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Since 1994, permafrost deposits of the Siberian Yedoma region have been in the focus of the joint Russian-German scientific cooperation in terrestrial Polar research (Figure 1). These studies focused on cryostratigraphic, geochemical, geochronological, and paleontological characteristics at more than 25 individual study sites of the late Pleistocene Yedoma Ice Complex in Siberia and provided a detailed insight into the paleoenvironments and paleoclimate for the westernmost part of Beringia. The multidisciplinary investigations resulted in new ideas and discussions in the ongoing scientific debate on the origin of Yedoma Ice Complex and the main periglacial processes involved in its formation (1,2,3). The Yedoma Ice Complex is an ice-rich type of permafrost deposit widely distributed across Beringia. The Ice Complex aggradation is mainly controlled by the growth of syngenetic ice wedge polygons contributing up to 60 vol% of the entire formation. The clastic sedimentation of ice-oversaturated Yedoma deposits with considerable organic matter content is further controlled by local conditions such as source rocks and periglacial weathering processes, paleotopography, and temporary surface stabilization with autochthonous peat growth and soil formation. Key processes include alluvial, fluvial, and niveo-aeolian transport (4) as well as accumulation in ponding waters and continued in-situ frost weathering over millennial time-scales. Important post-depositional processes affecting Yedoma deposits are solifluction, cryoturbation, and pedogenesis. Major joint Russian-German field studies were conducted on Taymyr Peninsula (5,6,7,8,9,10,11), along the western and central Laptev Sea coasts (12,13,14,15,16,17,18), in the Lena Delta (19,20,21,22), on islands of the New Siberian Archipelago (23,24,25,26,27,28), and the adjacent mainland (29). Further study sites were conducted in the Kolyma Lowland (30), the Yana Highlands (31,32), in the foothills of the Verkhoyan Mountains (33,34,35,36), and in Central Yakutia (37). Comprehensive sampling and further analytical work included not only the Yedoma Ice Complex itself but also included its stratigraphic context of older underlying sequences and younger overlying deposits. The latter often are subaerial or subaquatic deposits associated with late-Glacial to Holocene thermokarst dynamics that led to Yedoma degradation during the deglacial and Holocene warming of these regions (38,39,40). Figure 1: Joint Russian-German fieldwork sites in NE Siberia labeled with the year of expedition. Besides geomorphological and cryolithological studies, extensive paleo-ecological investigations were carried out on zoological (41,42,43,44,45) and botanic fossils (46,47,48,49,50,51) to derive quantitative and qualitative reconstructions late Pleistocene Beringian environments and climate conditions. New methods in geochronology were also tested (52,53,54,55). In addition to the sedimentary components of the frozen deposits, segregated ground ice and in particular the large syngenetic ice wedges of Yedoma Ice Complex were also studied as geochemical and stable isotope archives of paleoclimate (56,57,58, 59,60,61,62). In addition, a range of remote sensing methods in combination with GIS analyses (63,64,65) and geophysical surveys (66) were used for large-scale analyses of landscape changes associated with Yedoma Ice Complex degradation (67,68,69). In the last few years, an additional important focus has been on using modern biogeochemical methods of organic matter analysis to characterize the frozen organic matter in Yedoma Ice Complex deposits and for permafrost carbon pool calculations (70, 71,72,73,74,75,76,77) as well as microbiological studies (78) and genetic studies on fossil DNA (79,80). The rich body of scientific data and literature produced in Russian-German co-authorship within the more than 25 years of joint research on Yedoma Ice Complex represents an important cornerstone for understanding the Late Quaternary evolution of Siberian Yedoma regions, its role in the Earth System, and its feedbacks with climate and ecosystems. References 1. Schirrmeister, L., Dietze, E., Matthes, H., Grosse, G., Strauss, J., Laboor, S., Ulrich, M., Kienast, F., and Wetterich, S. (2020) The genesis of Yedoma Ice Complex permafrost – grain-size endmember modeling analysis from Siberia and Alaska, E&G Quaternary Sci. J., 69, 33–53, doi: 10.5194/egqsj-69-33-2020. 