The North of Eastern Siberia: Refuge of Mammoth Fauna in the Holocene

The global climate changings at the end of Pleistocene led to extinction of the typical representatives of Mammoth fauna–mammoth, woolly rhinoceros, wild horse, bison, muskox, cave lion, etc.–on the huge territories of Northern Eurasia. Undoubtedly the Mammoth fauna underwent pressure from the Upper Paleolithic Man, whose hunting activity also could play the role in decreasing the number of mammoths and other representatives of megafauna (large mammals). Archaeological data testify that the typical representatives of Mammoth fauna were the Man's hunting objects only till the end of the Pleistocene. Their bone remains are not usually found on the settlements of Mesolithic Man. Formerly it was supposed that the megafauna of ‘Mammoth complex’ was extinct by the beginning of Holocene. Nevertheless the latest data testify that the global extinction of the Mammoth fauna was sufficiently delayed in the north of Eastern Siberia. In the 1990s some radiocarbon data testified that the mammoths on the Wrangel Island existed for a long time during the Holocene from 8000 till 3700 y. BP. The present radiocarbon data show that wild horses inhabited the north of Eastern Siberia (the lower stream of the Enissey river, the Novosibirskie Islands, the East Siberian sea-shore) 3000–2000 y. BP. Musk-oxen lived on the Taimyr Peninsula and the Lena River delta about 3000 y. BP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the process of preservation of the Mammoth fauna representatives. The cool and dry climate of this region promotes the maintenance of steppe associations – habitats of those mammals. The Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from the Taimyr Peninsula to a lower stream of the Yana River; they are very rare in the basins of the Indigirka and Kolyma Rivers. So, the small number of the Stone Age hunting tribes on the North of Eastern Siberia was another factor in the long-term preservation of some Mammoth fauna representatives.     

Evidence of reworking and resuspension of carbonates during last glacial maximum and early deglacial period along the southwest coast of India

A gravity core collected from the upper slope of southwest of Quilon at a water depth of 776 m (Lat: 8°12′263″N, Long: 76°28′281″E) was analysed for texture (carbonate free), calcium carbonate and organic carbon. Variation in silicic fraction seems to be controlled by silt, i.e., enrichment from 15 ka BP to 10 ka BP and then constant in Holocene. Below 15 ka BP, the silicic fraction gets depleted compared to the Holocene section with a minimum around 21 ka BP. Clay content remains nearly constant except in the Holocene where it shows an enrichment. Carbonate content of less than 63 micron when computed by subtracting coarse fraction content from the total carbonate suggests that the total carbonates are mainly concentrated in the finer fraction. All these carbonate phases show an inverse relationship with silicic fraction except in Holocene. Below 15 ka BP, CaCO₃ dominates in sediments comprising more than 65%, such an increase is also seen in the coarse fraction. Coarse fraction from these sections contains abundant nodular type aggregates encrusting small forams. This period is marked by a high sedimentation rate comparable to Holocene. These parameters suggest that the productivity and precipitation have increased in the Holocene due to the intensification of the southwest monsoon. During the last glacial maximum and early deglacial period the high sedimentation rate indicates redeposition of the carbonates from the existing carbonate lithofacies situated between Quilon and Cape Comorin probably due to the slope instability.     

Multiproxy evidence of an early Holocene (8.2 kyr) climate oscillation in central Nova Scotia,Canada

An early Holocene lake sediment record from central Nova Scotia contains a minerogenic oscillation that is closely correlative with the 8.2 kyr event (ca. 8200 cal. yr BP), an event that has not been reported elsewhere in Atlantic Canada. A variety of biological and sedimentological indicators have been examined to characterise autochthonous and allochthonous changes that occurred during this time. The minerogenic upper oscillation (UO, ca. 8400 cal. yr BP) is marked by an increase in the chrysophyte:diatom ratio. Following the oscillation, the diatom community reflects a shift to more productive, less acidic conditions. The pollen record shows no major response to this short‐lived event. Lithostratigraphic analyses indicates that the UO is characterised by an increase in clastic content, magnetic susceptibility and mean sediment grain size, all indicators of changing environmental conditions, most likely the result of regional cooling. The Taylor Lake record adds to a growing body of evidence for a widespread, hemispheric climate oscillation at 8.2 kyr. Copyright © 2002 John Wiley & Sons, Ltd.     

