM AUTHOR]

The rise and fall of ancient cultures and civilizations is a hotly debated topic that has generated disagreements and disputes. In this paper we summarize some case studies on the abandonment of ancient sites, the prosperity and collapse of ancient cultures, and demographic changes, as well as the influence of environment and technology during the prehistoric and historic periods. We then suggest that the dominant influencing factors for the evolution of ancient societies vary by spatial scale. At the local scale, sudden disasters are critical factors leading to the destruction and abandonment of large settlements. On a regional scale, climatic variations (e.g., droughts or cold events lasting for decades or centuries) are important factors that induce the collapse of ancient civilizations and mass migrations, while an enduring and stable optimal climate facilitated the prosperity of ancient civilizations. On a global scale, major technological innovations and their dispersion lasting for centuries and even millennia are major catalysts for population growth and social development. Lastly, we illustrate a possible mechanism under which environmental and technological factors played a critical role in ancient human survival and social evolution on different spatial scales. [ABSTRACT FROM AUTHOR]

The Northern Zhongtiaoshan Fault is a major deep fault at the southern margin of the Yuncheng Basin. There have been few studies on the fault, and the historical earthquakes are few and weak. However, the intensity of activity on the fault should never be underestimated. Through interpretations of aerial images, topography measurements and excavation of trenches, this paper studied the fault distribution, the surface deformation and the activity of the normal fault south of Salt Lake near the city of Yuncheng. By tracing faults in the three trenches, it was found that there had been at least three large paleoseismic events, at 1-3.5, 3.6-4.4 and 7.4-8.8 ka BP. Employing C dating, we determined the same gravel layers in the uplifted side and downthrown side. Making differential Global Positioning System measurements of the vertical difference and topographic profile, we obtained the mean slip rate of the Northern Zhongtiaoshan Fault since 24.7 ka BP (0.75±0.05 mm/a). Using the results of relevant studies, we calculated the possible vertical fault displacement of one earthquake (2.35 m) and obtained the recurrence interval of characteristic earthquakes as 2940-3360 a after dividing the displacement by the mean slip rate. [ABSTRACT FROM AUTHOR]

This paper reviews both the recent and longer-term (Holocene) ecological history of coral reefs in the South China Sea (SCS). (1) Local ecological monitoring since the 1960s shows that the coral reefs in the South China Sea have declined dramatically, reflecting the rapid decrease of living coral cover and the great loss of symbiotic zooxanthellae. Collectively, this has led to a significant decrease of annual CaCO production. Heavy anthropogenic activities and global warming are recognized as major triggers of the observed coral reef degradation. Observations show that the modern coral reefs in the SCS are a source of atmospheric CO in summer. (2) Coral reefs of the SCS have been widely used to reveal longer-term environmental variations, including Holocene high-resolution sea surface temperature (SST) and abrupt climate events, millennial-scale El Niño variations, millennial- and centennial-scale sea level oscillations, strong and cyclic storm activities, East Asian monsoon intensities, variation in seawater pH, and recent seawater pollution. (3) Coral reefs of the southern SCS have experienced repeated episodes of bleaching over the last 200 years due to high SST and intense El Niño events; coral reefs of the northern SCS suffered high levels of mortality during several abrupt winter cold-water bleaching events during the middle Holocene warm period. On average, recovery after the middle Holocene cold-bleaching took 20-30 years; recovery following other middle Holocene environmental stresses took approximately 10-20 years. Such findings have significantly contributed to the understanding of the present ecological pressures faced by the coral reefs in the SCS, the histories of Holocene climate/environment changes, and the long-term models of coral reef responses to various past environmental changes. [ABSTRACT FROM AUTHOR]

