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There are few studies on the climate and glacial scale in the mountains east of the Qinghai–Tibet Plateau. So, we used glacial features to determine the range of the area's paleoglaciers and the equilibrium line altitude (ELA) of theGlA modern and paleoglaciers in the Tianchi area of the Changbai Mountains. Then, the GlaRe toolbox 2015 () was used to reconstruct the surface of the paleoglaciers. The probable air temperature during the glacial advances of the LGM was calculated by applying the P-T and LR models. The results showed the following: (1) the change in ELA is 950 m in the Tianchi area of the Changbai Mountains; (2) glacial coverage in the Tianchi area of the Changbai Mountains during the LGM period was ~27.05 km2 and the glacial volume was ~9.94 km3; and (3) the mean temperature in the Tianchi area of the Changbai Mountains during the LGM was 6.6–9.0 °C lower than today's, and was the principal factor controlling the growth of glaciers. There is a difference in the climate change in monsoon-influenced mountains during the LGM, and this difference may be related to the precipitation in the mountains. [ABSTRACT FROM AUTHOR]

Helianthemum songaricum and H. ordosicum are two shrubs disjunctively distributed in Central Asia and northwestern China. For conservation purposes, we used genotyping by sequencing (GBS) to investigate the genetic diversity and genetic structure of their populations. Based on the GBS data, H. songaricum populations showed considerable genetic differences from H. ordosicum populations. Helianthemum songaricum populations also showed a stronger population genetic structure within the isolated valleys in the Tianshan Mountains than was seen in previous studies. We speculated that the two species may represent two cotemporal migration events between the Middle East and Central Asia/Ordos Plateau since the early Pliocene. Due to the intense uplift of the Tianshan Mountains in the late Pliocene, populations of H. songaricum were isolated in different valleys. Subsequently, the cold glacial climate during the Pleistocene intensified the in situ intraspecific differentiation of the species. Based on our single nucleotide polymorphism data, we propose habitat damage by anthropological activities, where the two species inhabit should be urgently prohibited by executive management. In addition, a nursery for germplasm resources should be urgently set up to culture adequate progenies for the purpose of expanding the populations. [ABSTRACT FROM AUTHOR]

Effective moisture (EM) distribution in the Indian summer monsoon (ISM) region is strongly related to regional topography. An understanding of climate change and the interactions between climate variables can help predict future climate variations. Here, we reconstruct a stack EM record for Southwest China over the past 90 kyr using environmental magnetism in lake sediment. The EM in Southwest China at the orbital scale was closely linked to precession‐induced change in North Hemisphere solar insolation, as well as the ISM variability. However, at the glacial‐interglacial scale, it was decoupled with ISM intensity, being wetter during glacial periods (weakened ISM) and drier during interglacial periods (enhanced ISM). Combined with modern meteorological observations, we suggest that the topographical barrier effect and temperature induced dryness are responsible for the decoupling between ISM intensity and EM. The terrestrial topography and temperature strongly influence EM distribution by altering the dynamics of onshore airflow and evapotranspiration. Plain Language Summary: Effective moisture (EM) directly affects hydrological cycle and wider‐scale socio‐economic development. Reconstruction of prehistoric EM levels is essential for deeper understanding of the global climate system, developing climate models and improving prediction of future climate variations. Here, we reconstruct a high‐resolution EM record over the past ∼90,000 years from lake sediments in Tengchong, Yunnan province, Southwest China. We found that the variation of precession (shifts in the rotational axis of the Earth) and solar insolation are the key contributors to the EM variability at the orbital scale. Unusually, a wetter climate during the glacial period and relatively drier interglacial periods were observed in our records, which is opposite to those found in previous studies (arid glacial and humid interglacial) in monsoon regions, indicating a decoupling pattern between monsoon intensity and EM in study region. Based on a comprehensive analysis of the modern meteorological observations, we conclude that the topography and temperature exert a considerable role in modulating EM distribution and response to the decoupling pattern. Key Points: The long‐term effective moisture (EM) record in Southwest China since ∼90 kyr was reconstructedThe EM variability at the orbital scale in terrestrial Indian summer monsoon region is primarily dominated by precessionThe topographic barrier and temperature induced aridification contribute to the decoupling of monsoon intensity and EM [ABSTRACT FROM AUTHOR]

Species' phylogeographic patterns reflect the interplay between landscape features, climatic forces, and evolutionary processes. Here, we used two chloroplast DNA (cpDNA) markers (trnL and trnL - F) to explore the role of stepped geomorphology in shaping the phylogeographic structure of Toxicodendron vernicifluum , an economically important tree species widely distributed in East Asia. The range-wide pattern of sequence variation was analyzed based on a dataset including 357 individuals from China, together with published sequences of 92 individuals mainly from Japan and South Korea. We identified five chloroplast haplotypes based on seven substitutions across the 717-bp alignment. A clear east-west phylogeographic break was recovered according to the stepped landforms of mainland China. The wild trees of the western clade were found to be geographically restricted to the "middle step", which is characterized by high mountains and plateaus, while those of the eastern clade were confined to the "low step", which is mainly made up of hills and plains. The two major clades were estimated to have diverged during the Early Pleistocene, suggesting that the cool glacial climate may have caused the ancestral population to retreat to at least two glacial refugia, leading to allopatric divergence in response to long-term geographic isolation. Migration vector analyses based on the outputs of ecological niche models (ENMs) supported a gradual range expansion since the Last Interglacial. Mountain ranges in western China and the East China Sea land bridge were inferred to be dispersal corridors in the western and eastern distributions of T. vernicifluum , respectively. Overall, our study provides solid evidence for the role of stepped geomorphology in shaping the phylogeographic patterns of T. vernicifluum. The resulting east-west genetic discontinuities could persist for a long time, and could occur at a much larger scale than previously reported, extending from subtropical (e.g., the Xuefeng Mountain) to warm-temperate China (e.g., the Taihang Mountain). [ABSTRACT FROM AUTHOR]

Quaternary palynology in the Tibetan Plateau (TP) was initiated in the 1960s to meet the needs of economic development in western China. Pollen analysis was conducted for the first time on a 200-m long core of Quaternary lacustrine sediments taken from the main body of the TP in order to study pollen assemblages as well as vegetation and climate changes of glacial (cold)/interglacial (warm) periods. Pollen analysis of alpine snow and ice began at the first scientific expedition to the TP in the 1970s. After the 1980s, a series of international collaborative programs were carried out under Sino-French, Sino-German, Sino-Australian, and Sino-American cooperation, marking the integration of Chinese Quaternary palynology society with the international community. New methods for Quaternary palynology were gradually promoted and applied, changing the vegetational and climatic interpretation of Quaternary palynology from qualitative to quantitative. Since the 1990s, many palynologists have carried out extensive Quaternary palynological studies on fossil pollen sites of more than 60 lakes/sections and alpine glaciers in the TP to discuss the spatiotemporal vegetation changes and climatic and environmental evolution of the TP since the Pleistocene. Over the past half-century, Quaternary palynology in the TP has contributed to the establishment of the Chinese Quaternary pollen database and the study of vegetation and climate evolution since the Last Glacial Maximum (LGM) in the TP. Currently available pollen records revealed the spatial and temporal distribution of vegetation in the TP since the LGM, exhibiting expansions and shrinkages of forest, meadow, grassland and desert in different periods such as the LGM, the last deglaciation, and Holocene optimum period. The paleomonsoon reflected by paleovegetation since the LGM has undergone the changes of weak-strengthening-strong-weakening but still active-shrinking, which is mainly affected by solar insolation. [ABSTRACT FROM AUTHOR]