Sedimentologic and palynologic records of the last deglaciation and Holocene from Ballston Lake, New York

Continuous pollen and sediment records from two ∼8.5-m-long cores document late Pleistocene and Holocene sedimentation and vegetation change in the Ballston Lake basin, eastern New York State. Pebbles at the base of both cores and the geomorphology of the watershed reflect the presence of the Mohawk River in the basin prior to ∼12,900 ± 70 cal yr B.P. Ballston Lake formed at the onset of the Younger Dryas (YD) by an avulsion of the Mohawk River. The transition from clay to gyttja with low magnetic susceptibility (MS), low bulk density, and high organic carbon indicates rapid warming and increased lake productivity beginning 11,020 cal yr B.P. MS measurements reveal that the influx of magnetic particles, associated with pre-Holocene clastic sedimentation, ceased after ∼10,780 cal yr B.P. The pollen record is subdivided into six zones: BL1 (12,920 to 11,020 cal yr B.P.) is dominated by boreal forest pollen; BL2 (11,020 to 10,780 cal yr B.P.) by pine (Pinus) forest pollen; BL3 (10,780 to 5290 cal yr B.P.) by hemlock (Tsuga) and mixed hardwood pollen; BL4 (5290 to 2680 cal yr B.P.) by mixed hardwood pollen; BL5a (2680 cal yr B.P. to 1030 cal yr B.P.) by conifer and mixed hardwood pollen; and BL5b (1030 cal B.P. to present) by increasing ragweed (Ambrosia) pollen. A 62% decrease in spruce (Picea) pollen in <320 cal years during BL1 reflects rapid warming at the end of the YD. Holocene pollen zones record more subtle climatic shifts than occurred at the end of the YD. One of the largest changes in the Holocene pollen spectra began ∼5300 cal yr B.P., and is characterized by a marked decline in hemlock pollen. This has been noted in other pollen records from the region and may record preferential selection of hemlock by a pathogen or parasites.     

Stable oxygen isotope and pollen records from eastern Scotland and a consideration of Late-glacial and early Holocene climate change for Europe

The presence of marl deposits belonging to the Lateglacial period in a former lake basin at Lundin Tower in Fife, Scotland has allowed palaeoenvironmental investigations by means of carbonate δ¹³C and δ¹⁸O, and organic matter δ¹³C, in addition to palynology. The variations that emerge reveal strong similarities between the pollen and isotope records and these are interpreted as reflecting climatic shifts. The classic Late-glacial pattern of Oldest Dryas–Bølling–Older Dryas–Allerød–Younger Dryas may be evident and other climatic oscillations are shown to have occurred not only during the Allerød but also in the Preboreal. The problem of the time discordance between isotopic change and pollen representation is addressed through explanations involving lags in plant colonization. A comparison of the δ¹⁸O records from 43 sites across Europe reveals two different regional patterns, which raises fundamental questions over the nature of Late-glacial palaeoclimates.     

The role of climate variability and fire in early and mid Holocene forest dynamics of southern Sweden

The objective of this study was to investigate the possible links between regional climate, fire and vegetation at the small spatial scale during the early and mid Holocene in southern Sweden using pollen, plant macrofossil and charcoal records from a small bog. The fire history was compared with climate reconstructions inferred from various proxy records in the study region. High fire activity is related to dry and warm climate around 8550, 7600, 5500–5100 and 4500 cal. a BC. Low fire activity ca. 6500–6000 and 4750 BC may correspond to the widespread ‘8.2 k event’ (ca. 6200 BC) recorded across the North Atlantic region, and a later, brief period of increased precipitation, respectively. The decrease in broadleaved trees culminating ca. 6500–6000 BC correlates with the ‘8.2 k event’. A long mid Holocene period with low fire activity (ca. 4350–1000 BC) agrees with the pattern emerging for Europe from the global charcoal database, and may correspond to generally wetter and cooler conditions. High fire activity ca. 8550 BC probably triggered the local establishment of Corylus. Warmer and drier conditions (and high fire activity) ca. 7600 BC might have favoured the establishment of Alnus, Quercus and Tilia. The fire‐adapted Pinus maintained important populations throughout the early and mid Holocene. Copyright © 2008 John Wiley & Sons, Ltd.     