The Holocene, the most recent interglacial, provides an important time window for evaluating current global warming and predicting future temperature changes. With the development of new temperature proxies and improvements in climate models, significant progress has been made in understanding Holocene temperature changes. However, a major debate persists about whether global temperatures during the Holocene followed a pattern of gradual warming from the end of the Last Glacial Maximum, which culminated in a temperature maximum in the early to middle Holocene, followed by gradual cooling in the late Holocene (the thermal maximum mode); or whether there was a continuous warming trend that continued to the present day (the continuous warming mode). Significant discrepancies exist between different proxy records as well as between proxy records and models, which have resulted in the "Holocene temperature conundrum" that has challenged paleoclimatologists for the past decade. Here, we summarize the progress made to date in the study of Holocene temperature change via proxy reconstructions, climate model simulations, and paleoclimate data assimilation. We emphasize that the current research has limitations in terms of the multiplicity and seasonality of proxy records, the spatial heterogeneity of temperature records, and the incorporation of feedback processes (e.g., vegetation, cloud-radiation feedback) in climate models. These limitations have hindered a comprehensive understanding of the processes and mechanisms of Holocene temperature changes. To solve the "Holocene temperature conundrum", it is necessary to strengthen theoretical research on climate proxies from the perspective of the underlying processes and mechanisms, elucidate the seasonal response of various temperature proxies, emphasize regional differences in temperature changes, and expand quantitative temperature reconstructions to areas with limited records. However, it is also necessary to improve the simulation performance of complex feedback processes in climate models, reduce simulation errors, and advance the research on data assimilation of Holocene continental temperature records, which may ultimately lead to the optimal integration of paleoclimate records and simulations. [ABSTRACT FROM AUTHOR]

Peatlands are some of the largest carbon reservoirs in terrestrial ecosystems and play a key role in the global carbon cycle. Understanding peatland development, carbon accumulation processes, and the peatland response to varying forcing factors over different temporal and spatial scales helps reveal the underlying processes and general patterns of these ecosystems. To assess the role of climate and local conditions in peatland development, the basal samples from 23 peat cores and three well dated long peat cores were used to explore peatland initiation, lateral expansion, and carbon accumulation rate in the Baijianghe peatland located in the Changbai Mountains, Northeast China. Our results reveal that the Baijianghe peatland was initiated from forest conditions at 7.9 cal. kyr BP and then expanded laterally by paludification. The rapid expansion between 5 and 4 cal. kyr BP likely resulted from high precipitation and gentle topography. The mean carbon accumulation rates of the three long peat cores were 36.3, 39.1 and 48.4 g C m−2 yr−1, respectively, which are higher than rates from the northern peatlands. Both climate and local conditions have exerted an important influence on carbon accumulation rates in the Baijianghe peatland since the middle Holocene. The carbon accumulation patterns between 5 and 1.5 cal. kyr BP were probably linked to local conditions rather than climatic settings, including topography, hydrological conditions, and plant composition. The consistently decreasing carbon accumulation rate values at all locations within the BJH peatland over the last 1.5 cal. kyr BP suggests that climate is the primary control. This study highlights the varying primary controls on the process of peatland development and reveals the important role of local conditions in carbon accumulation. [ABSTRACT FROM AUTHOR]

For a long time, the academic community has known very little about hunter-gatherers in the steppe area of northern China in the mid-Holocene. This article reports on the Ula Usu West site in Siziwangqi Banner, Inner Mongolia, including basic information about the site, animal bones, lithic artifacts and the environmental background. The age of the site is 4.8–4.4 cal. kyr BP, placing it in the Late Neolithic period. Considering integrated evidence from flotation, zooarchaeology, ZooMS analysis and lithic artifacts, the preliminary inference is that the population lived in a hunting-gathering economy. They used lithic tools represented by arrowheads to hunt mainly Antilopinae animals (e.g., Procapra gutturosa). Pollen analysis suggests that the climate was relatively humid, providing advantageous living conditions for the population. The climate evidence is consistent with a warm event at approximately 4.7 kyr BP. A dry-cold event (4.5–4.0 kyr BP) and the gradual expansion of agriculture and breeding might have resulted in the final decline of the population. This article provides new materials for research on the "last" hunter-gatherers in the steppe area of northern China. [ABSTRACT FROM AUTHOR]

Pastoralism is considered a crucial factor in the eventual year-round occupation of high-altitude regions (>3000 m asl) of the Qinghai-Tibetan Plateau, and the northeastern Qinghai-Tibetan Plateau (NE-QTP) was an important corridor for early human occupation. We analyzed fossil fungal spore records for the last 8500 years from a high resolution aeolian section at Langgeri (LGR) on the NE-QTP Thirty-two fungal spore types were identified in the LGR section, including seven coprophilous types. We combined analysis of coprophilous fungal spores, Cyperaceae, Artemisia, and Hippophae pollen, and the charcoal >50 µm fraction to explore the timing and controls of pastoralism on the NE-QTP since the middle Holocene. Pastoralism commenced at LGR shortly before ca. 5.5 ka and gradually increased between ca. 5.5–3.5 ka, but markedly intensified after ca. 2.2 ka, with three periods of growth at ca. 2.1–1.9,1.4–1.2, and 0.6–0 ka, and a decline at ca. 1.1–0.6 ka. The timing of changes in pastoral activity on the NE-QTP based on the coprophilous fungal spore record is supported by regional archeology and historical documents. Technological and political developments, rather than climate change, played key roles in the long-term fluctuations of regional pastoralism on the NE-QTP in the late Holocene. [ABSTRACT FROM AUTHOR]