2. Schirrmeister, L., Froese, D., Tumskoy, V., Grosse,G., Wetterich, S. (2013.) Yedoma: Late Pleistocene ice-rich syngenetic permafrost of Beringia. In: Elias S.A. (ed.) The Encyclopedia of Quaternary Science 2nd edition, vol. 3, pp. 542-552. Amsterdam: Elsevier. 3. Schirrmeister, L., Kunitsky, V.V., Grosse, G., Wetterich, S., Meyer, H., Schwamborn, G., Babiy, O., Derevyagin, A.Y., and Siegert, C.: Sedimentary characteristics and origin of the Late Pleistocene Ice Complex on North-East Siberian Arctic coastal lowlands and islands - a review. Quaternary International 241, 3-25, doi: 10.1016/j.quaint.2010.04.004, 2011. 4. Kunitsky, V., Schirrmeister, L., Grosse, G., Kienast, F. (2002). Snow patches in nival landscapes and their role for the Ice Complex formation in the Laptev Sea coastal lowlands, Polarforschung, 70, 53-67, doi:10.2312/polarforschung.70.53. 5. Andreev, A. , Siegert, C. , Klimanov, V. A. , Derevyagin, A. Y. , Shilova, G. N. and Melles, M. (2002) Late Pleistocene and Holocene vegetation and climate changes in the Taymyr lowland, Northern Siberia Quaternary research, 57, pp. 138-150 . 6. Andreev, A. , Tarasov, P. E. , Siegert, C. , Ebel, T. , Klimanov, V. A. , Melles, M. , Bobrov, A. A. , Derevyagin, A. Y. , Lubinski, D. J. and Hubberten, H. W. (2003) Vegetation and climate changes on the northern Taymyr, Russia during the Upper Pleistocene and Holocene reconstructed from pollen records , Boreas, 32 (3), pp. 484-505 . 7. Chizhov, A. B. , Derevyagin, A. Y. , Simonov, E. F. , Hubberten, H. W. and Siegert, C. (1997) Isotopic composition of ground ice at the Labaz Lake region (Taymyr). Kriosfera Zemlii (Earth Cryoshere), 1, No 3, pp. 79-84 . (in Russian), 8. Derevyagin, A.Yu., Chizhov, A.B., Brezgunov, V.S., Siegert, C., Hubberten, H.-W., 1999.Isotopic composition of ice wedges of Cape Sabler (Lake Taymyr). Kriosfera Zemlii (Earth Cryosphere) 3/3, 41-49 (in Russian). 9. Kienast, F., Siegert, C., Dereviagin, A., Mai, H.D. Climatic implications of Late Quaternary plant macrofossil assemblages from the Taymyr Peninsula, Siberia, Global and Planetary Change, Volume 31, Issues 1–4, 265-281, 2001, https://doi.org/10.1016/S0921-8181(01)00124-2. 10. Kienel, U. , Siegert, C. and Hahne, J. (1999) Late Quarternary paeloenvironmental reconstruction from a permafrost sequence (Northsiberian Lowland, SE Taymyr Peninsula) - a multidisciplinary case study, Boreas, 28 (1), pp. 181-193 . 11. Siegert C., Derevyagin A.Y., Shilova G.N., Hermichen WD., Hiller A. (1999) Paleoclimatic Indicators from Permafrost Sequences in the Eastern Taymyr Lowland. In: Kassens H. et al. (eds) Land-Ocean Systems in the Siberian Arctic. Springer, Berlin, Heidelberg. 12. Bobrov, A.A., Müller, S., Chizhikova, N.A., Schirrmeister, L., Andreev, A.A.(2009).Testate Amoebae in Late Quaternary Sediments of the Cape Mamontov Klyk (Yakutia), Biology Bulletin, 36(4), 363-372. 13. Schirrmeister, L., Grosse, G., Kunitsky, V., Magens, D., Meyer, H., Dereviagin, A., Kuznetsova, T., Andreev, A., Babiy, O., Kienast, F., Grigoriev, M., Overduin, P.P., and Preusser, F.: Periglacial landscape evolution and environmental changes of Arctic lowland areas for the last 60,000 years (Western Laptev Sea coast, Cape Mamontov Klyk), Polar Research, 27(2), 249-272, doi: 10.1111/j.1751-8369.2008.00067.x, 2008. 14. Winterfeld, M., Schirrmeister, L., Grigoriev, M., Kunitsky, V.V., Andreev, A., and Overduin, P.P.: Permafrost and Landscape Dynamics during the Late Pleistocene, Western Laptev Sea Shelf, Siberia, Boreas 40(4), 697–713, doi: 10.1111/j.1502-3885.2011.00203.x, 2011. 15. Siegert, C., Schirrmeister, L., and Babiy, O.: The sedimentological, mineralogical and geochemical composition of late Pleistocene deposits from the ice complex on the Bykovsky peninsula, northern Siberia, Polarforschung, 70, 2000, 3-11, doi: 10.2312/polarforschung.70.3, 2002. 16. Schirrmeister, L., Siegert, C., Kuznetsova, T., Kuzmina, S., Andreev, A.A., Kienast, F., Meyer, H., and Bobrov, A.A.: Paleoenvironmental and paleoclimatic records from permafrost deposits in the Arctic region of Northern Siberia, Quaternary International, 89, 97-118, doi: 10.1016/S1040-6182(01)00083-0, 2002. 17. Schirrmeister, L., Siegert, C., Kunitzky, V.V., Grootes, P.M., and Erlenkeuser, H.: Late Quaternary ice-rich permafrost sequences as a paleoenvironmental archive for the Laptev Sea Region in northern Siberia, International Journal of Earth Sciences, 91, 154-167, doi: 10.1007/s005310100205, 2002. 