Although difficult to resolve, seasonality is an important element in considering paleoenvironmental records and simulated results, and it is therefore critical to address this shortcoming in order to develop more accurate reconstructions of past climate. In this study, climatic proxies with seasonal implications (magnetic susceptibility and mean grain size) are analyzed for several high‐resolution loess sections from mid‐latitude Asia using the Ensemble Empirical Mode Decomposition (EEMD) to detect their response to millennial‐scale oscillations during the last glaciation. In so doing, we are capable to estimate the amplitude and relative contribution of the reconstructed climate components. Combined with an analysis of modern processes, magnetic susceptibility (χ) can be interpreted as representing summer and spring precipitation, while mean grain size (Mz) can be interpreted as representing spring and summer dust activity in the Chinese Loess Plateau (CLP) and southern central Asia (SCA), respectively. Our results show that the spring and summer signals are clearly correlated with Heinrich events, but that the spring signal is more prominent than the summer signal during Dansgaard‐Oeschger (D‐O) oscillations of the last glacial. These results are consistent with modeled simulations. It is proposed that weakening or complete shutdown of AMOC influences the response of seasonal signals to abrupt climate events. The study highlights the need for further high‐resolution climate proxies with robust seasonality indicators in order to develop a deeper understanding of the response of mid‐latitude Asia to rapid climate events. Key Points: The climate over mid‐latitude Asia presented seasonal response to abrupt climate events during the last glacialSpring climate is more sensitive to millennial‐scale abrupt events than summerThe weakening and closing of the Atlantic meridional overturning circulation influence the seasonal response [ABSTRACT FROM AUTHOR]

Detailed organic carbon isotope (δ13Corg) measurements were conducted on two peat sequences recovered from the north bank of the Yangtze River, East China. Seven radiocarbon dates provided firm age control of this δ13Corg record and reveal palaeoclimatic changes since the Late Glacial period. The results show that the Holocene Megathermal Maximum occurred between 8385 and 7040 cal. yr BP. The Late Glacial climate was generally cold but fluctuated frequently between 12940 and 11815 cal. yr BP. The Older Dryas (from 12940 to 12810 cal. yr BP) and the Younger Dryas (from 12645 to 12170 cal. yr BP) were characterised by cold climate conditions. In contrast, 12810 to 12645 cal. yr BP (corresponding to the Allerød Warm Period) and 12170 to 11815 cal. yr BP (corresponding to a rapid warming period after the Younger Dryas, marking the beginning of the Holocene) were relatively warm phases. In contrast to other high-resolution records, it shows that the δ13Corg records of our study peats are largely controlled by a common forcing mechanism of solar insolation changes in the Northern Hemisphere, and exhibit similar variability to δ18O records obtained from stalagmites and GISP2 during the Late Glacial and early-mid Holocene. [ABSTRACT FROM AUTHOR]

Studies on long‐chain n‐alkan‐2‐ones from lake sediments remain sparse. In this study, we present an n‐alkan‐2‐one record from Qionghai Lake, southwest China, to assess the paleoclimate significance of variations in their compositions. A homologous series of n‐alkan‐2‐ones ranging from C21 to C35 were identified, with maximum concentrations of the C29 or C31 chain lengths and a strong odd‐over‐even predominance. This type of n‐alkan‐2‐one is considered to derive mainly from microbial oxidation of the corresponding n‐alkanes, and partial inputs from plants. The n‐alkan‐2‐one‐derived average chain length (ACL) and carbon preference index (CPI) values changed significantly over the past 28k cal a bp, consistent with the sediment grain size and n‐alkane proxies from the same core. Generally, the high CPI27‐33‐ket and low ACL27‐33‐ket values indicated cold and dry climates such as for the Last Glacial Maximum (23.2–19.7k cal a bp), Heinrich 1 event (17.6–15.6k cal a bp) and Younger Dryas (12.8–11.6k cal a bp), but low CPI27‐33‐ket and high ACL27‐33‐ket values denoted a warm and humid Holocene Climatic Optimum (7.0–4.3k cal a bp). Therefore, n‐alkan‐2‐ones have great paleoclimatic potential and can be applied together with other biomarkers to reconstruct a reliable paleoclimate record in lake sediments. [ABSTRACT FROM AUTHOR]

Palynological records were selected from the profiles of three research sites in the mountainous interior of southern China (Dajiuhu at Shennongjia in the western part of Hubei Province, Dahu in the Nanling Mountains, and Gantang in the northern part of Fujian Province). It can be inferred that the forest vegetation growing in the south of the Qinling Mountains-Huaihe River was luxuriant during the late glaciation. The species succession with ecological significance in palaeoflora ( Abies sp., Fagus sp. and Alnus sp.) revealed that there was a certain amount of precipitation and effective humidity in the mountain lands between Qinling Mountains-Huaihe River and Nanling Mountains. This ecological environment favored the zonal distribution of mountainous forest vegetation. The late glacial maximum featured a cold, wet climate that completely differed from the cold-dry climate on the Loess Plateau, and on the steppe and desert steppe of the Qinghai-Tibet Plateau. Besides being influenced by the predominant factors driving the Northern Hemisphere climate, the cold-wet climate feature of the mountainous interior of southern China was closely associated with some geographical factors such as the latitudinal position, proximity to the ocean, and the topography and landforms. [ABSTRACT FROM AUTHOR]

Well-preserved Late Glacial moraines in the Barenduo and Yuqiongqu valleys on the eastern slope of the Samdainkangsang Peak present an opportunity to reconstruct glacier extents and examine the character of the climate during the Late Glacial stage in the Nyaiqentanggulha Mountains. This study employs a coupled mass-balance and ice-flow model to reconstruct the glacier extents in the two valleys and assess the magnitudes of temperature and precipitation change during the Late Glacial period. Model results indicate that during the Late Glacial, the Barenduo valley contained an ice volume of 1.67×108 m3, with the equilibrium-line altitude (ELA) being ~5500 m asl; and the Yuqiongqu valley had an ice volume of 5.56×108 m3, with the ELA being ~5470 m asl. A climate scenario, temperature depression of 2.6-2.8°C and 60-70%, percent of modern (1981-2010) precipitation, can sustain both of the Late Glacial glacier extents in the two valleys. A 50% increase or decrease from modern precipitation would have been coupled with the respective Late Glacial temperature depressions of 1.6 and 3.0°C in the Barenduo valley, and 2.1 and 2.8°C in the Yuqiongqu valley. [ABSTRACT FROM AUTHOR]

Using simulations performed by all available climate models participating in the latest Paleoclimate Modelling Intercomparison Project (PMIP) phase 3 (PMIP3), we revisited the climate over China and the East Asian monsoon during the last glacial maximum (LGM; 21,000 years ago). Similar to previous results obtained from the PMIP phases 1 and 2 (PMIP1/2) models, all nine models reproduced colder than the pre-industrial annual and seasonal temperatures over China during the LGM and underestimated the annual cooling as evidenced by proxy data. The LGM annual and seasonal precipitation and evaporation over China consistently decreased in the models, whereas the very small LGM change in net precipitation (precipitation minus evaporation) differed among models. The annual net precipitation change during the LGM was broadly consistent with reconstructed moisture conditions over most parts of China, especially over the western Tibetan Plateau where the PMIP1/2 models disagreed with the proxy data. Moreover, the LGM winter monsoon circulation weakened (strengthened) over the East Asian continent in four (one) of five models; the summer monsoon circulation generally weakened in two models, whereas it weakened north and strengthened south of about 30°N over East Asia in three models. The spatial patterns of the LGM change in East Asian winter and summer monsoons in the PMIP3 models differed somewhat from those in the PMIP1/2 simulations. [ABSTRACT FROM AUTHOR]

We present a new 230 Th-dated absolute chronology of Asian summer monsoon (ASM) variability from 113.5 to 86.6 kyr BP (before 1950 AD). This integrated multidecadally resolved record, based on 1435 oxygen isotope data and 46 230 Th dates with 2-sigma errors as low as ±0.3 kyr from three stalagmites collected in Sanxing Cave, southwestern China, can be a new reference for calibrating paleoclimate proxy sequences. The Sanxing δ 18 O record follows the 23 kyr precessional cycle of insolation and is punctuated by prominent millennial-scale oscillations of the Chinese Interstadials (CIS) 25 to 22, corresponding to Greenland Interstadials (GIS) 25 to 22. The onset of CIS 25, 24, 23 and 22 is dated to 113.1 ± 0.4, 108.1 ± 0.3, 103.7 ± 0.3 and 91.4 ± 0.6 kyr BP in the Sanxing record, respectively. The end of CIS 24 and CIS 22 is constrained to 105.5 ± 0.4 and 87.7 ± 0.3 kyr BP, respectively. A centennial-scale precursor event at 104.1 ± 0.3 kyr BP preceding CIS 23 is clearly registered. These events in the Sanxing record are synchronous with those identified in stalagmites from the European Alps (NALPS), except for the onset of GIS 25 and the end of GIS 22, and differ by up to 2.3 kyr from the corresponding ones in Greenland ice core records. The high degree of similarity of the δ 18 O records between Sanxing Cave and Greenland supports a Northern Hemisphere forcing of the ASM. The anti-phase relationship of δ 18 O records between Sanxing stalagmites and Antarctic ice cores suggests an additional ASM linkage to the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