Topographic/bathymetric conditions of the continental shelf can significantly influence the long-term growth of river deltas. In particular, these conditions constrain the accommodation space for sedimentation in the deltaic areas. In this study, we use a conceptual geometric model to evaluate the role played by this factor, on the basis of the principle of mass conservation. The Ganges-Brahmaputra, Mekong and Nile deltas are examined as three typical examples, in terms of their different original seabed morphologies. The control variate method is applied to eliminate the effect of the difference in model input variables. The results show that, assuming a constant sediment load, the delta growth rate will decrease with time; a higher value of the original seabed slope leads to a lower shoreline progradation rate for the subaerial delta and a higher growth rate for the subaqueous delta. Thus, the original seabed morphology represented by slope is a critical factor affecting the evolution of Holocene large-river deltas. These results explain the interrelationships between sediment load, deltaic plain area, and the original seabed slopes for the 27 large-river deltas worldwide, located in the middle/low latitudes, with different tectonic backgrounds. In the future, the conceptual geometric model may be combined with sediment dynamic modeling to identify more details of the evolution of these deltas. [ABSTRACT FROM AUTHOR]

Since the Last Glacial Maximum (LGM), the global climate has experienced several stages, such as cold and warming events, which provide an ideal model for evaluating climate change in the future. Based on the pollen records in Northeast (NE) China, the vegetation pattern during special periods since the LGM was reconstructed in this work. During the LGM (approximately 18,000 cal yr BP), the steppes expanded rapidly in NE China, and a cold-dry meadow-steppe developed on the Songnen Plain. The Liaohe Plain and the Hulun Buir Plateau were occupied by a steppe-desert, with forest-steppe vegetation grown in the central and southern plains; there were cold-dry coniferous forests and mixed conifer-broadleaf forests in mountainous areas. In the early Holocene (10,000–9,000 cal yr BP), Changbai mountain (CBM) forests thrived in the eastern hilly area and the Sanjiang Plain, while the central region was dominated by steppes, and warm-temperate broadleaf forests developed northward. During the Holocene warm period (approximately 6,000 cal yr BP), CBM forests and cold-temperate coniferous forests developed in the north, while spruce-fir forests developed in the eastern Xiao Hinggan Mountains and the Sanjiang Plain. The distribution centre of deciduous broadleaf forests migrated to the south of the Changbai Mountains and the Liaodong Peninsula. The isolated woodlands increased on the Songnen Plain and the meadow-steppes expanded to the Liaohe Plain. Therefore, the increase in temperature leads to the increase of monsoon precipitation in NE China, which is beneficial to the development of warm-temperate forest vegetation. The increase of summer monsoons and precipitation caused by climate warming may be the main reason for the improved plant load. [ABSTRACT FROM AUTHOR]

The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, paleo-flora and paleofauna records. The results indicate that, during the local Last Glacial Maximum (LLGM) or local Last Permafrost Maximum (LLPMax), the extent of permafrost of China reached 5.3×106−5.4×106 km2, or thrice that of today, but permafrost shrank to only 0.80×106−0.85×106 km2, or 50% that of present, during the local Holocene Megathermal Period (LHMP), or the local Last Permafrost Minimum (LLPMin). On the basis of the dating of periglacial remains and their distributive features, the extent of permafrost in China was delineated for the two periods of LLGM (LLPMax) and LHMP (LLPMin), and the evolution of permafrost in China was divided into seven periods as follows: (1) LLGM in Late Pleistocene (ca. 20000 to 13000−10800 a BP) with extensive evidence for the presence of intensive ice-wedge expansion for outlining its LLPMax extent; (2) A period of dramatically changing climate during the early Holocene (10800 to 8500−7000 a BP) when permafrost remained relatively stable but with a general trend of shrinking areal extent; (3) The LHMP in the Mid-Holocene (8500−7000 to 4000−3000 a BP) when permafrost degraded intensively and extensively, and shrank to the LLPMin; (4) Neoglaciation during the late Holocene (4000−3000 to 1000 a BP, when permafrost again expanded; (5) Medieval Warming Period (MWP) in the late Holocene (1000−500 a BP) when permafrost was in a relative decline; (6) Little Ice Age (LIA) in the late Holocene (500−100 a BP), when permafrost relatively expanded, and; (7) Recent warming (during the 20th century), when permafrost continuously degraded and still is degrading. The paleo-climate, geography and paleopermafrost extents and other features were reconstructed for each of these seven periods. [ABSTRACT FROM AUTHOR]

