scholarly journals Early Holocene permafrost retreat in West Siberia amplified by reorganization of westerly wind systems

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ting-Yong Li ◽  
Jonathan L. Baker ◽  
Tao Wang ◽  
Jian Zhang ◽  
Yao Wu ◽  
...  
Keyword(s):  
Younger Dryas ◽  
West Siberia ◽  
Early Holocene ◽  
Northern Eurasia ◽  
Permafrost Degradation ◽  
Westerly Wind ◽  
Altai Mountains ◽  
Before Present ◽  
Climate Anomaly ◽  
Southwestern Siberia

AbstractRapid permafrost degradation and peatland expansion occurred in Eurasia during the Early Holocene and may be analogous to the region’s response to anthropogenic warming. Here we present a 230Th-dated, multiproxy speleothem record with subdecadal sampling resolution from Kyok-Tash Cave, at the modern permafrost margin in the northern Altai Mountains, southwestern Siberia. Stalagmite K4, covering the period 11,400 to 8,900 years before present, indicates an absence of stable permafrost within three centuries of the Younger Dryas termination. Between 11,400 and 10,400 years ago, speleothem δ18O is antiphased between the Altai and Ural ranges, suggesting a reorganization of the westerly wind systems that led to warmer and wetter winters over West Siberia and Altai, relative to the zonally adjacent regions of Northern Eurasia. At the same time, there is evidence of peak permafrost degradation and peatland expansion in West Siberia, consistent with the interpreted climate anomaly. Based on these findings, we suggest that modern permafrost in Eurasia is sensitive to feedbacks in the ocean-cryosphere system, which are projected to alter circulation regimes over the continent.

Recurrent outburst floods and explosive volcanism during the Younger Dryas–Early Holocene deglaciation in south Iceland: evidence from a lacustrine record

2021 ◽  
Author(s):  
Áslaug Geirsdóttir ◽  
Gifford H. Miller ◽  
David J. Harning ◽  
Hrafnhildur Hannesdóttir ◽  
Thor Thordarson ◽  
...  
Keyword(s):  
Younger Dryas ◽  
Explosive Volcanism ◽  
Early Holocene ◽  
Outburst Floods

scholarly journals Millennial‐scale deglaciation across the European Alps at the transition between the Younger Dryas and the Early Holocene – evidence from a new cosmogenic nuclide chronology

Boreas ◽  
2021 ◽  
Author(s):  
Marie Protin ◽  
Irene Schimmelpfennig ◽  
Jean‐Louis Mugnier ◽  
Jean‐François Buoncristiani ◽  
Melaine Le Roy ◽  
...  
Keyword(s):  
Younger Dryas ◽  
Early Holocene ◽  
European Alps ◽  
Cosmogenic Nuclide ◽  
Millennial Scale

A multiproxy record of sedimentation, pedogenesis, and environmental history in the north of West Siberia during the late Pleistocene based on the Belaya Gora section

2020 ◽  
pp. 1-19
Author(s):  
Vladimir Sheinkman ◽  
Sergey Sedov ◽  
Lyudmila S. Shumilovskikh ◽  
Elena Bezrukova ◽  
Dmitriy Dobrynin ◽  
...  
Keyword(s):  
Environmental History ◽  
Boreal Forests ◽  
West Siberia ◽  
Northern Eurasia ◽  
Partial Recovery ◽  
Radiocarbon Dates ◽  
Oxygen Isotope Stage ◽  
Mis 3 ◽  
The North ◽  
Mis 5

Abstract Recent revision of the Pleistocene glaciation boundaries in northern Eurasia has encouraged the search for nonglacial geological records of the environmental history of northern West Siberia. We studied an alluvial paleosol-sedimentary sequence of the high terrace of the Vakh River (middle Ob basin) to extract the indicators of environmental change since Marine Oxygen Isotope Stage (MIS) 6. Two levels of the buried paleosols are attributed to MIS 5 and MIS 3, as evidenced by U/Th and radiocarbon dates. Palynological and pedogenetic characteristics of the lower pedocomplex recorded the climate fluctuations during MIS 5, from the Picea-Larix taiga environment during MIS 5e to the establishment of the tundra-steppe environment due to the cooling of MIS 5d or MIS 5b and partial recovery of boreal forests with Picea and Pinus in MIS 5c or MIS 5a. The upper paleosol level shows signs of cryogenic hydromorphic pedogenesis corresponding to the tundra landscape, with permafrost during MIS 3. Boulders incorporated in a laminated alluvial deposit between the paleosols are dropstones brought from the Enisei valley by ice rafting during the cold MIS 4. An abundance of eolian morphostructures on quartz grains from the sediments that overly the upper paleosol suggests a cold, dry, and windy environment during the MIS 2 cryochron.