The Ili River originates in the Tian Shan Mountains of Northwest China before flowing into Kazakhstan and Lake Balkash. Melting snow and ice are its major contributors. We analyzed glacial changes in the upper Ili River basin between the 1960s and 2007/2009 using topographic maps and satellite imagery from a Landsat TM. The relationships between glacial changes and glacial size, topographic factors, and debris cover were examined. Our results found that total glacial area decreased by 485 ± 177.3 km2 (24.2% ± 8.8%) during the study period, and there were no advancing glaciers. Additionally, 331 glaciers disappeared and 18 disintegrated into two or three smaller glaciers. This study demonstrated a linear relationship between glacial area change and elevation. Changes in glaciers smaller than 1 km2 were affected by both glacial size and topographic factors, while larger ones were affected by size only. Area losses in debris-covered glaciers were smaller by 2.5% to 7.5% compared to clean ice of the same size in this basin. As in other glaciated regions, glacial retreat in the Ili River basin is attributed to global warming. The slightly increasing precipitation over the study period could not offset the ice melting. [ABSTRACT FROM AUTHOR]

Field investigation has shown that the middle reaches of the Yarlung Zangbo River, in Tibet (known as the Bhramaputra River in reaches downstream) has 11 terraces. The ages of these terraces were determined as follows: T11>2000 ka, T10 = 1783 ka, T9 = 1238 ka, T8 = 683 ka, T7 = 382 ka, T6 = 150 ka, T5 = 82 ka, T4 = 67 ka, T3 = 43 ka, T2 = 28 ka and T1 = 10 ka. These terraces formed during several stages of the Quaternary when the Tibetan Plateau was uplifting, recording tectonic-climatic cycles or subcycles of 1.2, 0.4, 0.1, 0.04 and 0.02 million years duration. The tectonic-climatic cycles identified by this study are correlated with red soil and palaeosol records. The preservation of the Oligocene to Early Miocene conglomeratic Dazhuka Formation, close to the present altitude of the main planation surface of the Tibetan Plateau and occurring only in the Yarlung Zangbo valley, suggests that this river has existed since at least 7 Ma. Discoveries of old and thick fluvial gravel layers extending to within 630 m of the valley floor show that the Yarlung Zangbo River was already incised by 2000 m or more below the surface of the Tibetan Plateau, that much of the incision from plateau to valley floor had been accomplished and that the plateau was already substantially uplifted prior to the Quaternary. In addition to its importance for understanding the evolution of the Tibetan Plateau, this study documents the impact of varying rates of tectonic uplift on river development. [ABSTRACT FROM AUTHOR]

Abstract: The geochemistry and petrography of a stalagmite from Wanxiang Cave in central China provide a paleoclimate record of the Penultimate Glacial Maximum (PGM) suggesting unexpectedly abundant non-monsoonal atmospheric precipitation at the nadir of the PGM. Eleven U–Th (230Th) ages from 149 to 140ka BP place the stalagmite in Marine Isotope Stage 6b, coincident with the greatest benthic marine δ18Ocalcite values of MIS 6. Carbon and oxygen stable isotope data, measurements of layer-specific width, positions of surfaces of non-deposition or dissolution, changes in the character and thickness of seemingly annual layers, changes in concentration of organic acids within the stalagmite's calcite, and patterns in the Mg concentration of that calcite all combine to give a coherent paleoclimate record. These data suggest that the stalagmite represents a wetter period than before or after its growth, with the wettest and coldest phase at 145 to 144ka BP. This extreme in climate yields a striking correlation with the LR04 stack of oxygen isotope records from marine benthic forams, if the latter is subjected to a 4500-year chronological adjustment previously suggested by U–Th data from corals. The timing of the Wudu stalagmite's deposition combines with findings elsewhere to suggest that the PGM was the most extreme of later Pleistocene glacial maxima. Petrography and U–Th age determinations suggest dramatic changes in climate during the PGM. At the beginning (149–146ka BP) and end (143–140ka BP) of the stalagmite's growth, abrupt (century-scale) drying caused lengthy hiatuses as dripwater to the stalagmite diminished. On the other hand, delivery of water to the stalagmite during the wettest phase (145–144ka BP) caused dissolution of previous layers of the stalagmite. Enhanced atmospheric precipitation during the cold of a glacial maximum is unexpected because, within the spectrum of Holocene climate, cooler conditions lessen the impact of the East Asian monsoon. Changes in the character of stalagmite layers indeed suggest weakened to negligible influence of the East Asian monsoon during the nadir of the PGM. However, data from the stalagmite are compatible with atmospheric precipitation from westerly winds that today reach only northwestern China but that may have been deflected southward in the PGM by southward migration of the Siberian High. This unexpected significance of the Westerlies during the PGM may be a result of the hypothesized extreme nature of the PGM relative to other glacial maxima of the later Pleistocene. [Copyright &y& Elsevier]

Abstract: The Kanas River originates on the southern slope of Youyi Peak, the largest center of modern glaciation in the Altai Mountains in Central Asia. Glaciers advanced and retreated repeatedly during Quaternary glacial–interglacial cycles in the Kanas River valley, and four moraine complexes and associated glaciofluvial deposits are preserved in the valley. Optically stimulated luminescence (OSL) dating has been used to determine ages of glaciofluvial deposits (sand lenses sandwiched between tills in moraines) using a single aliquot regenerative-dose (SAR) protocol. Based on dating results from this and previous studies (including 14C, electron spin resonance (ESR) and OSL dates) and geomorphic relationships, the innermost moraine complex was concluded to deposit during the Little Ice Age (LIA), the second (Akekule) moraine complex was deposited during the Neoglacial, the third (Kanas) moraine complex was deposited during the last glacial cycle (marine oxygen isotope stage (MIS) 2–4) and the outermost set of moraines is MIS 6 in ages (penultimate glaciation). The Kanas moraine complex could be divided into three subsets (III1, III2 and III3), with inferred ages of MIS 2, mid-MIS 3 and MIS 4, respectively, which is consistent with moraine records from other areas in Central Asia and climate reconstructions from the Guliya ice core. The glaciers in the Kanas valley at their maximum extents during the LIA, Neoglacial, last glaciation and penultimate glaciation were 13.8 km, 32 km, ∼100 km, and ∼120 km long, respectively. [Copyright &y& Elsevier]

The article discusses a study which examined the climate fluctuation record from the Salawusu River Valley in China during the early last glacial. The study also investigated whether these fluctuations were similar to the Dansgaard-Oeschger events recorded in the polar ice cores and stalagmites during the period. A description of the study area and methods is provided. Also discussed are the details of the findings.