The inner shelf mud wedge of the East China Sea (ECS) is a high-sedimentation-rate fine-grained sediment unit that has preserved a continuous environmental evolution history since the last deglaciation. We present a high-resolution clay mineralogical study from Core MD06-3040 to semi-quantitatively evaluate terrigenous sediment contributions from various potential provenances throughout the Holocene. The results showed that the clay mineral assemblage is composed of dominant illite (34-49%), moderate smectite (16-41%) and chlorite (15-28%), and minor kaolinite (5-12%). Provenance analysis suggested that most fine-grained terrigenous sediments originated from the Yangtze River, with minor sediments derived from Taiwan island and negligible sediments from nearby Zhejiang and Fujian provinces. Time series variation in the contribution of the Yangtze source fluctuated in the range of 38-80%, whereas that of Taiwan island had a converse variation pattern from ∼10% to ∼55%, and the contribution of Fujian was relatively stable in the range of 7-11% throughout the Holocene. The fluctuations of clay mineral assemblages and variations of clay mineral contributions from different provenances of Core MD06-3040 were controlled by the variability of precipitation in the Yangtze drainage associated with periodic fluctuations in the East Asian monsoonal circulation. [ABSTRACT FROM AUTHOR]

The emergence of complex society is a milestone in the history of human society evolution. China is one of the few regions in the world where the earliest complex society appeared; however, its driving mechanisms remain unresolved. On the base of available evidence from both archaeology and Holocene climate, in combination with agency theory, this study attempts to address the driving mechanisms for the simultaneous emergence of complex societies in multiple areas of China around 5.5 cal ka BP. It is hypothesized that three factors, including climate change, population growth, and circumscription, jointly act and cause regional population-resource imbalance and trigger inter-group conflicts and wars. Such competitions provide the opportunity for some power-pursuing agents to break the restriction of social leveling mechanism and to become the centralized decision-making leaders, which further lead to the emergence of incipient large-scale complex societies. Increase in extreme climate events during 6.0-5.0 cal ka BP cooling period causes frequent occurrence of resource stress and increase in the frequency of inter-group competitions, which creates conditions for the legitimation, institutionalization, and persistence of centralized leadership, and finally leads to the formation of persistent institutionalized inequity. Our research result can explain not only the process and mechanism of complex society formation, but also two phenomena which cannot be reasonably explained by previous theories, that are, why the earliest complex societies in China emerge around 5.5 cal ka BP, and why they appear simultaneously in multiple regions. [ABSTRACT FROM AUTHOR]

Understanding the response of ecosystems to past climate is critical for evaluating the impacts of future climate changes. A large-scale abrupt shift of vegetation in response to the Holocene gradual climate changes has been well documented for the Sahara-Sahel ecosystem. Whether such a non-linear response is of universal significance remains to be further addressed. Here, we examine the vegetation-climate relationships in central Asia based on a compilation of 38 high-quality pollen records. The results show that the Holocene vegetation experienced two major abrupt shifts, one in the early Holocene (Shift I, establishing shift) and another in the late Holocene (Shift II, collapsing shift), while the mid-Holocene vegetation remained rather stable. The timings of these shifts in different regions are asynchronous, which are not readily linkable with any known abrupt climate shifts, but are highly correlated with the local rainfalls. These new findings suggest that the observed vegetation shifts are attributable to the threshold effects of the orbital-induced gradual climate changes. During the early Holocene, the orbital-induced precipitation increase would have first reached the threshold for vegetation 'establishment' for moister areas, but significantly later for drier areas. In contrast, the orbital-induced precipitation decrease during the late Holocene would have first reached the threshold, and led to the vegetation 'collapse' for drier areas, but delayed for moister areas. The well-known 4.2 kyr BP drought event and human intervention would have also helped the vegetation collapses at some sites. These interpretations are strongly supported by our surface pollen-climate analyses and ecosystem simulations. These results also imply that future climate changes may cause abrupt changes in the dry ecosystem once the threshold is reached. [ABSTRACT FROM AUTHOR]

