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This paper documents a 7800-year proxy record from the Shenjiadian peatland on the Sanjiang Plain in Northeast China. High-resolution plant macrofossil and colorimetric humification methods were used to reconstruct the vegetation and hydrologic history from a 193 cm-long sedimentary profile. Detrended correspondence analysis (DCA) was applied to transform the raw plant macrofossil data into latent indices of peatland water level. The vegetation community transited from an Equisetum fluviatile community to a Carex lasiocarpa community at approximately 3800 cal yr BP and was followed by a Carex-shrub community at approximately 480 cal yr BP. Based on the plant macrofossil DCA axis 1 scores and humification values, we distinguished four hydrologic periods: a wet period from 7800 cal yr BP to 4500 cal yr BP, dry periods up to 1600 cal yr BP, drier periods until 300 cal yr BP, and the driest period from 300 cal yr BP until the present. Through a comparison with other climate records, we suggest that the East Asian summer monsoon (EAM) was the main driving force for vegetation and water level changes to the Shenjiadian peatland through its impacts on precipitation. [ABSTRACT FROM AUTHOR]

This paper is a review of studies of abrupt climate changes (ACCs) during the Holocene published during the past ten years. North Atlantic cold events are indicators of ACCs. As indicated by North Atlantic ice-rafted debris (IRD), there were nine confirmed cold events during the Holocene, occurring at 11.1 kyr, 10.3 kyr, 9.4 kyr, 8.1 kyr, 5.9 kyr, 4.2 kyr, 2.8 kyr, 1.4 kyr, and 0.4 kyr respectively according to most representative results from Bond et al. (1997). However, the identification of chronology has been made with some uncertainties. Considerable climatic proxy data have shown that, during the cold events, substantial climate abnormalities have occurred widely across the globe, particularly in the areas surrounding the North Atlantic. These abnormalities were in the form of high-latitude cold in the both hemispheres, expansion of the Westerlies to low latitudes, drought in the monsoon regions, recession of summer monsoons, and intensification of the winter monsoons. Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic, and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity. [ABSTRACT FROM AUTHOR]

A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of this paper reveal several evidently dry and cold events that may coincide with the Oldest Dryas, the Older Dryas, the Younger Dryas in the late deglacial period. Two relatively wetter and warmer phases occurred in ca. 15,000–14,400 cal yr B.P. and 13,500–12,800 cal yr B.P. respectively may correspond to the Bølling and Allerød warming events. The Younger Dryas event (ca. 12,800–11,500 cal yr B.P.) revealed by multi-proxies was characterized by relatively colder and drier climate. A warmer and wetter climate, occurred in ca. 10,000–6000 cal yr B.P., was consistent with the Holocene Optimum, which coincided with the maximum Northern Hemisphere insolation. The “8.2kyr cool event” and even the “8.8kyr cool event” were indicated as well from our sediment core. A dry mid-Holocene period (ca. 6000–3000 cal yr B.P.) indicated by multi-proxies does not follow the traditional concept of the wet mid-Holocene conditions observed in other regions in China. [ABSTRACT FROM AUTHOR]

Study results in this paper have indicated that the Holocene climate in Xinjiang, Northwestern China has been alternating between wet and dry conditions, and was punctuated with a series of abrupt climate shifts. A sediment core taken from Barkol Lake in the northern Xinjiang of Northwest China was analyzed at 1cm interval for grain-size distribution. Abrupt climate shifts revealed by the grain-size proxy occurred at ca 1.4, 3.0, 4.3, 5.6, 8.0 cal kyr B.P., which were well correlated to both the abrupt shifts recorded in the North Atlantic Ocean (NAO) and the Holocene sea surface temperature (SST) cooling events in the Arabian Ocean. The correlation indicated that the climatic changes in the extreme arid Northwest China were associated with the NAO, probably via the North Atlantic Oscillation-affected westerly winds. The strength and position of westerly winds probably modulated the Siberian-Mongolian high-pressure system (winter monsoon), and played an important role in climate change of Northwest China. Moreover, an evident drought interval during the middle Holocene was also revealed by grain-size proxy. [ABSTRACT FROM AUTHOR]