18. Schirrmeister, L., Schwamborn, G., Overduin, P.P., Strauss, J., Fuchs, M.C., Grigoriev, M., Yakshina, I., Rethemeyer, J., Dietze, E., and Wetterich, S.: Yedoma Ice Complex of the Buor Khaya Peninsula (southern Laptev Sea), Biogeosciences 14, 1261-1283, doi: 10.5194/bg-14-1261-2017, 2017. 19. Schirrmeister, L., Kunitsky, V.V., Grosse, G., Schwamborn, G., Andreev, A.A., Meyer, H., Kuznetsova, T., Bobrov, A., and Oezen, D.: Late Quaternary history of the accumulation plain north of the Chekanovsky Ridge (Lena Delta, Russia) - a multidisciplinary approach, Polar Geography, 27(4), 277-319, doi: 10.1080/789610225, 2003. 20. Schirrmeister, L., Grosse, G. Schnelle, M., Fuchs, M., Krbetschek, M., Ulrich, M., Kunitsky, V., Grigoriev, M., Andreev, A. Kienast, F., Meyer, H., Klimova, I., Babiy, O., Bobrov, A., Wetterich, S., and Schwamborn, G.: Late Quaternary paleoenvironmental records from the western Lena Delta, Arctic Siberia, Palaeogeography, Palaeoclimatology, Palaeoecology 299, 175–196, doi: 10.1016/j.quascirev.2009.11.017, 2011. 21. Schwamborn, G., Rachold, V., and Grigoriev, M.N.: Late Quaternary sedimentation history of the Lena Delta, Quaternary International 89, 119–134, doi: 10.1016/S1040-6182(01)00084-2, 2002. 22. Wetterich, S., Kuzmina, S., Andreev, A.A., Kienast, F., Meyer, H., Schirrmeister, L., Kuznetsova, T., and Sierralta, M.: Palaeoenvironmental dynamics inferred from late Quaternary permafrost deposits on Kurungnakh Island, Lena Delta, Northeast Siberia, Russia, Quaternary Science Reviews, 27, 1523-1540, doi: 10.1016/j.quascirev.2008.04.007, 2008. 23. Andreev, A.A., Grosse, G., Schirrmeister, L., Kuzmina, S.A., Novenko, E.Yu., Bobrov, A.A., Tarasov, P. E., Kuznetsova, T.V., Krbetschek, M., Meyer, H., and Kunitsky, V.V.: Late Saalian and Eemian palaeoenvironmental history of the Bol'shoy Lyakhovsky Island (Laptev Sea region, Arctic Siberia), Boreas 33(4), 319-348, doi:10.1080/03009480410001974, 2004. 24. Andreev, A., Grosse, G., Schirrmeister, L., Kuznetsova, T.V., Kuzmina, S.A., Bobrov, A.A., Tarasov, P.E., Novenko, E.Yu., Meyer, H., Derevyagin, A.Yu., Kienast, F., Bryantseva, A., and Kunitsky, V.V.: Weichselian and Holocene palaeoenvironmental history of the Bol’shoy Lyakhovsky Island, New Siberian Archipelago, Arctic Siberia, Boreas 38(1), 72–110, doi: 10.1111/j.1502-3885.2008.00039.x, 2009. 25. Wetterich, S., Rudaya, N., Meyer, H., Opel, T., and Schirrmeister, L.: Last Glacial Maximum records in permafrost of the East Siberian Arctic, Quaternary Science Reviews 30, 3139-3151, doi: 10.1016/j.quascirev.2011.07.020, 2011. 26. Wetterich, S., Rudaya, N., Andreev, A.A., Opel, T., Schirrmeister, L., Meyer, H., and Tumskoy, V.: Ice Complex formation in arctic East Siberia during the MIS3 Interstadial, Quaternary Science Reviews 84: 39-55, doi:. 10.1016/j.quascirev.2013.11.009, 2014. 27. Wetterich, S.; Tumskoy:V.E., Rudaya, N., Kuznetsov, V., Maksimov, F., Opel T. , Meyer H., Andreev, A.A., Schirrmeister, L (2016) Ice Complex permafrost of MIS5 age in the Dmitry Laptev Strait coastal region (East Siberian Arctic). Quaternary Science Reviews, 147:298-31, doi.org/10.1016/j.quascirev.2015.11.016. 28. Wetterich, S., Rudaya, N., Kuznetsov V., Maksimov, F., T. Opel, Meyer, H., Guenther, F., Bobrov, A., Raschke, E., Zimmermann, H., Strauss, J., Fuchs, M.C., Schirrmeister, L. (2019) Recurrent Ice Complex formation in arctic eastern Siberia since about 200 ka. Quaternary Research 92 (2); 530-548, doi.org/10.1017/qua.2019.6. 29. Wetterich, S., Schirrmeister, L., Andreev A. A., Pudenz, M., Plessen, B, Meyer, H., Kunitsky, V. V. (2009). Eemian and Late Glacial/Holocene palaeoenvironmental records from permafrost sequences at the Dmitry Laptev Strait (NE Siberia, Russia), Palaeogeography, Palaeoclimatology, Palaeoecology 279: 73-95 doi:10.1016/j.palaeo.2009.05.002. 30. Strauss, J., Schirrmeister, L., Wetterich, S., Borchers, A, and Davydov S.P.: Grain-size properties and organic-carbon stock of Yedoma Ice Complex permafrost from the Kolyma lowland, northeastern Siberia. GBC. 26: GB3003, doi: 10.1029/2011GB004104, 2012. 31. Ashastina, K., Schirrmeister, L., Fuchs M., and Kienast F.: Palaeoclimate characteristics in interior Siberia of MIS 6–2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands, Clim. Past, 13, 795–818, doi: 10.5194/cp-13-795-2017, 2017. 