It is generally recognized that millet agriculture originated in northern China. However, the domestication process of foxtail millet ( Setaria italica) and broomcorn millet ( Panicum miliaceum) is still poorly understood. Based on statistical and morphological analyses of ancient millet starch grains, a tangible hypothesis has been proposed for the long-term domestication of green foxtail millet ( S. viridis). However, the hypothesis requires validation by evidence from more regions and more archaeological finds. The West Liaohe region is one of the earliest regions of millet cultivation. Here, we report ancient starch grains recovered from 12 stone grinding tools from eight sites of the Xiaohexi culture (before 8.5 ka BP), Xinglongwa culture (8.2-7.4 ka BP), Zhaobaogou culture (7.0-6.4 ka BP), and Hongshan culture (6.5-5.0 ka BP) in the West Liaohe region of China. Our results indicate that the proportion of millet starch grains with wrinkled surfaces and rough edges, which are diagnostic of wild millet grasses, decreased from 13.0% to 3.4% from the Xiaohexi culture to the Hongshan culture. Millet starch grains measuring >16.8 μm, a size class recorded only in domesticated foxtail millet, increased from 55.0% to 62.1%. These millet data imply that the process of millet domestication in the West Liaohe region began in the Xiaohexi period and continued up to the Hongshan period. [ABSTRACT FROM AUTHOR]

Many lakes exist in southeastern Badain Jaran Desert and its hinterland, including 110 perennial lakes and some seasonal or extinct lakes. Geomorphological, sedimentological, and bioglyph evidence obtained from field investigations on Badain Jaran Desert lake group, alongside measurements and dating performed on lake relic, prove that these lakes expanded while the climate was relatively wet during early and middle Holocene. The dating results suggest that the pan-lake period of the Badain Jaran Desert began at 10 cal kyr BP, before which the limnic peat period occurred (11-10 cal kyr BP). Many lakes reached their maximal water-level during 8.6-6.3 cal kyr BP and retreated or dried up in the late Holocene (about 3.5-0 cal kyr BP). During that period, the precipitation at Badain Jaran Desert may have reached 200 mm yr?1 for 7.7-5.3 cal kyr BP, inferred from both the age and precipitation rate of calcareous root tubes. The water balance calculation shows that wetter and warmer climate and the increase of underground water recharge were key factors in maintaining and developing the lake group at both centennial and millennial time scales. Furthermore, lake surface expansion and the increasing fresh water availability set the background for the prosperous prehistoric culture. [ABSTRACT FROM AUTHOR]

Sediment pollen samples from the Huola Basin in the northern sector of northeast China, and surface pollen samples from its environs, were analyzed to reconstruct accurately the historical response of vegetation to climate change since 9100 cal yr BP. Pollen analysis of the Huola Section indicates that vegetation experienced a transformation from early-mid Holocene warm-cold mixed vegetation to late Holocene cold-temperate vegetation. From 9100 to 6000 cal yr BP, the study area was warmer and moister than at present, developing Corylus, Carpinus, Pinus, Picea, Betula and Larix-dominated forests. Two cooling events at 6000-5000 and 3500-2500 cal yr BP led to a decrease in Corylus, Carpinus and other warmth-loving vegetation, whereas cold temperate forests composed of Larix and Betula expanded. After 2500 cal yr BP, Larix and Betula dominated cold-temperate vegetated landscapes. The Holocene warm period in NE China (9100-6000 cal yr BP) suggests that such warming could have resulted in a strengthening of the influence from East Asian Summer Monsoon on northernmost NE China and would have benefited the development of warm-temperate forest vegetation and an improved plant load, which also provides the similarity model for the possible global warming in the future. [ABSTRACT FROM AUTHOR]

We present lipid biomarker records of two cores (ZY1 and ZY3) from the central South Yellow Sea mud area to investigate the changes in sources and transport processes of the sedimentary organic matter (OM) throughout the Holocene. Based on the analysis of marine biomarker content (∑PB (Phytoplankton Biomarker, total content of brassicasterol, dinosterol and C-alkenones) and crenarchaeol), and terrestrial biomarkers (∑ n-alkanols and brGDGTs) as well as TMBR′ and BIT index values, the marine organic matter (MOM) and terrestrial organic matter (TOM) deposition history was reconstructed. Changes in TOM and MOM were related to variations in land vegetation density and marine productivity, as well as transport processes dominated by the oceanic circulation system. The marine biomarker contents from the South Yellow Sea have generally increased throughout the Holocene, indicating that the increased MOM contents were mainly controlled by the strengthening of the circulation system. The terrestrial biomarkers, on the other hand, were more variable, indicating more complex influence of TOM burial in the Yellow Sea. During the Early Holocene (7200-6000 cal yr BP), the moderate TOM input revealed by the terrestrial proxy records may result from abundant land source supply by strong river transport despite the lack of transport via circulation system. The Mid-Holocene (6000-3000 cal yr BP) was characterized by decreased terrestrial biomarker contents. The balance between the decrease in land source supply and increase of transportation by the current system of the TOM resulted in the lower but stable contents of TOM. During the Late Holocene (3000 cal yr BP to present), the TOM deposition in the South Yellow Sea increased as the current system was further enhanced and thus transported more TOM to the central South Yellow Sea, although the land supply of TOM was further reduced. [ABSTRACT FROM AUTHOR]