Abstract: A 425cm core has been collected from the Gantang subalpine peat bog, in Pingnan County, Fujian Province of Southern China. High-resolution pollen analysis of the core has allowed for the reconstruction of past vegetation and climate changes over the last 50,000years. Today, Fujian province is located in the eastern part of middle subtropical zone where the dominant vegetation is evergreen broadleaved forest that receives its precipitation from the East Asian Monsoon. The pollen record testifies that the vegetation in Fujian varied between subtropical evergreen and warm temperate deciduous forests during the last glacial-interglacial cycle. It appears that during Marine Oxygen Isotope Stage 3, this area was covered with broadleaved forest suggesting warm and wet subtropical condition, whereas the flora was quite different with many ancient elements. The Last Glacial Maximum is distinguished by an increase in warm temperate deciduous taxa, particularly Fagus and Alnus accompanied by abundant Ericaceae, implying a spatial shift of zonal vegetation during this coldest episode in the world. Local swamp developed soon after the Younger Dryas event coinciding with the formation of peatlands in the Northern Hemisphere possibly linked with atmospheric carbon accumulation. A rapid increase in evergreen broadleaved taxa that dominated the local forest occurred at ~ca. 8.2calka BP, indicating the inception of the regional thermal maximum during the Holocene, which was generally characterised by more humid conditions. The middle to late Holocene sees a progressive decline in arboreal elements, and an increase in grasses and Ericaceae. These changes beginning from around 4kacal BP were concordant with the general weakening of the East Asian Monsoon during the Holocene, corresponding with an orbitally induced reduction of boreal summer insolation. This is the first terrestrial high-resolution record from eastern part of middle subtropical areas that evaluates the forest changes through the last glacial-interglacial cycle. [Copyright &y& Elsevier]

Abstract: The effects of climatic conditions on the delivery patterns of suspended solid and dissolved matter are evaluated by examining their correlation with air temperature, precipitation and runoff from glacial and non-glacial catchments at the headwaters of Urumqi River in eastern Tianshan, central Asia. The results show that the physical and chemical weathering fluxes (168 and 23tkm−2 yr−1, respectively) associated with the glacial catchment are higher than those of the non-glacial catchment (34 and 12tkm−2 yr−1, respectively). Significant linear correlations are found between river fluxes and air temperature in both catchments. For each degree of temperature increase, the runoff, physical weathering flux and chemical weathering flux from the glacial catchment increase by 12%, 16% and 5%, respectively. On the other hand, in the non-glacial catchment, these values are 9%, 13% and 15%, respectively, if the temperature is below 4°C; the variations in runoff, physical and chemical weathering fluxes are irregular when the temperature exceeds 4°C. Such a pattern for the non-glacial catchment during the melt season may be due to the influence of multiple water sources. In contrast, the relation to precipitation is relatively weak in both catchments. Furthermore, although the glacial catchment has a higher increasing rate of physical weathering flux in response to temperature increase than the non-glacial catchment, this is not the case for the chemical weathering flux, suggesting that glaciers play an important role in the effect of air temperature change on physical weathering flux. [Copyright &y& Elsevier]

Abstract: The fifth segment of the Milanggouwan stratigraphical section (MGS 5) in the Mu Us Desert provides high-resolution geological information on environmental variations during the Last Interglacial. The analysis of grain content (<50μm), organic content, SiO2, Al2O3, TOFe, and SiO2–(Al2O3 +TOFe) ratios in the MGS 5 suggest that there were 17 kiloyear-scale climate fluctuations in the Last Interglacial, including 9 warm events (W1–W9) and 8 cold events (C1–C8), dominated by the East Asian summer monsoon and winter monsoon respectively. The analysis also suggests that the Eemian interglacial was unstable, with 3 warm events (W7–W9) and 2 cold events (C7–C8), indicating that climate fluctuations affected the East Asian monsoon in the Mu Us Desert during the Last Interglacial. The change cycles and the nature of the kiloyear-scale climate events have a close temporal relationship with the Greenland ice-core oxygen isotope data, suggesting that the climate forming mechanism was affected by polar weather, North Atlantic sea ice, range of the Eurasian ice front, and movement of the Arctic frontal, all of which affect the intensity of the Siberian–Mongolian high pressure region through the movement of the cold air mass. [Copyright &y& Elsevier]

Abstract: Here we construct a Pleistocene astronomical timescale for the Nihewan fluvio–lacustrine sediments (North China), via tuning a stacked summer monsoon index generated from grain size and low-field magnetic susceptibility records to orbital obliquity and precession. Combining the summer monsoon records retrieved from the Nihewan and the Chinese loess deposits in North China on the one hand, and those from the stalagmites and the marine deposits in South China on the other, the Asian summer monsoon records from North and South China appear to show different orbital rhythms during the Pleistocene. The monsoon records from both the Nihewan Basin and Chinese Loess Plateau are equally characterized by dominant obliquity (41kyr) before ~0.9Ma and dominant eccentricity (100kyr) after this time, closely following the marine δ18O record. In contrast, the δ18O record of stalagmites from South China (Wang et al., 2001, 2008b; Cheng et al., 2009) and the iron oxide proxy record from the South China Sea (Zhang et al., 2007, 2009; Ao et al., 2011), which are considered as a proxy indicator of the Asian summer monsoon intensity in South China, reveal a dominant cyclicity of precession (23kyr) over the past 1.8Myr, closely following the solar insolation curve instead. We further present a possible interpretation of the different orbital rhythms in the Asian summer monsoon records from North and South China. The orbital rhythm in the summer monsoon records from North China is mainly modulated by the migration of the Asian summer monsoon due to changes in sea level and Northern Hemisphere ice volume during glacial–interglacial cycles. Strong summer monsoon may have reached North China mainly during interglacial periods. During glacial periods when the sea level was low and Northern Hemisphere ice volume was large, the southeasterly migration of summer monsoon would make North China beyond the reach of the summer monsoon. Thus the summer monsoon records from North China primarily show a cyclic oscillation similar to the glacial–interglacial climate cycles as indicated by cycle-by-cycle correlation between monsoon and marine oxygen isotope records. However, the summer monsoon always prevailed over South China during both glacial and interglacial periods. Therefore, the orbital-scale variability of the summer monsoon in South China shows a direct response to the orbital variations in the low-latitude summer insolation, without significant influence from the migration of monsoon during glacial–interglacial cycles. [Copyright &y& Elsevier]

Abstract: Using the results of 25 climate models under the framework of the Paleoclimate Modelling Intercomparison Project (PMIP) and available proxy data, this study examines the regional climate of China during the Last Glacial Maximum (LGM: 21,000years ago). Compared to the baseline climate, results show that annual surface temperature decreased by 2.00°–7.00°C in China during that period, with an average of 4.46°C, for the ensemble mean of all models. Annual precipitation and evaporation during the LGM were 5–40% less than the baseline values, with an average reduction of 20% (0.60mm/day) and a reduction of 21% (0.41mm/day) at the national scale, based on results from 15 out of the 25 models. These models were selected for their ability to simulate the modern precipitation climatology and for the availability of suitable evaporation data. Both the geographical distribution and magnitude of changes in surface temperature, precipitation, and evaporation during the LGM varied with the seasons and with the models, particularly at the sub-regional scale. Model-data comparisons revealed that the 25 models successfully reproduced the surface cooling trend during the LGM, but they failed to reproduce its magnitude in all four regions of comparison, particularly in the Hexi Corridor and in North and Northeast China. The simulations with computed sea surface temperatures (SSTs) were in better agreement with proxy estimates of surface temperature than those with prescribed SSTs. On the other hand, large-scale LGM-minus-baseline anomalies in annual precipitation minus evaporation agreed well, in a qualitative manner, with lake status-based reconstructions of changes in annual water budgets in East China and the region of 35°–42°N, 74°–97°E. On the eastern Qinghai–Tibetan Plateau, drier climates from the 15 models agreed with pollen-based reconstructions. For most parts of West China excluding the Qinghai–Tibetan Plateau, the simulations with computed (prescribed) SSTs are consistent (inconsistent) with reconstructed moister conditions. [Copyright &y& Elsevier]

The modern Indian summer monsoon (ISM) is characterized by exceptionally strong interhemispheric transport, indicating the importance of both Northern and Southern Hemisphere processes driving monsoon variability. Here, we present a high-resolution continental record from southwestern China that demonstrates the importance of interhemispheric forcing in driving ISM variability at the glacial-interglacial time scale as well. Interglacial ISM maxima are dominated by an enhanced Indian tow associated with global ice volume minima. In contrast, the glacial ISM reaches a minimum, and actually begins to increase, before global ice volume reaches a maximum. We attribute this early strengthening to an increased cross-equatorial pressure gradient derived from Southern Hemisphere high-latitude cooling. This mechanism explains much of the nonorbital scale variance in the Pleistocene ISM record. [ABSTRACT FROM AUTHOR]