32. Kunitsky, V.V., Syromyatnikov, I.I., Schirrmeister, L., Skachkov, Yu.B., Grosse, G., Wetterich, S., and Grigoriev, M.N.: Ice-rich permafrost and thermal denudation in the Kirgillyakh area, Kriosfera Zemli. 17(1), 56-68, 2013 (in Russian). 33. Popp, S., Diekmann,B., Meyer, H., Siegert, C.,Syromyatnikov, I., Hubberten, H.-W. Palaeoclimate Signals as Inferred from Stable-isotope Composition of Ground Ice in the Verkhoyansk Foreland, Central Yakutia. Permafrost and Periglac. Process. 17: 119–132 (2006) DOI: 10.1002/ppp.556 34. Popp, S., Belolyubsky, I., Lehmkuhl, F., Prokopiev, A., Siegert, C., Spektor, V., Stauch, G., Diekmann,B. Sediment provenance of late Quaternary morainic, fluvialand loess-like deposits in the southwestern VerkhoyanskMountains (eastern Siberia) and implications for regionalpalaeoenvironmental reconstructions. Geol. J.42: 477–497 (2007), DOI: 10.1002/gj.1088 35. Siegert, C. , Sergeyenko, A. I. and Schirrmeister, L. (2017) Late Quaternary Deposits of the Northern Verkhoyansk Mountains: Geochronology and Questions of their Genesis (in Russian), Bulletin of the Commission for Study of the Quaternary = БЮЛЛЕТЕНЬ КОМИССИИ ПО ИЗУЧЕНИЮ ЧЕТВЕРТИЧНОГО ПЕРИОДА, 75 , pp. 100-112 . 36. Siegert, C. , Stauch, G. , Lehmkuhl, F. , Sergeyenko, A. I. , Diekmann, B. , Popp, S. and Belolyubsky, I. N. (2007) Development of glaciation in the Verkhoyansk Range and its foreland during the Pleistocene: Results of new investigations., Regionalnaya Geologiya i Metallogeniya (Regional Geology and Metallogeny), No. 30-31(in Russian)., 222 . 37. Ulrich, M., Morgenstern, A., Günther, F., Reiss, D. Bauch, K. E., Hauber, E., Rössler, S. and Schirrmeister, L. (2010) Thermokarst in Siberian ice-rich permafrost: Comparison to asymmetric scalloped depressions on Mars, Journal of Geophysical Research, 115, E10009 . doi:10.1029/2010JE003640 , 38. Morgenstern, A. , Grosse, G. , Günther, F. , Fedorova, I. and Schirrmeister, L. (2011): Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta. The Cryosphere, 5(4), 849–867, doi:10.5194/tc-5-849-2011. 39. Morgenstern, A. , Ulrich, M. , Günther, F. , Roessler, S. , Fedorova, I. V. , Rudaya, N. A. , Wetterich, S. , Boike, J. and Schirrmeister, L. (2013). Evolution of thermokarst in East Siberian ice-rich permafrost: A case study, Geomorphology, 201 , 363-379. doi:10.1016/j.geomorph.2013.07.011 40. Biskaborn, B. , Herzschuh, U. , Bolshiyanov, D. Y. , Schwamborn, G. and Diekmann, B. (2013) Thermokarst Processes and Depositional Events in a Tundra Lake, Northeastern Siberia, Permafrost and Periglac. Process.24: 160–174 doi:https://doi.org/10.1002/ppp.1769, 41. Kuznetsova, T. V. , Sulerzhitsky, L. D. , Andreev, A. , Siegert, C. , Schirrmeister, L. and Hubberten, H. W. (2003) Influence of Late Quaternary paleoenvironmental conditions on the distribution of mammals fauna in the Laptev Sea region , Occasional Papers in Earth Sciences, 5 , pp. 58-60 . 42. Kuznetsova T.V., Tumskoy V.E., Schirrmeister L., Wetterich S., (2019.) Paleozoological characteristics of the Late Neo-Pleistocene - Holocene sediments of Bykovsky Peninsula, Northern Yakutia (Палеозоологическая характеристика поздненеоплейстоценовых – голоценовых отложений Быковского Полуострова (Северная Якутия). Zoological Journal 98(11), 1268-1290. Special issue in honor of Andrey Sher. (in Russian) doi: 10.1134/S0044513419110102. 43. Bobrov, A. A. , Andreev, A. , Schirrmeister, L. and Siegert, C. (2004) Testate amoebae (Protozoa: Testacea) as bioindicators in the Late Quaternary deposits of the Bykovsky Peninsula, Laptev Sea, Russia , Palaeogeography palaeoclimatology palaeoecology, 209 , pp. 165-181 . doi:https://doi.org/10.1016/J.PALAEO.2004.02.012 44. Wetterich, S., Schirrmeister, L., Pietrzeniuk, E. (2005). Freshwater ostracodes in Quaternary permafrost deposits from the Siberian Arctic, Journal of Paleolimnology, 34, 363-376. doi:10.1007/s10933-005-5801-y 45. Müller, S., Bobrov, A. A., Schirrmeister, L., Andreev, A. A., Tarasov, P. E. (2009). Testate amoebae record from the Laptev Sea coast and its implication for the reconstruction of Late Pleistocene and Holocene environments in the Arctic Siberia, Palaeogeography, Palaeoclimatology, Palaeoecology 271(3-4), 301-315. doi:10.1016/j.palaeo.2008.11.003 46. Andreev, A.A., Schirrmeister, L., Siegert, C., Bobrov, A.A., Demske, D., Seiffert, M., Hubberten, H.-W. (2002). Paleoenvironmental changes in Northeastern Siberia during the Late Quaternary - evidence from pollen records of the Bykovsky Peninsula, Polarforschung, 70, 13-25, doi:10.2312/polarforschung.70.13. 