Traditionally, the mid-Holocene in most parts of China was thought to be warmer with higher precipitation, resulting from a strong Asian summer monsoon. However, some recent researches have proposed a mid-Holocene drought interval of millennial-scale in East Asian monsoon margin areas. Thus whether mid-Holocene was dry or humid remains an open issue. Here, Zhuyeze palaeolake, the terminal lake of the Shiyang River Drainage lying in Asian monsoon marginal areas, was selected for reconstructing the details of climate variations during the Holocene, especially mid-Holocene, on the basis of a sedimentological analysis. Qingtu Lake (QTL) section of 6.92m depth was taken from Zhuyeze palaeolake. Multi-proxy analysis of QTL section, including grain size, carbonate, TOC, C/N and δ13C of organic matter, was used to document regional climatic changes during 9–3 cal ka B.P. The record shows a major environmental change at 9.0–7.8 cal ka B.P., attributed to a climate trend towards warmth and humidity. This event was followed by a typical regional drought event which occurred during 7.8–7.5 cal ka B.P. And a warm and humid climate prevailed from 7.5 to 5.0 cal ka B.P., attributed to the warm/humid Holocene Optimum in this region. After that, the climate gradually became drier. Moreover, comparison of the climate record from this paper with the summer insolation at 30°N indicates that the climate pattern reflecting the Asian monsoon changes was caused by insolation change. [ABSTRACT FROM AUTHOR]

In this paper, the Holocene paleoenvironment change sequence in middle Inner Mongolia was primarily reconstructed on the basis of palynological analysis at the resolution of 70 years on a peat profile, which was located in the northern part of Tumd Plain with its oldest age of 9100 a. B. P. As the consequence indicated, the Holocene climate change in the middle Inner Mongolia had undergone cool→temperate→warm→temperate→cool series, and the history could be divided into 5 epochs: 9100 – 7400 a B. P., with slightly arid and cold climate; 7400 – 5000 a B. P., transitory climate with dynamic fluctuation, earlier period temperate and slightly arid, and later period temperate and slightly humid; 5000 – 4100 a B. P., with warm and humid climate; 4100 – 1350 a B. P., with transitory climate getting arid, as the result of human being’s growing influence; 1350 a B. P. — present, with temperate and slightly arid climate, under strong influence of human being. The warm period of Holocene occurred in 7400 – 4000 a B. P., while the optimal period occurred in 5000 – 4100 a B. P. [ABSTRACT FROM AUTHOR]

Based on the new data of the Quaternary along the coast of Hainan Island, China, this paper puts forward that the Holocene in Hainan Island can be divided into four formations: Wanning formation (Q), Sanya formation (Q), Qiongshan formation (Q) and Ledong formation (Q). Spore-pollen analysis shows that there are 6 spore-pollen zones existed, reflecting two cycles of climatic fluctuation from warm-dry to hot-humid. The climax of hot-humid period occurred 6,000-5,000 years B.P.. Based on theC dating data of the 38 samples representing the positions of ancient sa level, a breakthrough curve representing the sea level change during the Holocone is obtained, in which, a sea level change caused by tectonic movement is subtracted. Two cycles of rise-drop of sea level with three periods of high sea level were found. The period with the highest sea level is some 6,000-5,000 years B.P.. According to the rise-drop rate of sea level, four periods of the sea level change can be distinguished in the Holocene. The amplitude of the sea flunctuation is about ± 6m over the past 6,000 years. [ABSTRACT FROM AUTHOR]

The evolution of Holocene climate was investigated using grain size and magnetic susceptibility of the Holocene paleosols from Baicaoyuan (BCY), Xifeng (XF) and Linyou (LY) sections in the northwest, central and southern Chinese Loess Plateau (CLP). The results show that the Holocene in the BCY, XF and LY paleosol sections could be divided into three phases: during the early Holocene (11.8–10.5 kyr B. P.), increased magnetic susceptibility (χ) and frequency-dependent magnetic susceptibility (χfd) and decreased median grain size (Md) indicate that the East Asian Summer Monsoon (EASM) has become more intense and the climate has changed from cold to warm. During the middle Holocene (10.5–5.0 kyr B. P.), the values of χ, χfd and 2–5 µm grain-size fraction (GT2/5) are higher and Md and 30–63 µm grain-size fraction (GT30/63) are the lowest, which reflect a warm and humid regional climate. At ∼ 8.0 kyr B. P., there was a transient dry-cold climatic spike corresponding to a Heinrich Event, the cold event was likely due to the collapse of the Laurentide ice sheet. During the late Holocene (5.0–0 kyr B. P.), χ and χfd values are the lowest, while Md and GT30/63 are high, as proxies of a weakened EASM, when the dry-cold climate prevailed in the region. Decreased irradiance since 5.0 kyr B.P. may have caused climatic cooling and drying. Spatially, the increased main peak values and skewness from BCY, XF to LY sections show that the grain size became fine, the East Asian Winter Monsoon (EAWM) reduced, and climate was warmer and wetter from northwest to southeast. In addition, Md can be used as alternative proxy for EAWM, while χfd is positive with the intensity of EASM under semiarid climate conditions in CLP. [ABSTRACT FROM AUTHOR]