Cave bear occupation in Schwabenreith Cave,Austria, during the early last glacial: constraints from 230Th/U‐dated speleothems

The cave bear was a prominent member of the Upper Pleistocene fauna in Eurasia. While breakthroughs were recently achieved with respect to its phylogeny using ancient DNA techniques, it is still challenging to date cave bear fossils beyond the radiocarbon age range. Without an accurate and precise chronological framework, however, key questions regarding the palaeoecology cannot be addressed, such as the extent to which large climate swings during the last glacial affected the habitat and possibly even conditioned the final extinction of this mammal. Key to constraining the age of cave bear fossils older than the lower limit of radiocarbon dating is to date interlayered speleothems using ²³⁰Th/U. Here we report new results from one such site in the Eastern European Alps (Schwabenreith Cave), which yielded the highest density of bones of cave bear (Ursus spelaeus eremus). Although dating of the flowstones overlying this fossiliferous succession was partly compromised by diagenetic alteration, the ²³⁰Th/U dates indicate that the bear hibernated in this cave after about 113 ka and before about 109 ka. This time interval coincides with the equivalent of Greenland Stadial 25, suggesting possible climate control on the cave bear's habitat and behaviour. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd     

中国全新世分区气温序列集成重建及特征分析*

按照气温变化规律将中国气温变化划分为东北、华北北部、华东华南、华南、陕甘宁、川黔桂、新疆和滇藏高原区等8个分区。搜集有确切年代和气温数值的古气温记录1397条,以8个分区为单元进行整理,以日历年时间为坐标系,采用单样本区域订正—多样本平均集成法重建了东北、华北北部、华东华南、华南和滇藏高原区的全新世200 a分辨率连续集成气温序列。结果表明：5条分区连续气温序列与所在区域的高分辨率环境记录变化趋势基本一致,主要的百年尺度冷暖事件有较高的可比性;5条分区连续序列指示全新世气温变化可以分为明显的早期升温、中期大暖期和晚期变冷3个阶段;气温变化幅度区域差异较大,但主要的冷暖事件基本一致,暖期盛期发生在8～6ka BP,当时滇藏高原约比现代高2℃,东北高出3℃,华北北部高1.5℃,华东华南接近1℃,华南区仅高出0.5℃;主要冷事件发生在9.2、6.2、4.0和0.4 ka BP,其中,4.0 ka BP冷事件规模较大,滇藏高原、东北、华北北部、华东华南和华南区降低幅度分别为1.5、2、1、0.5和0.5℃。全新世期间各分区气温变化幅度也表现出纬度从北向南、海拔从高到低、气温变化幅度依次递减的特征。     

Lateglacial and early Holocene dynamics of adjacent valley glaciers in the Western Swiss Alps

The Alps play a pivotal role for glacier and climate reconstructions within Europe. Detailed glacial chronologies provide important insights into mechanisms of glaciation and climate change. We present 26 ¹⁰Be exposure dates of glacially transported boulders situated on moraines and ice‐moulded bedrock samples at the Belalp cirque and the Great Aletsch valley, Switzerland. Weighted mean ages of ～10.9, 11.1, 11.0 and 9.6 ka for the Belalp, on up to six individual moraine ridges, constrain these moraines to the Egesen, Kartell and Schams stadials during Lateglacial to early Holocene times. The weighted mean age of ～12.5 ka for the right‐lateral moraine of the Great Aletsch correlates with the Egesen stadial related to the Younger Dryas cooling. These data indicate that during the early Holocene between ～11.7 and ～9.2 ka, glaciers in the Swiss Alps seem to have been significantly affected by cold climatic conditions initiated during the Younger Dryas and the Preboreal Oscillation. These conditions resulted in glacier margin oscillations relating to climatic fluctuations during the second phase of the Younger Dryas – and continuing into Boreal times – as supported by correlation of the innermost moraine of the Belalp Cirque to the Schams (early) Holocene stage. Copyright © 2011 John Wiley & Sons, Ltd.     