47. Andreev, A.A.; Schirrmeister, L.; Tarasov , P.E.; Ganopolski , A.; Brovkin V.; Siegert, C.; Hubberten, H.-W. (2011). Vegetation and climate history in the Laptev Sea region (arctic Siberia) during Late Quaternary inferred from pollen records. Journal of Quaternary science reviews. 30, 2182-2199 doi:10.1016/j.quascirev.2010.12.026. 48. Kienast, F. , Schirrmeister, L. , Siegert, C. and Tarasov, P. (2005) Palaeobotanical evidence for warm summers in the East Siberian Arctic during the last cold stage, Quaternary Research, 63 (3), pp. 283-300. doi:https://doi.org/10.1016/j.yqres.2005.01.003 , 49. Kienast, F., Tarasov, P., Schirrmeister, L., Grosse, G., Andreev, A.A. (2008). Continental climate in the East Siberian Arctic during the last interglacial: implications from palaeobotanical records, Global and Planetary Change, 60(3/4), 535-562. doi:10.1016/j.gloplacha.2007.07.004 50. Kienast, F., Wetterich, S., Kuzmina, S., Schirrmeister, L., Andrev, A., Tarasov, P., Nazarova, L., Kossler, A., Frolova, A., Kunitsky, V. V.(2011) Paleontological records indicate the occurrence of open woodlands in a dry inland climate at the present-day Arctic coast in western Beringia during the last interglacial. Quaternary Science Reviews 30: 2134-2159, doi:10.1016/j.quascirev.2010.11.024. 51. Palagushkina, O.V., Wetterich, S., Schirrmeister, L., Nazarova, L.B. (2017) Modern and fossil diatom assemblages from Bol'shoy Lyakhovsky Island (New Siberian Archipelago, Arctic Siberia). Contemporary Problems of Ecology, 10, (4), 380–394. doi: 10.1134/S1995425517040060. 52. Gilichinsky, D. A. , Nolte, E., Basilyan, A.E., Beer, J., Blinov, A., Lazarev, V., Kholodov, A., Meyer, H., Nikolsky, P.A., Schirrmeister, L., Tumskoy, V. (2007). Dating of syngenetic ice wedges in permafrost with 36Cl and 10Be, Quaternary science reviews. 26, 1547-1556. doi:10.1016/j.quascirev.2007.04.004 53. Blinov A.V., Beer J., Tikhomirov D.A., Schirrmeister L., Meyer H., Abramov A.A., Basylyan A.E., Nikolskiy P.A., Tumskoy V.E., Kholodov A.L., Gilichinsky D.A. (2009) Permafrost dating with the cosmogenic radionuclides ( Report 1) (= Датирование многолетнемерзлых пород с помощью космогенных радионуклидов (сообщение 1). Kriosfera Zemli 13,( 2), 3-15 (in Russian). 54. Blinov, A., Alfimov, V., Beer, J., Gilichinsky, D., Schirrmeister, L., Kholodov, A., Nikolskiy, P., Opel, T., Tikhomirov, D., Wetterich, S.(2009).36Cl/Cl ratio in ground ice of East Siberia and its application for chronometry, Geochemistry, Geophysics, Geosystems (G3). 10(1), doi: 10.1029/2009GC002548. 55. Schirrmeister, L., Oezen, D., Geyh, M.A. (2002). 230Th/U dating of frozen peat, Bol'shoy Lyakhovsky Island (North Siberia), Quaternary research, 57, 253-258. doi:10.1006/qres.2001.2306. 56. Meyer, H. , Derevyagin, A. Y. , Siegert, C. and Hubberten, H. W. (2002) Paleoclimate studies on Bykovsky Peninsula, North Siberia - hydrogen and oxygen isotopes in ground ice , Polarforschung 70:, pp. 37-51 . 57. Derevyagin, A. Y., Chizhov, A. , Meyer, H. , Opel, T. , Schirrmeister, L. and Wetterich, S. (2013). Isotopic composition of texture ices, Laptev Sea coast , Kriosfera Zemlii (Earth Cryosphere), XVII (3), pp. 27-34 (in Russian). 58. Meyer, H. , Derevyagin, A. Y. , Siegert, C. , Schirrmeister, L. and Hubberten, H. W. (2002) Paleoclimate reconstruction on Big Lyakhovsky Island, North Siberia - Hydrogen and oxygen isotopes in ice wedges , Permafrost and periglacial processes, 13 , pp. 91-105 . 59. Opel, T., Dereviagin, A., Meyer, H., Schirrmeister, L., Wetterich, S. (2010).Paleoclimatic information from stable water isotopes of Holocene ice wedges at the Dmitrii Laptev Strait (Northeast Siberia), Permafrost and Periglacial Processes. 22 (1), 84-100, doi:10.1002/ppp.667. 60. Opel, T., Wetterich, S., Meyer, H., Dereviagin, A.Yu., Fuchs, M.C., and Schirrmeister, L.: Ground-ice stable isotopes and cryostratigraphy reflect late Quaternary palaeoclimate in the Northeast Siberian Arctic (Oyogos Yar coast, Dmitry Laptev Strait). Clim. Past, 13, 587–611, 2017, doi: 10.5194/cp-13-587-2017, 2017. 61. Opel, T., Murton, J. B., Wetterich, S., Meyer, H., Ashastina, K., Günther, F., Grotheer, H., Mollenhauer, G., Danilov, P. P., Boeskorov, V., Savvinov, G. N., Schirrmeister, L. (2019) Past climate and continentality inferred from ice wedges at Batagay megaslump in the Northern Hemisphere's most continental region, Yana Highlands, interior Yakutia, Clim. Past, 15, 1443–1461, doi: 10.5194/cp-15-1443-2019. 