The Peopling of the Baraba Forest-Steppe in the Neolithic: Cranial Evidence

2021 ◽  
Vol 49 (1) ◽  
pp. 133-146
Author(s):  
T. A. Chikisheva ◽  
D. V. Pozdnyakov
Keyword(s):  
Local Population ◽  
Principal Component ◽  
Early Holocene ◽  
Russian Plain ◽  
Northern Eurasia ◽  
Forest Steppe ◽  
Early Neolithic ◽  
Population Continuity ◽  
Lake Systems

On the basis of statistical analysis of craniometric data relating to Mesolithic and Neolithic samples from northern Eurasia, we discuss the peopling of the Baraba forest-steppe in the Early Holocene. This region is represented by samples from Sopka-2/1 (early sixth millennium BC), Protoka (late fifth to early fourth millennia BC), Korchugan (early-mid sixth millennium BC), and Vengerovo-2A (late sixth millennium BC). The results of the principal component analysis are interpreted in the context of debates over the role of autochthonous traditions in the Neolithic. During the Preboreal period (10 ka BP), large parts of the Baraba forest-steppe were flooded by the transgression of lake systems during climatic warming. This may have caused depopulation, lasting for at least a millennium. The Early Holocene people of Baraba were an offshoot of Meso-Neolithic populations of the northwestern Russian Plain. On that basis, the Early Neolithic populations of Baraba were formed. Direct population continuity is traceable only through the Chalcolithic. Since the late sixth millennium BC, however, the local population had incorporated migrants from the Pit-Comb Ware area in the central Russian Plain and, indirectly (via the Neolithic Altai), from the Cis-Baikal area.

scholarly journals How dry was the Younger Dryas? Evidence from a coupled <i>δ</i><sup>2</sup>H–<i>δ</i><sup>18</sup>O biomarker paleohygrometer applied to the Gemündener Maar sediments, Western Eifel, Germany

2019 ◽  
Vol 15 (2) ◽  
pp. 713-733 ◽  
Author(s):  
Johannes Hepp ◽  
Lorenz Wüthrich ◽  
Tobias Bromm ◽  
Marcel Bliedtner ◽  
Imke Kathrin Schäfer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Younger Dryas ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Leaf Water ◽  
Early Holocene ◽  
Unexpected Finding ◽  
Temperature Dependent ◽  
The Past ◽  
Natural Climate

Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.

scholarly journals Revisions and Extension of the Hohenheim Oak and Pine Chronologies: New Evidence About the Timing of the Younger Dryas/Preboreal Transition

Radiocarbon ◽  
1998 ◽  
Vol 40 (3) ◽  
pp. 1107-1116 ◽  
Author(s):  
Marco Spurk ◽  
Michael Friedrich ◽  
Jutta Hofmann ◽  
Sabine Remmele ◽  
Burkhard Frenzel ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Younger Dryas ◽  
Ice Cores ◽  
Early Holocene ◽  
Proxy Data ◽  
The Past ◽  
Varve Chronology ◽  
New Evidence ◽  
Radiocarbon Calibration

Oak and pine samples housed at the Institute of Botany, University of Hohenheim, are the backbone of the early Holocene part of the radiocarbon calibration curve, published in 1993 (Becker 1993; Kromer and Becker 1993; Stuiver and Becker 1993; Vogel et al. 1993). Since then the chronologies have been revised. The revisions include 1) the discovery of 41 missing years in the oak chronology and 2) a shift of 54 yr for the oldest part back into the past. The oak chronology was also extended with new samples as far back as 10,429 BP (8480 BC). In addition, the formerly tentatively dated pine chronology (Becker 1993) has been rebuilt and shifted to an earlier date. It is now positioned by 14C matching at 11,871-9900 BP (9922–7951 BC) with an uncertainty of ±20 yr (Kromer and Spurk 1998). With these new chronologies the 14C calibration curve can now be corrected, eliminating the discrepancy in the dating of the Younger Dryas/Preboreal transition between the proxy data of the GRIP and GISP ice cores (Johnsen et al. 1992; Taylor et al. 1993), the varve chronology of Lake Gościąż (Goslar et al. 1995) and the pine chronology (Becker, Kromer and Trimborn 1991).