Geomorphological observations of palaeoglaciation around the southern flank of Mount Kailash (Serlung Chu valley) are presented. Three distinct events of glaciation with decreasing magnitude (Kailash stage (KS)-I to KS-III) are well represented by the trails of lateral moraine. Inferred chronology of the glaciations suggests that the KS-I event pre-dates the Last Glacial Maximum (LGM), KS-II is attributed to the LGM, whereas KS-III corresponds to the early/mid Holocene. The push moraine and the exposed glaciated bedrock proximal to the Mount Kailash are assigned to the Little Ice Age (LIA). A decrease in glacier ice volume after KS-III glaciation is attributed to the decrease in monsoon and an increase in the summer temperature after LIA. [ABSTRACT FROM AUTHOR]

Abstract: A sediment core from a closed basin lake (Lake Kuhai) from the semi-arid northeastern Tibetan Plateau was analysed for its pollen record to infer Lateglacial and post glacial vegetation and climatic change. At Lake Kuhai five major vegetation and climate shifts could be identified: (1) a change from cold and dry to relatively warmer and more moist conditions at 14.8 cal ka BP; (2) a shift to conditions of higher effective moisture and a stepwise warmer climate at 13.6 cal ka BP; (3) a further shift with increased moisture but colder conditions at 7.0 cal ka BP; (4) a return to a significantly colder and drier phase at 6.3 cal ka BP; (5) and a change back to relatively moist conditions at 2.2 cal ka BP. To investigate the response of lake ecosystems to climatic changes, statistical comparisons were made between the Lake Kuhai pollen record and a formerly published ostracod and sedimentary record from the same sediment core. Furthermore, the pollen and lacustrine proxies from Lake Kuhai were compared to a previously published pollen and lacustrine record from the nearby Lake Koucha. Statistical comparisons were done using non-metric multidimensional scaling and Procrustes rotation. Differences between lacustrine and pollen responses within one site could be identified, suggesting that lacustrine proxies are partly influenced by in-lake or local catchment processes, whereas the terrestrial (pollen) proxy shows a regional climate signal. Furthermore, we found regional differences in proxy response between Lake Kuhai and Lake Koucha. Both pollen records reacted in similar ways to major environmental changes, with minor differences in the timing and magnitude of these changes. The lacustrine records were very similar in their timing and magnitude of response to environmental changes; however, the nature of change was at times very distinct. To place the current study in the context of Holocene moisture evolution across the Tibetan Plateau, we applied a five-scale moisture index and average link clustering to all available continuous palaeo-climate records from the Tibetan Plateau to possibly find general patterns of moisture evolution on the Plateau. However, no common regional pattern of moisture evolution during the Holocene could be detected. We assign this to complex responses of different proxies to environmental and atmospheric changes in an already very heterogeneous mountain landscape where minor differences in elevation can cause strong variation in microenvironments. [Copyright &y& Elsevier]

Abstract: Intense tectonic movement occurred along the northeastern margin of the Tibetan Plateau 3–4Ma. During the same time period, global climate changed from a period of stability to a period of frequent and abrupt changes, which prevented fluvial and glacial systems from establishing a state of equilibrium. Thus, it is difficult to directly attribute the 3–4Ma coarse-grained sediment accumulation in East Asia to climate change or tectonic activity. This study compares Late Cenozoic multi-proxy records from the Chinese Loess Plateau (CLP) to the low-latitude grain size, sea level and benthic δ 18O records from the South China Sea (SCS) and the high latitude grain-size record from Lake Baikal. All records suggest a steady and persistent cooling since ~4Ma, which correlates well with those cooling records from other regions around the world. This coincided in timing with the modeling results that the closure of the Central American Seaway (CAS) initiated strengthening of Atlantic meridional overturning circulation between 4.8 and 4.0Ma which led to both warming of the Northern Hemisphere (NH) and cooling of the Southern Hemisphere (SH). Cooling of the SH would induce a marked development of the Antarctic ice sheets at ~4Ma, pushing the Intertropical Convergence Zone (ITCZ) northward. This was superimposed on warming of the NH and brought more precipitation to the middle latitudes of the NH, resulting in increases in coarse-grained sediments in the Sikouzi section from the western CLP since 4.2Ma. Notably, the absence of coarse-grained sedimentation in the Sikouzi section during 3.0-2.1Ma and the gradual decrease in coarse-grained peaks since 2.1Ma reflected by the Sikouzi grain-size record probably resulted from stepwise increase in the NH ice volume pushing the ITCZ southward. On the other hand, development of the Antarctic ice sheets would induce global cooling and enhancement of physical weathering, initiating increases in sedimentation rates as well as increases in grain size from Lake Baikal to the CLP to the SCS. Therefore the closure of the CAS during 4.8–4.0Ma and its influence on ocean heat transport was possibly the major forcing factor for global cooling since 4Ma. A persistent and steady cooling during 4–3Ma probably made a significant contribution to the establishment of the NH ice sheets at 2.75Ma ago. [Copyright &y& Elsevier]

Based on observations of the equilibrium line altitude (ELA) of the Qiyi Glacier in the Qilian Mountain, we established a statistical model between ELA and its major influencing factors, warm season air temperature (air temperature averages for September, July and August) and cold season precipitation (total precipitation in the period January through March). Warm season air temperature was the leading climatic factor influencing ELA variations. The glacier ELA ascends (descends) 172 m when warm season air temperature increases (decreases) by 1°C, and ascends (descends) 62 m when cold season precipitation decreases (increases) by 10%. In the period 1958-2008, the glacier ELA showed a general increasing trend, ascending 230 m and reaching its highest altitude in 2006 at 5131 m a.s.l., close to the glacier summit. If future climate is similar to that in the period 2001-2008, the Qiyi Glacier will not stabilize until it retreats by 2.08 km. [ABSTRACT FROM AUTHOR]

17.81 m sediment core from Lake Naleng, a freshwater lake in the south-eastern part of the Tibetan Plateau was examined for its non-pollen palynomorph (NPP) composition. The frequencies of 15 NPPs and three aquatic pollen types were determined in 160 samples. Since the origin of several NPP types is still unknown, multivariate analysis, supported by findings from the corresponding fossil pollen flora, was carried out to extract information about their ecological environments. The analysis allowed a classification of all microfossils in four groups of environmental response, which provided an approach to tracing lake history and palaeoclimatic changes in the area since the Late Glacial (since 17,700 cal years b.p.). Unstable lake conditions and a low organic productivity were reconstructed for the Late Glacial before 14,600 cal years b.p. with high inputs of terrestrial material. Climate conditions became wetter during the Bølling/Allerød interval indicated by high productivity in the lake. After a short climate deterioration (12,500-11,500 cal years b.p.), stable lake conditions were inferred from the record. During the late Holocene (since 2,700 cal years b.p.) changes in the NPP composition might be related to human impact, the latter being inferred from the pollen data through the presence of grazing indicators. [ABSTRACT FROM AUTHOR]

Abstract: Based on the glacial flood events and climate change in the Yarkant River basin during the past 50 years, the study investigated the long-term change of temperature and precipitation, the characteristics of glacial floods, the origin of sudden flood release, the suggested flood mechanism of glacial lakes and the relationship between glacial floods and climate change. Results showed that there was an obvious increase in the temperature of the basin since 1987. Specifically in the mountainous area, the significantly increasing temperature in the summer and autumn seasons accelerated the melting rate of glaciers and caused glacial-lake burst. Sudden flood release occurred frequently. The frequency of glacial-lake outburst floods was 0.4 times/a during the period 1959–1986 and increased to 0.7 times/a during 1997–2006. Peak discharge also increased. There were seven floods with peak discharge over 4000m3/s from 1959–2006, and three occurred after 1997. The increasing frequency and magnitude of glacial outburst floods mirrored the effect of climate warming on glaciers. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies of the eolian deposits in northern China have extended the East Asian monsoon history back to the early Miocene. However, the relative intensities of monsoonal winds and precipitation and the extent of their coupling prior to the Pleistocene epoch remain poorly constrained, mainly due to uncertainties in the interpretation of proxy indices generated from the Mio–Pliocene Red Clay sequences. Here we reconstruct East Asian monsoon oscillations over the past 7Ma using magnetic susceptibility and carbonate content as summer monsoon (precipitation) proxies, and quartz grain size as a winter monsoon (wind intensity) index. Our results suggest that precipitation and wind intensity exhibited significant orbital-scale variations prior to 4.2Ma, followed by slightly damped variability between 4.2 and 2.75Ma. Subsequently, East Asian monsoon circulation experienced two large shifts at about 2.75 and 1.25Ma, characterized by stepwise strengthening of glacial wind and interglacial precipitation. A remarkable change in East Asian monsoon seasonality occurred around 3.15–2.75Ma. Prior to 3.15Ma, strong winds were positively correlated with high effective precipitation, whereas after 2.75Ma strong winds were negatively correlated with heavy precipitation. This shift was probably induced by a change from an insolation-forced system to one strongly influenced by the combined effects of the phased uplift of the Himalaya–Tibetan Plateau and the simultaneous development of the Northern Hemisphere ice sheets. [ABSTRACT FROM AUTHOR]