62. Ulrich, M., Grosse, G., Strauss, J. and Schirrmeister, L. (2014): Quantifying wedge-ice volumes in yedoma and thermokarst basin deposits, Permafrost and Periglacial Processes 25, 151–161. doi:10.1002/ppp.1810. 63. Grosse, G., Schirrmeister, L., Siegert, C., Kunitsky, V.V., Slagoda, E.A., Andreev, A.A., and Dereviagyn, A.Y.: Geological and geomorphological evolution of a sedimentary periglacial landscape in Northeast Siberia during the Late Quaternary, Geomorphology, 86(1/2), 25-51, doi:10.1016/j.geomorph.2006.08.005, 2007. 64. Grosse, G., Schirrmeister, L., Kunitsky, V. V., Hubberten, H. -W. (2005). The Use of CORONA Images in Remote Sensing of Periglacial Geomorphology: An Illustration from the NE Siberian Coast, Permafrost and periglacial processes, 16, 163-172. doi:10.1002/ppp.509 65. Grosse, G., Robinson, J.E., Bryant, R., Taylor, M.D., Harper, W., DeMasi, A., Kyker-Snowman, E., Veremeeva, A., Schirrmeister, L., Harden, J. (2013). Distribution of late Pleistocene ice-rich syngenetic permafrost of the Yedoma Suite in east and central Siberia, Russia. U.S. Geological Survey Open File Report 2013-1078, 37p. 66. Schennen, S., Tronicke, J., Wetterich, S., Allroggen, N., Schwamborn, G., Schirrmeister, L. (2016) 3D GPR imaging of Ice Complex deposits in northern East Siberia, Geophysics 81(1), WA185-WA192, doi: 10.1190/GEO2015-0129.1. 67. Günther, F. , Overduin, P. P. , Yakshina, I. A. , Opel, T. , Baranskaya, A. V. and Grigoriev, M. N. (2015) Observing Muostakh disappear: permafrost thaw subsidence and erosion of a ground-ice-rich island in response to arctic summer warming and sea ice reduction , The Cryosphere, 9 (1), pp. 151-178 . doi.org/10.5194/tc-9-151-2015 68. Günther, F. , Overduin, P. P. , Sandakov, A. V. , Grosse, G. and Grigoriev, M. N. (2013) Short- and long-term thermo-erosion of ice-rich permafrost coasts in the Laptev Sea region, Biogeosciences, 10 , pp. 4297-4318 . doi:https://doi.org/10.5194/bg-10-4297-2013 69. Overduin, P. P. , Strzelecki, M. C. , Grigoriev, M. N. , Couture, N. , Lantuit, H. , St-Hilaire-Gravel, D. , Günther, F. and Wetterich, S. (2013) Coastal changes in the Arctic, Geological Society of London Special Publication, 388 . doi:https://doi.org/10.1144/SP388.13 70. Strauss J., Schirrmeister L., Grosse G., Wetterich S., Ulrich M., Herzschuh U., H.-W.Hubberten (2013). The Deep Permafrost Carbon Pool of the Yedoma Region in Siberia and Alaska. GRL 40, 6165-6170. doi 10.1002/2013GL058088. 71. Strauss, J., Schirrmeister, L., Mangelsdorf, K., Eichhorn, L., Wetterich S., and Herzschuh U.: Organic matter quality of deep permafrost carbon - a study from Arctic Siberia. Biogeosciences, 12, 2227–2245, doi: 10.5194/bg-12-2227-2015, 2015. 72. Strauss,J., Schirrmeister, L., Grosse, G., Fortier, D., Hugelius, G., Knoblauch, C., Romanovsky, V., Schädel, C., Schneider von Deimling, T., Schuur, E.A.G., Shmelev, D., Ulrich, M.,, Veremeeva, A. (2017). Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability. Earth-Science Reviews 172, 75-86, doi: 10.1016/j.earscirev.2017.07.007. 73. Stapel, J. G., L. Schirrmeister, P. P. Overduin, S. Wetterich, J. Strauss, B. Horsfield, and K. Mangelsdorf (2016), Microbial lipid signatures and substrate potential of organic matter in permafrost deposits - implications for future greenhouse gas production, J. Geophys. Res. Biogeosci., 121, doi: 10.1002/2016JG003483. 74. Stapel, J.G, Schwamborn, G., Schirrmeister, L., Horsfield, B. and Mangelsdorf, K. (2018) Substrate potential of last interglacial to Holocene permafrost organic matter for future microbial greenhouse gas production. Biogeosciences, 15, 1969–1985, doi: 10.5194/bg-15-5423-2018. 75. Walz, J., Knoblauch, C., Tigges, R., Opel, T., Schirrmeister, L., and Pfeiffer, E.-M. (2018) Greenhouse gas production in degrading ice-rich permafrost deposits in northeast Siberia. Biogeosciences, 15, 5423–5436, doi: 10.5194/bg-2018-225. 76. Fuchs, M. , Grosse, G. , Strauss, J. , Günther, F. , Grigoriev, M. N. , Maximov, G. M. and Hugelius, G. (2018) Carbon and nitrogen pools in thermokarst-affected permafrost landscapes in Arctic Siberia , Biogeosciences, 15 , pp. 953-971 . 77. Kusch, S., Winterfeld, M., Mollenhauer, G., Höfle, S.T., Schirrmeister, L., Schwamborn, G., and Rethemeyer, J. (2019) Glycerol dialkyl glycerol tetraethers (GDGTs) in high latitude Siberian permafrost: Diversity, environmental controls, and implications for proxy applications. Organic Geochemistry 136, 103888, doi: 10.1016/j.orggeochem.2019.06.009. 