Significant uncertainties remain regarding the temporal evolution of natural vegetation during the Quaternary, and drivers of past vegetation change, on the Chinese Loess Plateau (CLP). This study presents analyses of total organic carbon isotopic composition (TOC) and n-alkane ratios (C31/C27) from the Lingtai loess-palaeosol sequence on the central CLP over the last 450 kyr. The results demonstrate that the vegetation in this region comprised a mix of C and C plants of herb and woody growth-form. C plants dominated for most of the last 450 kyr, but this did not lead to extensive forest. C woody plants were more abundant in MIS9 (S3 period) and MIS5 (S1 period) during warm and humid climate conditions. Herbs increased in the region since 130 kyr, possibly as a result of increased aridity. On the orbital timescales, there was a reduction of C herbal plants in MIS11 (S4) than in MIS12 (L5), and in Holocene than in the last glacial period. Our isotope and n-alkane proxy records are in agreement with Artemisia pollen changes in the region, which is/was the dominant species in this area and varying due to different heat and water conditions between glacial and interglacial periods. Though the climate in MIS1 (S0) was similar to that in MIS11 (S4), a significant increase in woody plants during the Holocene suggests the impact of human activities and ecological effects of changes in fire activity. [ABSTRACT FROM AUTHOR]

Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental changes. As an important ecological factor, the occurrence of fire is affected by vegetation cover, and fire can feed back into both vegetation and climatic change. The causes of fire events are diverse; and can include volcanic eruptions. The amount of charcoal in sediment sequences is related to the frequency and intensity of fire, and hence under good preservation conditions fire history can be reconstructed from fossil charcoal abundance. Until now, little research on the role of fire has been carried out in northeastern China. In this study, through research on charcoal and tephra shards from Gushantun and Hanlongwan, Holocene vegetation change in relation to fire and volcanic events in Jilin, Northeastern China, was investigated. Where tephra shards are present in Gushantun it is associated with low level of both conifers and broadleaved trees, and is also associated with a pronounced charcoal peak. This suggests forest cover was greatly reduced from a fire caused by an eruption of the Tianchi volcano. We also detected one tephra layer in Hanlongwan, which also has the almost same depth with low level forest pollen values and one charcoal peak. This was caused probably by an eruption of the Jinlongdingzi volcano. [ABSTRACT FROM AUTHOR]

The internal genetic clock of semelparous mast-flowering bamboo species creates gregarious regions of flowering and death, thus leading to fuel-load accumulation that potentially promotes fire (Fire-Cycle Hypothesis). Higher abundance of bamboo could be expected to provide greater fuel loads after flowering. Here, we investigated the possible link between bamboo dominance and fire occurrence. As the main food source for the giant panda in the Qinling Mountains of China, Bashania fargesii (Farges Canebrake) and Fargesia qinlingensis (Arrow Bamboo) dominate lower (1000-1900 m) and higher elevations (1800-2700 m), respectively. Four soil profiles (elevation ranging from 1240 to 2170 m) in areas of known recent bamboo flowering events (∼1980) and adjacent non-flowering sites were assessed for phytoliths and charcoal. Characteristic phytoliths were chosen to describe bamboo dynamics, and charcoal particles were extracted from the soil to reconstruct fire history. Carbon 14 dating of soil charcoal samples was conducted using an accelerator mass spectrometry technique. In addition, we chose two depths (28-52 and 90-100 cm) in one Bashania profile ( B. fargesii forest) and one Fargesia profile ( F. qinlingensis forest) for phytolith dating. Our findings indicate that bamboo has been a dominant component of these ecosystems almost for the entire profile; some 6400 yrs for Bashania and ca. 10000 yrs for the Fargesia. It is also clear from the charcoal and phytolith data that bamboo abundance and recent mast flowering were significantly related to fire occurrence for lower elevation Bashania while the higher elevation Fargesia was not. One of the four profiles had chronological charcoal records throughout and the oldest charcoal aged was ∼1410 yr BP, suggesting an anthropogenic origin. The mixing of phytolith and charcoal made it unrealistic to describe temporal dynamics of bamboo and fire events, and thus our interpretation is cognizant of the dating discrepancies and conservative (less-speculative). Due to the long history of bamboo and much shorter history of fire within the profile, our data lend little evidence to the Fire-Cycle Hypothesis. [ABSTRACT FROM AUTHOR]