13 ka以来东亚夏季风演变过程和全新世适宜期问题

基于湖北神农架三宝洞石笋SB43的21个230Th年龄和486个氧同位素数据,建立了13．0-0．2ka时段东亚夏季风强度演化序列,其长期演化趋势与33°N太阳辐射变化基本一致。通过对比三宝洞、董歌洞、阿曼Qunf洞及和尚洞石笋δ18O记录,发现东亚和印度季风强度在轨道尺度上呈同相位变化。石笋SB43、D4 δ18O值与Cariaco盆地Ti含量曲线整体变化一致,相关系数高达0．8,表明热带辐合带（ITCZ）的南北移动可能对亚洲中低纬季风强度起放大作用;全新世适宜期在亚洲季风区不存在显著穿时性,起止时间大体一致,约为10．2～5．7ka。早、中全新世季风强度与极地温度变化趋势一致,相关系数高达0．9,表明当时高纬冰量边界条件可能对亚洲季风强度变化（包括ITCZ的平均位置）具有贡献作用。     

Glacier Relics of the Last Glacial and Holocene Periods Discovered in the Middle‐low Mountains of Eastern China: Sedimentary Sequences and Environmental Evolution of Mengshan Mountain in Shandong Province since 80 ka

The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Taihang Mountainin eastern China. In 1947, he published his research findings in the magazine Mount Lushan in Glacial Age. The research results had established three Ice Ages: Poyang(Gonzi), Dagu(Minde), and Lushan(Lisi). However, at that time, no Wurm glacial relics of the last Ice Ag...     

Response of testate amoeba assemblages to environmental and climatic changes during the Lateglacial–Holocene transition at Lake Lautrey (Jura Mountains,eastern France)

We tested the response of lacustrine testate amoebae (thecamoebians) to climate and environmental changes for the Lateglacial–Holocene transition. The palaeoenvironmental history of the study site (Lake Lautrey, Jura Mountains, eastern France) was previously established based on high‐resolution multi‐proxy studies of the same core. The present study is characterised by a high taxonomic resolution (54 taxa), inclusion of small species (down to 25 µm) and high total counts (>500 individuals per sample on average). Changes in the composition of testate amoeba assemblages (dominant species and assemblage structure), as well as in the accumulation rate (tests cm^?2 a^?1), corresponded to major climatic phases (i.e. Oldest Dryas, Bølling–Allerød Interstadial, Younger Dryas, Preboreal) as well as changes in organic matter inputs. Furthermore, decreases in the accumulation rate characterised minor short‐lived cooling events, such as Older Dryas event or Gerzensee oscillation. However, the Preboreal oscillation, which was well registered by other proxies at Lake Lautrey, could not be recognised in the testate amoeba record. This work demonstrates that lacustrine testate amoebae can be used for palaeoclimatic and palaeoecological reconstructions. Nevertheless, a better understanding of the relation between climate, organic matter and lacustrine testate amoebae requires further high‐resolution studies based on multi‐proxy approaches and the development of appropriate modern analogues. Copyright © 2010 John Wiley & Sons, Ltd.     

High-resolution evidence from southern China of an early Holocene optimum and a mid-Holocene dry event during the past 18,000 years

Computer models suggest that the Holocene Optimum for East Asian summer monsoon precipitation occurred at different times in different regions of China. Previous studies indicate that this time-transgressive Holocene Optimum should have been experienced about 3000 yr ago in southern China. In this study we describe a section which allows us to test this timing directly. We have closely examined high-resolution eutrophic peat/mud sequences covering the past 18,000 cal yr at Dahu, Jiangxi, on the southern boundary of the mid subtropical zone in China. Late Pleistocene successions in the Dahu record indicate cooler and much wetter conditions relative to synchronous events in north-central China. Our results indicate that the Holocene Optimum occurred between ca. 10,000 and 6000 cal yr ago in southern China, consistent with the global pattern. Conditions were relatively dry and cold from 6000 to 4000 cal yr ago. Our data also support the conclusion that the last deglaciation to early Holocene in the south was much wetter, resulting in the formation of dense broad-leaved forests, which could have acted to moderate land temperature ∼10,000 to 6000 cal yr ago, yielding a stable early-Holocene climate. After 6000 cal yr, forest reduction led to unstable land temperatures, and possibly to a northerly shift of the subtropical high-pressure system. Whatever the mechanism, these changes resulted in decreased precipitation between 6000 and 4000 cal yr B.P. in southern China.     