78. Mitzscherling, J., Horn, F., Winterfeld, M., Mahler, L., Kallmeyer, J., Overduin, P.P., Schirrmeister, L., Winkel, M., Grigoriev, M.N., Wagner, D., Liebner, S. (2019) (6bial community composition and abundance after millennia of submarine permafrost warming. Biogeosciences, 16, 3941–3958, doi: 10.5194/bg-16-3941-2019. 79. Zimmermann, H.H., Raschke, E., Epp, L.S., Stoof-Leichsenring, K.R., Schirrmeister, L., Schwamborn, G., Herzschuh, U. (2017). The history of tree and shrub taxa on Bol’shoy Lyakhovsky Island (New Siberian Archipelago) since the last interglacial uncovered by sedimentary ancient DNA and pollen data. Genes 8(10), E273; doi: 10.3390/genes8100273. 80. Zimmermann, H.H., Raschke, E., Epp, L.S., Stoof-Leichsenring, K., Schwamborn, G., Schirrmeister, L., Overduin, P.P., Herzschuh, U. (2017) Sedimentary ancient DNA and pollen reveal the composition of plant organic matter in Late Quaternary permafrost sediments of the Buor Khaya Peninsula (north-eastern Siberia). Biogeosciences 14, 575-596, doi:10.5194/bg-14-575-2017

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.

Situated in the Yana-Highlands, the Batagai profile is one of the few inland permafrost outcrops in Yakutia and, for the time being, the biggest and most active thermoerosional cirque worldwide. With Yerkhoyansk recorded as place of the pole of cold, the Yana Highlands represent the region with the most severe climatic continentality in the northern hemisphere. In contrast to the numerous sequences in today’s coastal lowlands, the Batagai sequence was always unaffected by maritime climate influence during its formation and thus better indicates the macro-climate evolution in NE-Siberia. As result of intense thermal degradation, the outcrop formed within 30 years only and cut deep into ice-rich permafrost deposits. The 60 m deep outcrop is now about 850 m in diameter, but erosion rates as high as 15 m/year are changing the dimensions continuously. The Batagai profile thus represents a unique window into the past (and future) of ice-rich permafrost deposits in Yakutia. Field based observations have shown that the permafrost sequence consists of 4 distinct units: below a thin Holocene surface cover, a 30 meter thick Ice Complex with characteristic thick ice wedges has formed. At the base of the Ice Complex, there is an up to 2 m thick layer of plant material including large woody remains. Subjacent to this organic layer of supposedly Eemian origin, there is a horizontally stratified unit composed of silty-sand and without thick syngenetic ice wedges presumably deposited during the Middle Pleistocene. At the very base of the sequence, there appears to emerge another unit including syngenetic ice wedges. This unit was not accessible for sampling. The accessible upper about 45 meter of the sequence were sampled from top to bottom in one meter steps using, due to the difficult accessibility of the permafrost wall, thermokarst mounds in the less steep part of the outcrop. The samples were taken for sedimentological analyses and especially for plant macrofossil and other palaeoecological studies. Whereas sediments give insight into the genesis of the sequence, fossil plant macroremains provide information on local vegetation patterns and habitats at the time of deposition; while palynological analyses reflect the regional vegetation and climate history. First palaeobotanical results will be represented in Session 13: Palaeoenvironments in permafrost affected areas. The sedimentological analyses revealed that, despite clearly delimitable bedding units visible at the outcrop, there is no distinct litho-stratigraphical differentiation recognizable in the grain size distribution or other sedimentological parameters. Accordingly, the sequence is characterized by a grain size signature typical for Ice Complex deposits. In comparison to other Yakutian ice-rich permafrost sequences, e.g. in the coastal lowlands, the Batagai profile is however distinguished by a higher fraction of fine sand over the whole recorded sequence. This might be due to increased aeolian deposition from local sources, e.g. from barren ridges in the highlands uncovered by vegetation. The assumption that aeolian deposition played a substantial role in the formation of the sequence is also suggested by impressive dunes in the immediate vicinity of the profile at the boundary of Batagai city.