We present the major results from studies of fire history over the last 11000 years (Holocene) in southern Sweden, on the basis of palaeoecological analyses of peat sequences from three small peat bogs. The main objective is to emphasize the value of multiple, continuous sedimentary records of macroscopic charcoal (macro-C) for the reconstruction of local to regional past changes in fire regimes, the importance of multi-proxy studies, and the advantage of model-based estimates of plant cover from pollen data to assess the role of tree composition and human impact in fire history. The chronologies at the three study sites are based on a large number of C dates from terrestrial plant remains and age-depth models are achieved using Bayesian statistics. Fire history is inferred from continuous records of macro-C and microscopic charcoal counts on pollen slides. The Landscape Reconstruction Algorithm (LRA) for pollen-based quantitative reconstruction of local vegetation cover is applied on the three pollen records for plant cover reconstruction over the entire Holocene. The results are as follows: (1) the long-term trends in fire regimes are similar between sites, i.e., frequent fires during the early Holocene until ca. 9 ka BP, low fire frequency during the mid-Holocene, and higher fire frequency from ca. 2.5 ka BP; (2) this broad trend agrees with the overall fire history of northwestern and western Europe north of the Mediterranean area, and is due to climate forcing in the early and mid-Holocene, and to anthropogenic land-use in the late Holocene; (3) the LRA estimates of plant cover at the three sites demonstrate that the relative abundance of pine played a primordial role in the early and mid-Holocene fire history; and (4) the between-site differences in the charcoal records and inferred fire history are due to local factors (i.e., relative abundance of pine, geomorphological setting, and anthropogenic land-use) and taphonomy of charcoal deposition in the small peat bogs. It is shown that continuous macro-C records are most useful to disentangle local from regional-subcontinental fire history, and climate-induced from human-induced fire regimes, and that pollen-based LRA estimates of local plant cover are more adequate than pollen percentages for the assessment of the role of plant composition on fire history. [ABSTRACT FROM AUTHOR]

Based on optimal foraging theory, prey animals from the Shuidonggou Locality 12 (SDG12) are divided into three types according to body size and defense traits: high-ranked large game, low-ranked slow small game, and low-ranked fast small game. Application of the Reciprocal of Simpson's Index to the three types of animals from SDG12 yields a relatively high level of evenness, which implies a broader meat diet of the SDG12 hominids. Compared to values of taxonomic evenness from Mediterranean sites, it is suggested that this dietary expansion probably resulted from the occurrence of the Broad Spectrum Revolution rather than from climatic changes in the Shuidonggou area. Comparative studies between the Natufian phases in Hayonim Cave and the SDG12 validate this argument. [ABSTRACT FROM AUTHOR]

The Gongga Mountain is the largest area of modern glaciation in the Hengduan Mountains and, with a summit elevation of 7556 m, is the highest mountain on the eastern margin of the Tibetan Plateau. During the Quaternary glacial-interglacial cycles the Gongga Mountain was extensively and repeatedly glaciated, and glacial landforms and outwash deposits from multiple glaciations are well-preserved in valleys, in basins, and on piedmonts. To constrain the glacial chronology of the eastern slope of Gongga Mountain, sample sites were selected based on the distribution and weathering of glacial tills, relationships among glacial deposits, and soil development on moraines. Dating of the tills and glaciofluvial deposits was undertaken with electron spin resonance (ESR) and optically stimulated luminescence (OSL). The ages of the glacial deposits can be divided into four clusters: 2.2±0.5, 11.9±0.6, 35.9±2.7-58.0±6.3 and 119.2±15.9-194.2±32.8 ka. Five glacial advances in this region have been identified, which are equivalent in age to the Little Ice Age (LIA), Neoglaciation, marine oxygen isotope stage (MIS) 2, mid-MIS3, and MIS6. The largest local last glacial maximum (LGM) occurred on Gongga Mountain during mid-MIS3, characterized by a cold-humid climate, rather than the global Last Glacial Maximum (LGM) of MIS2. The Gongga, Nanmenguangou (NMGG) and Yajiageng Glaciations occurred during the late part of the last glacial cycle, the middle of the last glacial cycle and the penultimate glacial cycle, respectively. On the basis of geomorphological, sedimentological, and compositional characteristics, landforms of the Moxi Platform and terraces can be grouped by facies and geochronology. In combination with the dating results, this analysis indicates the basal part of the Moxi Platform between Xinxin and the Moxi Hotel is correlative with the till of the Nanguanmen Glaciation (mid-MIS3). This basal unit has occasional lenses of glaciofluvial sandy gravel and lacustrine sediments. The remainder of the Moxi Platform and the terraces beside the platform are glaciofluvial deposits occasionally mixed with debris flow deposits and range in age from MIS3 to Holocene. [ABSTRACT FROM AUTHOR]