Abstract: The Muzart River originates on the southeastern slope of Tumur Peak, the largest center of modern glaciation in the Tianshan Range. Glacial landforms and sediments indicate that there are four major Quaternary glaciations in this drainage. The glacial landforms contain considerable information about the changes of the ancient glaciers. Dating the landforms allows the temporal and spatial variations of the ancient glaciers in this valley to be understood and provides essential information in reconstructing the paleoenvironment in this region. Electron spin resonance (ESR) dating of a well-exposed section, the multiple end moraines of the Pochengzi glaciation (the third set of moraines), and the local outwash and fluvial sediments on the Kezibulake glacial plain (the fourth set of moraines) was carried out using germanium (Ge) centers in the glacial quartz grains, which are sensitive to both sunlight and grinding. Eleven depositional ages have been determined. Based on the dating results, the principle of superposition and the glaciations pattern reported in the adjacent valley, the Pochengzi end moraines were determined to be deposited during the major glacial intervals that are equivalent in age to marine oxygen isotope stages (MIS) 2, mid-MIS 3 and MIS 4 and the Kezibulake glacial deposits were determined to be equivalent in age to MIS 6. Furthermore, the Tugaibieliqi end moraine (the second set of moraines) was deposited during the Neoglaciation (a cold period between 3 and 4 ka) and the 3–4 end moraines located at the terminuses of the modern glacier were deposited during the Little Ice Age. The ages of the Pochengzi glacial deposits can be subdivided into three clusters, they are 13.6–25.3 ka, 39.5–40.4 ka and 64.2–71.7 ka, respectively. The largest local last glacial maximum (LGML) occurred during MIS 4 rather than the global Last Glacial Maximum (LGMG) of MIS 2. Furthermore, a glacier that is slightly larger than that of MIS 2 developed in this drainage during mid-MIS 3. The ancient Muzart glaciers were compound valley glaciers during the Neoglaciation, MIS 2 and mid-MIS 3, and piedmont glaciers during MIS 4 and MIS 6. [Copyright &y& Elsevier]

Abstract: An abrupt climatic change during the MIS 5a/4 transition is evident in the loess records of China (S1/L1). Proxies including geochemical elements, grain size, soil color, magnetic susceptibility and carbonate (CaCO3) content indicate a warming interval, which lasted approximately 3ka, during the MIS 5a/4 transition in both the Wangguan and Shagou loess sections, located in Sanmenxia (Henan Province) and Wuwei (Gansu Province), respectively. Both the winter and summer monsoon proxies demonstrate that this warming interval occurred at the same time in both sections (nearly 70.5–73.6ka BP), with maximum warming from 71.4 to 72.0ka BP. This study suggests a universal abrupt warming interval in the East Asia monsoon region at this time. Comparisons with marine, terrestrial and ice-core records indicate this event was very likely an abrupt global warming interval during the last glacial–interglacial transition. [Copyright &y& Elsevier]

Abstract: The relationship between climate and glacial equilibrium-line altitude (ELA) during the Last Glacial Maximum (LGM) has recently received considerable interest. However, in the headwaters of Urumqi River in northwest China, a systematic reconstruction for the paleo-ELAs had not been completed to permit regional and large-scale paleoclimate inferences. Recent improvements in dating and understanding of glacial extents provide the possibility to use glacial reconstruction to infer the paleoclimate. To improve the ability to obtain paleoclimate information, the ELAs during the local LGM (MIS2–3) and modern time (1998–2004) were constructed by using an integrated method. The regional tectonic uplift is considered when calculating the LGM ELAs in order to improve their precision and thus obtain a better estimate of the paleoclimate. The estimated ELA values were input into a robust equation to derive the forcing paleoclimatic conditions. During the local LGM in the study area, the ELA was between 3420 and 3560 m a.s.l., 493–633 m lower than modern ELA. Considering energy and mass balance in the equation to account for the ELA decrease, during the LGM, the temperature decreased by 5.42–6.30 °C and the precipitation was ∼30% compared to the present. [Copyright &y& Elsevier]

Abstract: Records of two loess sections located in mid-eastern and western margins of the East Asian Monsoon area captured 20 Dansgaard-Oescher events and six Heinrich events. All these suggested that the climate in the East Asian Monsoon area fluctuated rapidly on millennial to century timescales during the whole Last Glacial. We found that these loess-based events of rapid climate fluctuations were generally synchronous with those of GRIP records, but that there were differences between the Shagou loess section in the west and the Wangguan loess section in the east: the former was more sensitive to climate change than the latter. Compared with earlier studies on loess records covering the Last Glacial from neighboring areas, we discovered that the magnitude of Dansgaard-Oeschger cycles decreased gradually from west to east and we suggest that it resulted from the combined effect of the Westerlies and the East Asian Monsoon. [Copyright &y& Elsevier]

Abstract: Two stalagmites (C996-1 and C996-2) collected from the Jiuxian Cave in the Shaanxi Province in central China have been studied with U-series dating and stable isotope analysis. Thirty-eight 230Th dating results showed that the stalagmite C996-1 was continuously deposited through the last 8.5ka BP (thousand years before present, present=1950AD), and C996-2 was deposited through the last 19ka BP excluding two growth hiatuses between 8.3 and 5.7ka BP, and 15.4 and 11.9ka BP. With a relatively stable boundary condition, we interpret the δ 18O of speleothem calcite as most indicative of the amount of summer monsoon precipitation, although temperature and other factors might have some minor impact. The δ 18O records show notable changes within the last glacial maximum (LGM), resembling other East Asian monsoon records such as those from the Hulu and Sanbao Caves, suggesting that significant monsoonal climate changes occurred in eastern Asia as far north as the Qinling Mountains during the LGM interval. A comparison of our records to precisely dated contemporaneous speleothem records from other caves shows that the increasing trend of δ 18O during the Holocene commenced as early as ∼7.5ka BP in the low-latitude monsoonal area, i.e. the Hoti Cave, while at higher latitudes this shift occurred later, such as ∼7.0ka BP in the Dongge Cave, ∼5.3ka BP in the Heshang Cave, ∼4.7ka BP in the Sanbao Cave and ∼4.5ka BP in the Jiuxian Cave. These results imply an asynchronous change of the summer monsoon precipitation occurred in East Asia during the Holocene. The asynchrony may be related to the responses of a coupled tropical and subtropical monsoon system to changes of the insolation and the differences in thermal forcing, which result from the complex geographical configuration. The variation of sea surface temperature (SST) in the western tropical Pacific may also have important impacts on the summer monsoon precipitation changes in central and northern China because it affects the Northwestern Pacific Subtropical High, a monsoon-front regulator. More robust tests are needed to confirm this phenomenon and to evaluate the contribution of different factors in detail. [Copyright &y& Elsevier]

Abstract: We present a late glacial pollen record (17,700 to 8500 cal yr BP) from a Lake Naleng sediment core. Lake Naleng is located on the southeastern Tibetan Plateau (31.10°N 99.75°E, 4200 m) along the upper tree-line. Variations in the summer monsoon are evident from shifts in vegetation that correspond to late glacial climate trends from other monsoon-sensitive regions. Alpine steppe was recorded between 17,700 and 14,800 cal yr BP, indicating low effective moisture at the study site. Expansion of alpine meadows followed by advances in the position of tree-line around Lake Naleng suggest that climate became warmer and wetter between ∼14,800 and 12,500 cal yr BP, probably representing an enhancement of the Asian monsoon. Climatic cooling and reduced effective moisture are inferred from multivariate analysis and the upward retreat of tree-line between ∼12,500 and 11,700 cal yr BP. The timing and nature of these shifts to warm, wet and then cold, dry climatic conditions suggest that they correspond to the Bølling/Allerød and Younger Dryas intervals. Abies-Betula forests, representing warm and moist conditions, spread during the early Holocene. [Copyright &y& Elsevier]