In the mid-latitude regions of the Asian continent, Zhuye Lake is located in the northwest margin of the Asian monsoon, where the modern climate is affected by the Asian monsoon and Westerlies. In this study, we investigated the absolutely dated Holocene records in Zhuye Lake for detecting the Holocene climate cycles. Totally, 14 C dates and 6 optically simulated luminescence (OSL) dates are obtained from the QTH01 and QTH02 sections. The proxies of grain-size, total organic carbon content (TOC), C/N and δC are used for wavelet analysis, and the results show obvious ∼256, ∼512 and ∼1024-year climate cycles, which are consistent with the Holocene millennial and centennial scale climate cycles in the typical Asian summer monsoon domain. In different parts of the Zhuye Lake, the Holocene sediments show variable climate cycles that are affected by the lake basin topography. In the Zhuye Lake, the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events. [ABSTRACT FROM AUTHOR]

The upmost segment (Holocene series) of the Milanggouwan stratigraphic section (MGS1) in the Salawusu River valley shows 11 sedimentary cycles of dune sands and fluvio-lacustrine facies, or dune sands and paleosols. The analysis of the magnetic susceptibility of this segment suggests that there are 11 magnetic susceptibility cycles with the value alternating from low to high, in which the layers of the dune sands correspond to the lower value of the magnetic susceptibility and the layers of fluvio-lacustrine facies and paleosols correspond to the higher peaks. The study reveals that the low and high magnetic susceptibility values indicate the climate dominated by cold-arid winter monsoon and warm-humid summer monsoon of East Asia, respectively, and the study area has experienced at least 22 times of millennial-centennial scales climate alternation from the cold-arid to the warm-humid during the Holocene. In terms of the time and the climate nature, the variations basically correspond to those of the North Atlantic and some records of cold-warm changes in China as well. They might be caused by the alternation of winter and summer monsoons in the Mu Us Desert induced by global climate fluctuations in the Holocene. [ABSTRACT FROM AUTHOR]

Widespread aeolian sediments have been found in the middle reaches of the Yarlung Zangbo River, China. The grain-size characteristics of sediments from Cha’er Section in the area were analyzed. The results show that the section include one stratum of paleo-mobile dunes, four strata of paleo-semi-fixed dunes, two strata of paleo-fixed dunes, one stratum of sandy immature soils. The paleo-mobile and paleo-semi-fixed dune sand in this section are similar to modern aeolian sand in either grain-size composition or Mz and δ distribution. Compared the above types of dunes each other, the content of sand substance decreases, while the content of silt and clay increases for paleo-fixed dunes and sandy immature soils. Combined with age data for each stratum, the analysis shows that these strata are the products of climate changes and the evolution of aeolian landforms. The evolutionary sequence of the paleoclimate and of aeolian activities in the valley since 8600 yr B.P. reveals four stages: 8600–5700 yr B.P., when the paleoclimate was cold and dry, with strong winds, thereby activating dunes; 5700–3600 yr B.P., when it was warm and wet, with weak winds, causing dunes to undergo soil-forming processes; 3600–1900 yr B.P., when climate shifted from cold-dry with strong winds to warm-wet with weak winds, and activated dunes were fixed again; and 1900 yr B.P. -present, when the climate became fine, with weak winds, fixing dunes again. [ABSTRACT FROM AUTHOR]