scholarly journals A major hydrobiological change in Dasht-e Arjan Wetland (southwestern Iran) during the late glacial – early Holocene transition revealed by subfossil chironomids

2019 ◽  
Vol 56 (8) ◽  
pp. 848-856
Author(s):  
Cyril Aubert ◽  
Morteza Djamali ◽  
Matthew Jones ◽  
Hamid Lahijani ◽  
Nick Marriner ◽  
...  
Keyword(s):  
Lake Level ◽  
Regional Scale ◽  
Younger Dryas ◽  
Late Glacial ◽  
Early Holocene ◽  
Geochemical Data ◽  
The Holocene ◽  
Chironomus Plumosus ◽  
Subfossil Chironomids ◽  
Southwestern Iran

The late glacial – early Holocene transition is a key period in the earth’s history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (southwestern Iran, near to Persepolis) during the late glacial – early Holocene transition (ca. 11 650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene, a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type, and Glyptotendipes pallens-type, suggests a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in Northern Hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the Younger Dryas highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the meltwater inflow from small local glaciers in the catchment basin is not excluded.

scholarly journals Recent glacier variations in Mongolia

2007 ◽  
Vol 46 ◽  
pp. 185-188 ◽  
Author(s):  
Kadota Tsutomu ◽  
Davaa Gombo
Keyword(s):  
Global Warming ◽  
Satellite Images ◽  
Monitoring Network ◽  
Aerial Photographs ◽  
Northern Eurasia ◽  
High Mountain ◽  
Altai Mountains ◽  
Mountain Regions ◽  
Significant Change ◽  
Topographical Maps

AbstractGlacier monitoring enables us to detect influences of global warming in high mountain regions. To initiate the establishment of a glacier-monitoring network in northern Eurasia, we studied recent glacier variations in Mongolia using topographical maps, aerial photographs and satellite images (Corona and Landsat). Glaciers in Mongolia exist in the Altai mountains which span approximately 1400 km within Russia, China and Mongolia. Four regions were selected to form the study area: Tavan Bogd region, Turgen massif, Kharkhiraa massif and Tsambagarav massif. During the period from the 1940s to 2000 or from 1968 to 2000, the glaciers in these regions lost 10.2%, 19.3%, 28.0% and 28.8% of their area respectively. The glaciers in the Tavan Bogd, Kharkhiraa and Turgen regions were found to have been almost stationary since 1987/88, while those in Tsambagarav massif showed no significant change in area since 1963. Shrinkage of the glaciers occurred between 1945/68 and 1987/88 in the former regions and between 1948 and 1963 in the latter. Mongolian glaciers seem to behave differently from other glaciers which have been experiencing steady shrinkage recently.

scholarly journals River of Change: a Model for the Development of Terraces Along the Bow River, Alberta

2004 ◽  
Vol 56 (2-3) ◽  
pp. 155-169 ◽  
Author(s):  
Gerald A. Oetelaar
Keyword(s):  
Late Pleistocene ◽  
Rocky Mountains ◽  
Sediment Load ◽  
Younger Dryas ◽  
Early Holocene ◽  
Stream Power ◽  
Independent Variables ◽  
The Past ◽  
Initial Episode ◽  
Alluvial Terraces

Abstract Researchers working in the Bow River valley have identified a minimum of four alluvial terraces, the upper two of which have been designated as paired terraces. Over the past 35 years, they have attempted to correlate these alluvial landforms and to generate models for the development of the terraces along the section of the Bow River between Calgary and the Rocky Mountains. In this study, Mazama ash and an early Holocene paleosol are used to correlate the terrace suites examined by previous researchers and to generate a model which accounts for the development of the upper two sets of paired terraces. These paired terraces reflect major episodes of aggradation and degradation that result from changes in independent variables such as climate and uplift. The initial episode of aggradation, dating from the late Pleistocene, is the result of paraglacial processes in a sparsely vegetated, yet saturated environment. Following a brief episode of degradation at the end of the Younger Dryas, the second episode of aggradation, dating from 9000 to 5000 BP, is caused by increased sediment load and lowered stream power during the Hypsithermal.

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