Abstract: A low-resolution strontium isotopic ratio (87Sr/86Sr) record coupled with a high-resolution Sr concentration profile covering the last deglacial period were obtained for a stalagmite, SJ3, collected from Songjia Cave, northeast Sichuan province, Central China. Both Sr and 87Sr/86Sr display significant variations during the period between 20 and 10ka, which correlate well with oxygen isotope records from Greenland ice cores and speleothems in the East Asian summer monsoon regime, with higher Sr and more radiogenic 87Sr/86Sr values occurring during cold-dry climatic phases and vice versa. The Sr in SJ3 shows a negative linear relationship between 87Sr/86Sr and 1/Sr, suggesting the binary mixing of two end-members, the host rock of Late Permian limestone with a relatively lower 87Sr/86Sr ratio (∼0.7071) and an exotic Sr source with a relatively radiogenic 87Sr/86Sr ratio (∼0.7109 deduced from the 87Sr/86Sr-1/Sr correlation). Atmospheric dust activity was suggested to be the most probable factor influencing the two indices. Because the carbonate fraction in wind-blown dust is enriched in Sr and has a more radiogenic 87Sr/86Sr ratio, enhanced atmospheric dust activity under stronger Asian winter monsoon which is associated with cold-dry climate would lead to higher Sr concentrations and more radiogenic 87Sr/86Sr ratios in SJ3 and vice versa. This interpretation is supported by the general parallelism of the two Sr indices to winter monsoon proxy from East Asia such as the dust flux and quartz median diameter in Luochuan loess profile during the same period. This study suggests that the speleothem 87Sr/86Sr ratio and Sr concentration, especially the former in northeastern Sichuan Province can be used to investigate the atmospheric dust activity and Asian winter monsoon. [Copyright &y& Elsevier]

Abstract: Our 12.81m long record from Lake Ximencuo provides insight into the Lateglacial and Holocene evolution of the lake and the Nianbaoyeze glacier in its catchment, and the regional climate history since ∼19kyr. Lake Ximencuo was a permanent deep lake throughout its history. In contrast to numerous lakes on the Tibetan Plateau which experienced shallow lake levels or even desiccation during the Lateglacial, Lake Ximencuo was fed by large quantities of meltwater in the Lateglacial. The existence of glaciated upper catchment areas is apparently a prerequisite for lakes on the Tibetan Plateau which maintained relatively high water levels during the generally cold and dry periods following the global LGM (∼21kyr). A minor re-advance of the Nianbaoyeze glacier was recorded coeval with the Greenland Stadial 2a (∼16.4 and 14.5kyr), followed by rapid warming apparently synchronous with the Greenland Interstadial 1. Warmest conditions were recorded at Lake Ximencuo during the early Holocene which was punctured by a remarkable pulse of climate deterioration around 8.3kyr. This spell represents probably the 8.2kyr event of the North Atlantic region, suggesting that it had a significant impact on the Tibetan Plateau. Colder conditions of longer duration occurred from 4.7 to 3.7kyr, apparently in phase with numerous records signalling colder and drier conditions on the Tibetan Plateau. Two minor spells of colder conditions and probably catchment erosion were recorded in the late Holocene between 2.0 and 1.4kyr and between 0.5 and 0.1kyr with the latter representing the Little Ice Age. It is unclear, whether human activities may have accelerated or even solely triggered the late Holocene erosion events. [Copyright &y& Elsevier]

The height of mountain ranges reflects the balance between tectonic rock uplift, crustal strength and surface denudation. Tectonic deformation and surface denudation are interdependent, however, and feedback mechanisms—in particular, the potential link to climate—are subjects of intense debate. Spatial variations in fluvial denudation rate caused by precipitation gradients are known to provide first-order controls on mountain range width, crustal deformation rates and rock uplift. Moreover, limits to crustal strength are thought to constrain the maximum elevation of large continental plateaus, such as those in Tibet and the central Andes. There are indications that the general height of mountain ranges is also directly influenced by the extent of glaciation through an efficient denudation mechanism known as the glacial buzzsaw. Here we use a global analysis of topography and show that variations in maximum mountain height correlate closely with climate-controlled gradients in snowline altitude for many high mountain ranges across orogenic ages and tectonic styles. With the aid of a numerical model, we further demonstrate how a combination of erosional destruction of topography above the snowline by glacier-sliding and commensurate isostatic landscape uplift caused by erosional unloading can explain observations of maximum mountain height by driving elevations towards an altitude window just below the snowline. The model thereby self-consistently produces the hypsometric signature of the glacial buzzsaw, and suggests that differences in the height of mountain ranges mainly reflect variations in local climate rather than tectonic forces. [ABSTRACT FROM AUTHOR]

The Kaigas, Sturtian, Marinoan, and Gaskiers glaciations are widely recognized in Neoproterozoic. However, in the South China Block only the Jiangkou (Sturtian) and Nantuo (Marinoan) are symbolized by sedimentary records. The Kaigas, recorded by isotopic and chemical proxies, exhibited likely the nature of cold paleoclimate with local mountain glaciation. The correlation of the Doushantuo Formation with the Gaskiers is indicated by the carbon isotope excursion and the dated age from the interval, however the South China Block was then under non-glacial weather. With no paleomagnetic data, the position of the South China Block during the Sturtian glaciation cannot be determined. The paleolatitudes of the South China Block during the Kaigas and Nantuo glaciations are intermediate, even though the Nantuo was once rendered erratically deduced equatorial. In fact, the paleolatitudes of the South China Block during the Neoproterozoic glaciations are all likely at about 30° -40°. [ABSTRACT FROM AUTHOR]

The Late Paleozoic Icehouse (LPI) provides a deep-time perspective for climate-glaciation-environment coevolution and offers potential insights into future climatic and environmental predictions. Most previous studies attributed climatic and environmental changes during the LPI to perturbations of atmospheric p CO 2 , yet the driving mechanism for p CO 2 changes remains controversial. Although the environmental and climatic effects of volcanism have been recognized, its high-resolution geological records and links with changes in atmospheric p CO 2 and climate are rarely reported. We address this by investigating volcanic records (indicating by Hg/TOC ratio) and organic carbon isotope composition (δ13C org) of paralic strata from the latest Gzhelian to Roadian stages in the North China Platform (NCP), China. Four δ13C org negative excursions (latest Gzhelian, middle Artinskian, middle Kungurian and latest Kungurian stages) and two positive isotope plateaus (Asselian and Roadian stages) are identified. Each of the four negative isotope excursions coincides with peaks in Hg/TOC ratio and rising periods of atmospheric p CO 2. The co-occurrence of the negative isotope excursions and Hg/TOC peaks suggests volcanic origins for both the Hg and perturbations in the carbon cycle. The two positive isotope plateaus correspond to the glacial P1 and the climatic transition period to glacial P3 in Australia and to weak periods of volcanism. Our results provide clear insights into volcanism driving perturbations in environment, climate and the carbon cycle in deep time, and support the assertion that volcanism was sufficient to shift global climates from glacial to interglacial through greenhouse gas emissions during the LPI. • Early Permian continental δ13C org record presented from North China Platform. • Negative δ13C org excursions and Hg/TOC ratios identify episodes of volcanism. • Volcanism is important driver for changes in atmospheric p CO 2 and climate. • Two positive δ13C org plateaus correspond to P1 and P3 glaciations in Australia. [ABSTRACT FROM AUTHOR]

Abstract: The provenance of Chinese Loess Plateau sediments is an often-posed question that has not been satisfactorily resolved. Elemental geochemistry characteristics of the deposition may provide important evidence in this regard. To this end geochemical analyses were undertaken on densely sampled strata from four loess sections (one of which is located in Northwestern China at the desert margin and the other three on the Loess Plateau) as well as sediments from the Badain Jaran Desert. It was found that loess deposition on the Chinese Loess Plateau and the northern foot of the Qilian Mountains had strong geochemical similarity during the last glacial cycle, but had remarkable differences with the Badain Jaran Desert samples. It is inferred that the desert was not the most important direct provider of dust material to the Loess Plateau. Rather, one of the main source areas appears to have been the vast silt-rich piedmont alluvial fan distributed at the northern foot of the Qilian Mountains. [Copyright &y& Elsevier]