By employing many methods including distinguishing the land-maps, interpreting the aerophotoes and Satellite-photographes, consulting historical documents, investigating ancient cultural relics, making investigations in the field, analysing the names and features of the place, and analysing the characteristics of the deposit, etc., a systematic study of the surface-emerging palaeochannels on the South Coast Plain of Laizhou Bay has been made. Twenty-five surface-emerging palacochannels were discovered and verified. According to the formation age, these palaeochannels were divided into two stages: six palaeochannels were formed in the Early and Middle Holocene, and nineteen palaeochannels were formed in the Late Holocene (the historical period). According to the landform features, the palaeochannels are divided into four categories: upland palaeochannel belts, strip-shaped upland palaeochannels, trough-shaped depression palaeochannels and ancient riverbeds. Among the four categories, the strip-shaped upland palaeochannels are the main types. The swinging and movement of the channels helped the alluvial plains expand and cause the coastal ancient lakes to vanish in succession. [ABSTRACT FROM AUTHOR]

A preliminary study on the advance and the retreat of Qingtu Lake and its climatic records of the Holocene lacustrine deposits has been made through comprehensive analysis. The study shows that the modes characteristics of climatic change in Eastern Hexi Corridor was provided with the corresponding relationship of warm-moist and cold-dry during the scale longer than hundred years. As a result of climatic changes and human activities, Qingtu-Lake cycle has undergone four lake-retreated and three lake-advanced stages since 6000 a B. P. Based on the study on lacustrine sedimentary color, grain size, Fe3+/Fe2+ and organic matter, the authors put forward that a warm period existed during the phase of 335–480 A. D. in the studied area. This warm period could be further testified by a lot of evidences obtained from the historical documents and the natural records of Qingtu Lake. In brief, the evolution of lakes in Eastern Hexi Corridor is characterized by sedimentary continuity, fast sedimentary rate and high resolution, it not only indicate the paleoenvironmental and climatic change in Holocene, but also can reflect the intensity of Eastern Asia monsoon. [ABSTRACT FROM AUTHOR]

Based on the δ13C and δ18O fluctuation of lacustrine carbonate, CaCO3 content and sporo-pollen data, a palaeoclimatic history of Bosten Lake during the Holocene has been outlined, several stages of climatic changes are divided, and the following result es are obtained: (1) Palaeoclimatic changes revealed by carbonate isotope around Bosten Lake are basically identical with that revealed by other geological records in Xinjiang. Environmental changes presented apparent Westlies Style model: during cold period, relative humidity increased, δ18O, δ13C and CaCO3 appeared low; but in warm periods, the dry regime aggravated. (2) The temperature reflected by δ18O exist evident features being increase in the late period during the Holocene. Together with the δ13C, pollen and CaCO3 analyses, several cold and warm phases which are of broad regional significance can be identified. The warm peaks occurred at about 11.0 ka B.P., 9.4 ka B.P., 7.5 ka B.P., 5.0 ka B.P., 3.0 ka B.P. and 2.0 ka B.P.; the cold peaks at 11.5 ka B.P., 10.5 ka B.P., 8.8 ka B.P., 5.5 ka B.P., 3.3 ka B.P., 2.2 ka B.P. and 1.5 ka B.P.. (3) Several climatic events with the nature of “abrupt climatic changes” are revealed in the periods of 11.0 ka B.P. −10.5 ka B.P., 9.4 ka B.P. −8.8 ka B.P., 5.5 ka B.P. −5.0 ka B.P. and 2.0 ka B.P. −1.5 ka B.P.. (4) The results show that carbonate isotopic record of lacustrine sediment in arid area is very sensitive to climatic changes, and may be play a very important role in understanding the features and mechanism of palaeoclimatic changes. [ABSTRACT FROM AUTHOR]

In this pater, the paleovegetation and paleoclimate in the Hemudu region of Zhejiang Province during 7000 to 6000 a B. P. are reconstructed. Firstly, using Andersen's method, a correction is made for the percentage of pollens of various plants excavated at Hemudu Site. Secondly, on the basis of the results, the dominant species and constructive species and types of zonal forest vegetation are identified, then the paleovegetation of Holocene Hypsithermal is reconstructed. Finally, by contrasting the above mentioned paleovegetation with the vegetation of Wuyanling Natural Reserve (WYLNR) in south Zhejiang and Dinghushan Natural Reserve (DHSNR) in Guangdong today, and on the analogy of above results, the paleoclimate is also reconstructed. [ABSTRACT FROM AUTHOR]