TY - JOUR A1 - Ashastina, Kseniia A1 - Kuzmina, Svetlana A1 - Rudaya, Natalia A1 - Troeva, Elena I. A1 - Schoch, Werner H. A1 - Roemermann, Christine A1 - Reinecke, Jennifer A1 - Otte, Volker A1 - Savvinov, Grigoriy A1 - Wesche, Karsten A1 - Kienast, Frank T1 - Woodlands and steppes BT - Pleistocene vegetation in Yakutia's most continental part recorded in the Batagay permafrost sequence JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - Based on fossil organism remains including plant macrofossils, charcoal, pollen, and invertebrates preserved in syngenetic deposits of the Batagay permafrost sequence in the Siberian Yana Highlands, we reconstructed the environmental history during marine isotope stages (MIS) 6 to 2. Two fossil assemblages, exceptionally rich in plant remains, allowed for a detailed description of the palaeo-vegetation during two climate extremes of the Late Pleistocene, the onset of the last glacial maximum (LGM) and the last interglacial. In addition, altogether 41 assemblages were used to outline the vegetation history since the penultimate cold stage of MIS 6. Accordingly, meadow steppes analogue to modern communities of the phytosociological order Festucetalia lenensis formed the primary vegetation during the Saalian and Weichselian cold stages. Cold-resistant tundra-steppe communities (Carici rupestris-Kobresietea bellardii) as they occur above the treeline today were, in contrast to more northern locations, mostly lacking. During the last interglacial, open coniferous woodland similar to modern larch taiga was the primary vegetation at the site. Abundant charcoal indicates wildfire events during the last interglacial. Zoogenic disturbances of the local vegetation were indicated by the presence of ruderal plants, especially by abundant Urtica dioica, suggesting that the area was an interglacial refugium for large herbivores. Meadow steppes, which formed the primary vegetation during cold stages and provided potentially suitable pastures for herbivores, were a significant constituent of the plant cover in the Yana Highlands also under the full warm stage conditions of the last interglacial. Consequently, meadow steppes occurred in the Yana Highlands during the entire investigated timespan from MIS 6 to MIS 2 documenting a remarkable environmental stability. Thus, the proportion of meadow steppe vegetation merely shifted in response to the respectively prevailing climatic conditions. Their persistence indicates low precipitation and a relatively warm growing season throughout and beyond the late Pleistocene. The studied fossil record also proves that modern steppe occurrences in the Yana Highlands did not establish as late as in the Holocene but instead are relicts of a formerly continuous steppe belt extending from Central Siberia to Northeast Yakutia during the Pleistocene. The persistence of plants and invertebrates characteristic of meadow steppe vegetation in interior Yakutia throughout the late Quaternary indicates climatic continuity and documents the suitability of this region as a refugium also for other organisms of the Pleistocene mammoth steppe including the iconic large herbivores. (C)2018 Elsevier Ltd. All rights reserved. KW - Palaeo-vegetation KW - Plant macrofossils KW - Invertebrates KW - Modern analogues KW - Pollen KW - Ground squirrel nest KW - Last cold stage KW - Eemian KW - Beringia Y1 - 2018 U6 - https://doi.org/10.1016/j.quascirev.2018.07.032 SN - 0277-3791 VL - 196 SP - 38 EP - 61 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Lenz, Josefine A1 - Grosse, Guido A1 - Jones, Benjamin M. A1 - Anthony, Katey M. Walter A1 - Bobrov, Anatoly A1 - Wulf, Sabine A1 - Wetterich, Sebastian T1 - Mid-Wisconsin to Holocene Permafrost and Landscape Dynamics based on a Drained Lake Basin Core from the Northern Seward Peninsula, Northwest Alaska JF - Permafrost and Periglacial Processes N2 - Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a4m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5ka BP. The latter was terminated by the deposition of 1m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42ka BP. Yedoma deposition continued until 22.5ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances. Copyright (c) 2015 John Wiley & Sons, Ltd. KW - Beringia KW - palaeoenvironmental reconstruction KW - thermokarst lake dynamics KW - cryostratigraphy KW - tephra KW - bioindicators KW - yedoma Y1 - 2016 U6 - https://doi.org/10.1002/ppp.1848 SN - 1045-6740 SN - 1099-1530 VL - 27 SP - 56 EP - 75 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Wetterich, Sebastian A1 - Rudaya, Natalia A1 - Kuznetsov, Vladislav A1 - Maksimov, Fedor A1 - Opel, Thomas A1 - Meyer, Hanno A1 - Günther, Frank A1 - Bobrov, Anatoly A1 - Raschke, Elena A1 - Zimmermann, Heike Hildegard A1 - Strauss, Jens A1 - Starikova, Anna A1 - Fuchs, Margret A1 - Schirrmeister, Lutz T1 - Ice Complex formation on Bol'shoy Lyakhovsky Island (New Siberian Archipelago, East Siberian Arctic) since about 200 ka JF - Quaternary research : an interdisciplinary journal N2 - Late Quaternary landscapes of unglaciated Beringia were largely shaped by ice-wedge polygon tundra. Ice Complex (IC) strata preserve such ancient polygon formations. Here we report on the Yukagir IC from Bol'shoy Lyakhovsky Island in northeastern Siberia and suggest that new radioisotope disequilibria (230Th/U) dates of the Yukagir IC peat confirm its formation during the Marine Oxygen Isotope Stage (MIS) 7a–c interglacial period. The preservation of the ice-rich Yukagir IC proves its resilience to last interglacial and late glacial–Holocene warming. This study compares the Yukagir IC to IC strata of MIS 5, MIS 3, and MIS 2 ages exposed on Bol'shoy Lyakhovsky Island. Besides high intrasedimental ice content and syngenetic ice wedges intersecting silts, sandy silts, the Yukagir IC is characterized by high organic matter (OM) accumulation and low OM decomposition of a distinctive Drepanocladus moss-peat. The Yukagir IC pollen data reveal grass-shrub-moss tundra indicating rather wet summer conditions similar to modern ones. The stable isotope composition of Yukagir IC wedge ice is similar to those of the MIS 5 and MIS 3 ICs pointing to similar atmospheric moisture generation and transport patterns in winter. IC data from glacial and interglacial periods provide insights into permafrost and climate dynamics since about 200 ka. KW - Cryostratigraphy KW - Ice wedges KW - Stable isotopes KW - Pollen KW - Radioisotope disequilibria dating KW - Beringia Y1 - 2019 U6 - https://doi.org/10.1017/qua.2019.6 SN - 0033-5894 SN - 1096-0287 VL - 92 IS - 2 SP - 530 EP - 548 PB - Cambridge Univ. Press CY - New York ER -