A sample from the top of the Banxi Group (early Neoproterozoic) in Hunan Province (South China) was dated by the SHRIMP zircon U-Pb method. The resulting age of 725 ± 10 Ma probably solves the debate between the synglacial and the preglacial correlation of the Liantuo Formation and indicates that the Liantuo Formation most likely correlates with the preglacial Banxi Group. Since the Banxi (Danzhou) Group is upwardly transitional to the glacial Jiangkou Group, the age becomes a new maximum age constraint on the onset of the Jiangkou glaciation, which therefore most likely correlates with the Sturtian glaciation. [ABSTRACT FROM AUTHOR]

High-resolution speleothem records from China have provided insights into the factors that control the strength of the East Asian monsoon. Our understanding of these factors remains incomplete, however, owing to gaps in the record of monsoon history over the past two interglacial–glacial cycles. In particular, missing sections have hampered our ability to test ideas about orbital-scale controls on the monsoon, the causes of millennial-scale events and relationships between changes in the monsoon and climate in other regions. Here we present an absolute-dated oxygen isotope record from Sanbao cave, central China, that completes a Chinese-cave-based record of the strength of the East Asian monsoon that covers the past 224,000 years. The record is dominated by 23,000-year-long cycles that are synchronous within dating errors with summer insolation at 65° N (ref. 10), supporting the idea that tropical/subtropical monsoons respond dominantly and directly to changes in Northern Hemisphere summer insolation on orbital timescales. The cycles are punctuated by millennial-scale strong-summer-monsoon events (Chinese interstadials), and the new record allows us to identify the complete series of these events over the past two interglacial–glacial cycles. Their duration decreases and their frequency increases during glacial build-up in both the last and penultimate glacial periods, indicating that ice sheet size affects their character and pacing. The ages of the events are exceptionally well constrained and may thus serve as benchmarks for correlating and calibrating climate records. [ABSTRACT FROM AUTHOR]

The δ18O record in deep-sea sediments show a significant reduced amplitude of the ice volume variations before Marine Isotope Stage 11, about 400 ka ago, with less warm interglacials and less cold glacials. The deuterium temperature and the greenhouse gases records in the Antarctic ice cores show the same feature. As the reduction in the amplitude of climate and greenhouse gases concentration variations before 400 ka BP is present in both deep-sea and ice cores, it is tempting to conclude that this is a worldwide phenomenon. This is not necessarily true, at least as far as some of the records, in particular of China and Europe, are concerned. The loess in northern China, the sedimentary core in the eastern Tibetan Plateau and the palaeosols in southern China all record an unusually warm and wet climate during Marine Isotope Stage 13, indicating an extremely strong East Asian summer monsoon. The pollen record from Europe shows that the climatic conditions during the interglacials previous to Marine Isotope Stage 11 are at least as warm as the younger interglacials. During Marine Isotope Stage 13, unusually strong African and Indian monsoon are recorded in the sediments of the equatorial Indian Ocean and of the Mediterranean Sea. Other extreme climate events are also recorded in sediment cores of the equatorial Atlantic, the Pacific, the subtropical South Atlantic Ocean and in the Lake Baikal of Siberia. [ABSTRACT FROM AUTHOR]

Guxiang and Baiyu Glaciations are two previously recognized local glaciations of the Tibetan Plateau. They have been widely used as the reference standard for classifying Late Quaternary glaciations on the Tibetan Plateau and its surrounding mountains. However, the numerical chronologies of both glaciations have been lacking. In this study, cosmogenic 10Be dating was undertaken to define the timing of these two glaciations. The surface boulders deposited by the glaciers of the Guxiang and Baiyu Glaciations have exposure ages of 112.9±16.7-136.5±1 5.8 ka BP and 11.1±1.9-18.5±2.2 ka BP, respectively. It is likely that the Guxiang and Baiyu Glaciations correspond to marine isotope stages 6 and 2,' respectively. [ABSTRACT FROM AUTHOR]

In this paper, nine sediment sequences in the inner desert, desert-loess transitional zone (agro-pastoral transitional zone) and the northern margin of the Loess Plateau were investigated to study the sediments of Mu Us (Maowusu) and Otindaq (Hunshandake) sandy land in northern China since the last glaciation. All of these sequences consisted of the upper Holocene dark paleosol and the lower aeolian sand formed during the last glacial stage. The Mu Us and Otindaq sandy land became the active desert since the last glaciation and covered a larger sandy area than at present. Mu Us sandy land began to show a landform of sandy desert and expanded southward towards the northern boundaries of the Loess Plateau. The Holocene was characterized by the advent of warmer and wetter climatic conditions in northern China, resulting in the rapid growth of surface vegetation and Mu Us and Otindaq sandy land became a steppe. The thickness of surface soil reached up to as much as 50–80 cm. Thick paleosol covered the drift sands, and served as a protective layer for the steppe and farmland. Although the last glacial cycle is far away, paleo-aeolian sands formed during that period are still the material sources of regional desertification. Unreasonable cultivation destroying the Holocene paleosol, combined with dry climate and strong wind would result in activation of paleo-aeolian sand leading to the desertification of the study areas. [ABSTRACT FROM AUTHOR]

A high-resolution loess section in the western Chinese Loess Plateau, Yuanbao Section, was sampled for organic carbon isotopic analyses. The soil organic carbon isotope (δ Corg) varied between -22.6‰ and -27.5‰ during the last glacial at the section. During the last interstadial, the δ Corg values were more negative than those in both early and late periods of the last glacial by 4‰. The isotopic composition indicates a coupled response of the pure C3 plants to the temperature, precipitation and the concentration of atmospheric CO2. Decrease in temperature and the atmospheric CO2 concentration from the last interstadial to Last Glaicial Maximum (LGM) caused the organic carbon isotopes to become positive by 1.5‰ 2.0‰. The amplitude of 4‰ in the δ Corg variation during the last glacial should be mainly caused by the precipitation change. Therefore, the δ Corg variations of the Yuanbao Section during the last glacial period documented the large-amplitude fluctuation of the monsoon precipitation, which is estimated to be 250-310 mm more during the last interstadial than that in the LGM, and 100 mm more than that during early last glacial. The rapid changes of the monsoon precipitation on millennial scale during the last glacial have also been recorded in the isotopic variations in Yuanbao loess section. As the isotopic composition varies complicatedly as shown in the loess-paleosol sequence, it cannot be simply attributed to the abundances of C3 and C4 plants or be used as an indicator of the summer monsoon variations. [ABSTRACT FROM AUTHOR]

Based on Atmosphere-Vegetation Interaction Model (AVIM), the magnitude and spatial distribution of terrestrial net primary productivity (NPP) in China is simulated during three different geological eras, Last Glacial Maximum (LGM), Mid-Holocene (MH) and the present. The simulation shows that the glacial-interglacial variation of East Asian summer monsoon in China is the key factor affecting the NPP change. During the three eras, mean NPPs are 208 g/m²·a, 409 g/m²·a, and 355 g/m²·a. The total NPPs are 2.05 Pg/a, 3.89 Pg/a and 3.33 Pg/a, respectively. The terrestrial NPP in China during warm-humid climate is larger than that during cold-arid eras, and the correlation analysis between NPP and climate factors suggests that temperature is the primary factor affecting the terrestrial NPP during 21 kaBP (LGM), and for 6 kaBP (MH) and the present the primary factor is precipitation. [ABSTRACT FROM AUTHOR]

Abstract: We report C-isotopic data from the cap carbonate overlying the terminal Proterozoic Nantuo diamictites in south China. The C-isotopic measurements reveal a large C-isotopic gradient of ∼3‰ along paleoenvironmental transect from shelf to deep basinal sedimentary facies. The C-isotopic stratification may attribute to the effect of biological pumping in a postglacial ocean. Our results confirm that the sea-level rise was rapid and that atmospheric CO2 was significantly high immediately following deglaciation. [Copyright &y& Elsevier]