Changes in the vegetation and climate of the westerly-dominated areas in Central Asia during the Holocene were interpreted using pollen-assemblages and charcoal data from a 300-cm-long sediment core of the Sayram Lake, northern Xinjiang. Accele-rator Mass Spectrometry (AMS) radiocarbon dating methods were applied to bulk organic matter of the samples. Artemisia spp./Chenopodiaceae ratios and results from principal component analysis were used to infer that the lake basin was dominated by desert vegetation before ca. 9.6 cal. ka BP, which suggests a warm and dry climate in the early Holocene. Desert steppe/steppe expanded during 9.6-5.5 cal. ka BP, indicating a remarkable increase both in the precipitation and temperature during the mid-Holocene. Desert vegetation dominated between 6.5 and 5.5 cal. ka BP, marking an extreme warmer and drier interval. The steppe/meadow steppe recovered, and temperatures decreased from 5.5 cal. ka BP in the late Holocene, as indicated by the increased abundance of Artemisia and the development of meadows. Holocene temperatures and moisture variations in the Sayram Lake areas were similar to those of adjacent areas. This consistency implies that solar radiation was the main driving factor for regional temperature changes, and that the effect of temperature variations was significant on regional changes in humidity. The evolution of climate and environment in the Sayram Lake areas, which were characterized as dry in the early Holocene and relatively humid in the middle-late Holocene, are clearly different from those in monsoonal areas. Dry conditions in the early Holocene in the Sayram Lake areas were closely related to decreased water vapor advection. These conditions were a result of reduced westerly wind speeds and less evaporation upstream, which in turn were caused by seasonal changes in solar radiation superimposed by strong evaporation following warming and drying local climate. [ABSTRACT FROM AUTHOR]

Transported by wind and water, the relatively old sediments can deposit in the terminal lake of an inland drainage basin. The reworking effect can affect the lake sediments C dating and explanations for proxies. The Zhuye Lake is the terminal lake of the Shiyang River Basin. Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns. And then, some radiocarbon dates were inverted for some Late Pleistocene sections. Whether this phenomenon is related with the reworking effect? The pollen concentrates C dating can avoid the reservoir effect, which is an ideal method for studying the reworking effect. In this study, we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin. Based on the C dates comparison between the pollen concentrates, organic matter, and shells, the pollen concentrates dates are relatively older than other dating materials. Based on the result, the reworking effect worked in the Zhuye Lake Basin during the Holocene; however, in different locations of the lake basin the reworking effects were in different levels. Furthermore, the Holocene lacustrine deposits were formed mostly during the early and middle Holocene. This study provided clues for reworking effect studies of other lakes in arid China. [ABSTRACT FROM AUTHOR]

Three cores (ZY-1, ZY-2 and ZY-3) retrieved from the Central Yellow Sea mud (CYSM) were analyzed in sensitive grain size and AMS C dating to reconstruct the history of the East Asian Winter Monsoon (EAWM) since the Middle Holocene in the study area. The results show that these data provide a continuous history of the EAWM over the past 7.2 ka and that the EAWM can be divided into three periods: strong and highly fluctuating during 7.2-4.2 ka BP; moderate and relatively stable during 4.2-1.8 ka BP; and weakened during 1.8-0 ka BP. Compared with the East Asian Summer Monsoon (EASM) recorded in the previous studies, the evolutionary history of the EAWM broadly follows the orbital-derived winter insolation with a similar long-term step-decreased trend as the EASM. At the centennial scale, however, the EAWM intensified events correlate well with the EASM weakened events and the North Atlantic climatic variations (Bond events 0 to 5) within the dating error, most likely forced by the reduction of solar irradiance through changes in the oceanic-atmospheric circulation patterns. [ABSTRACT FROM AUTHOR]