Fire and drought as drivers of early Holocene tree line changes in the Peruvian Andes

Three pollen and charcoal records from three lakes lying at 3400 m elevation in southern Peru provided a record of landscape change spanning the last ca.18 000 cal. a BP. The tree line lay close to the site between ca. 16 000 and 12 000 cal. a BP, with Polylepis woodlands growing near the lakes. Progressively drying conditions led to increased fire after 12 000 cal. a BP, coinciding with a decline in Polylepis cover and Andean forest relicts as puna grasslands expanded. A strong decrease in the rate of sediment deposition between ca. 12 000 and ca. 4400 cal. a BP was interpreted to indicate the presence of sedimentary hiatuses. With the return of wet conditions after 4400 cal. a BP, forests did not reassemble around the lakes. Instead, fire‐maintained grasslands dominated the landscape. Humans probably induced the intensified fire activity during the late Holocene and thereby deflected local successions. The modern fragmented landscape, with Polylepsis woodlands existing in fire‐resistant pockets above the general limit of the Andean tree line, resulted from the intensification of human land use practices during the last 4400 cal. a BP. Copyright © 2011 John Wiley & Sons, Ltd.     

中国全新世人群两性身高差异演变初析

两性身高差异对了解同一人群内两性间体质、生存策略及食谱构成等方面的异同具有重要意义。目前, 中国全新世人群两性身高差异的分布状况及其演变过程尚不明确。本研究收集51组古代人群股骨最大长数据, 选取合适公式重建各人群的男、女平均身高并计算不同时代人群的两性身高差异指数, 探析中国古代人群两性身高差异的演变特征。结果显示: 两性股骨最大长差异在新石器至铁器阶段呈增大趋势; 男、女平均身高在新石器至青铜阶段显著降低, 但在青铜至铁器阶段无明显变化; 两性身高差异从新石器至青铜阶段显著增大, 但在青铜至铁器阶段无明显变化。在新石器至青铜阶段, 中国人群两性平均身高的降低可能与生存压力的增大和下肢功能性需求的降低密切相关; 两性身高差异的增大表明女性平均身高下降程度要大于男性, 这可能与两性分工的强化和食物精细化有关。

     

A continuous Holocene beetle record from the site Stavsåkra,southern Sweden: implications for the last 10 600 years of forest and land use history

Beetle remains from a small bog in southern Sweden contribute information concerning the forest history of the study area. The study shows that beetles are valuable indicators of woodland structures such as openness, field vegetation, presence of dead wood and disturbance factors such as climate change, fire regimes, grazing and land use. The early Holocene, ca. 8600–6450 cal. BC, was characterised by open, pine‐dominated woodlands maintained by fire and grazing disturbances. The changes in the wetland fauna, between 8600 and 7500 cal. BC, correlate well with low lake levels in southern Sweden. During the mid Holocene, ca. 6450–2400 cal. BC, the woodlands were relatively dense, with few openings in the canopy. Around 4200 cal. BC, there was a shift to a dominance of deciduous trees. Fire and grazing pressures were particularly low. Numbers of aquatic and hygrophilic beetles indicate dry conditions between ca. 5000 and 3000 cal. BC. During the late Holocene, ca. 2400 cal. BC to present, the woodlands opened up mainly through increased land use. The main disturbance factors were fire and grazing. The beetles indicate the formation of heather‐dominated heathland around 800 cal. BC. Copyright © 2008 John Wiley & Sons, Ltd. This article was published online on 23 December 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected (5 August 2009).