Perennially-frozen deposits are considered as excellent paleoenvironmental archives similar to lacustrine, deep marine, and glacier records because of the long-term and good preservation of fossil records under stable permafrost conditions. A permafrost tunnel in the Vault Creek Valley (Chatanika River Valley, near Fairbanks) exposes a sequence of frozen deposits and ground ice that provides a comprehensive set of proxies to reconstruct the late Quaternary environmental history of Interior Alaska. The multi-proxy approach includes different dating techniques (radiocarbon-accelerator mass spectrometry [AMS 14C], optically stimulated luminescence [OSL], thorium/uranium radioisotope disequilibria [230Th/U]), as well as methods of sedimentology, paleoecology, hydrochemistry, and stable isotope geochemistry of ground ice. The studied sequence consists of 36-m-thick late Quaternary deposits above schistose bedrock. Main portions of the sequence accumulated during the early and middle Wisconsin periods. The lowermost unit A consists of about 9-m-thick ice-bonded fluvial gravels with sand and peat lenses. A late Sangamon (MIS 5a) age of unit A is assumed. Spruce forest with birch, larch, and some shrubby alder dominated the vegetation. High presence of Sphagnum spores and Cyperaceae pollen points to mires in the Vault Creek Valley. The overlying unit B consists of 10-m-thick alternating fluvial gravels, loess-like silt, and sand layers, penetrated by small ice wedges. OSL dates support a stadial early Wisconsin (MIS 4) age of unit B. Pollen and plant macrofossil data point to spruce forests with some birch interspersed with wetlands around the site. The following unit C is composed of 15-m-thick ice-rich loess-like and organic-rich silt with fossil bones and large ice wedges. Unit C formed during the interstadial mid-Wisconsin (MIS 3) and stadial late Wisconsin (MIS 2) as indicated by radiocarbon ages. Post-depositional slope processes significantly deformed both, ground ice and sediments of unit C. Pollen data show that spruce forests and wetlands dominated the area. The macrofossil remains of Picea, Larix, and Alnus incana ssp. tenuifolia also prove the existence of boreal coniferous forests during the mid-Wisconsin interstadial, which were replaced by treeless tundra-steppe vegetation during the late Wisconsin stadial. Unit C is discordantly overlain by the 2-m-thick late Holocene deposits of unit D. The pollen record of unit D indicates boreal forest vegetation similar to the modern one. The permafrost record from the Vault Creek tunnel reflects more than 90 ka of periglacial landscape dynamics triggered by fluvial and eolian accumulation, and formation of ice-wedge polygons and post-depositional deformation by slope processes. The record represents a typical Wisconsin valley-bottom facies in Central Alaska.

Ice-rich permafrost that formed in glacial periods of the Quaternary is highly vulnerable to thaw under ongoing climate change and anthropogenic disturbance. Permafrost degradation processes such as thermokarst, thermo-denudation and thermo-erosion are actively shaping modern periglacial landscapes. Retrogressive thaw slumps – also referred to as thermo-cirques – represent a highly dynamic geomorphologic feature in ice-rich permafrost regions. These rapidly forming landforms consist of a steep headwall surrounding a gently inclined slump floor where sediment erosion and accumulation takes place simulatenously and develop as a result of rapid permafrost thaw over several decades. Thaw slumps are commonly found in permafrost areas with near-surface, thick ground-ice layers that are susceptible to thermo-denudation and subsequent mass displacement through cryogenic landslides (Leibman et al., 2008). Thaw slumps are particularly frequent along riverbanks and coastlines in the Northwest American and West Siberian Arctic, where they are typically initiated by lateral erosion of the bluff toe. In these regions, buried glacier ice (massive ground ice) bodies or ice-rich glacial till have been mapped. Given their exceptional size of up to 40 ha in area and 25 m high headwalls, so-called mega slumps in northwestern Canada represent primary terrain destabilization features with different environmental settings than surrounding areas (Lantuit et al., 2012), but are a significant source for sediment and solute delivery to adjacent lakes and streams (Kokelj et al., 2013). However, in East Siberia, retrogressive thaw slumps have been described in the syngenetic Late Pleistocene Ice Complex (Yedoma) permafrost deposits, where massive ice wedges and segregated intrasedimentary ice results in total volumetric ice contents of up to 80-90%. Such retrogressive thaw slumps in syngenetic permafrost were investigated for example on the coastal area of the Dmitry Laptev Strait (Are et al., 2005). However, Yedoma deposits are also found on slopes of the Verkhoyan Mountain Range (Slagoda, 1991) and in valleys of surrounding foothills (Grosse et al., 2007) beyond the Yedoma main distributional range in the coastal lowlands of the Laptev and East Siberian seas. The Batagay mega slump is at least two times larger than any previously described thaw slump, has been discovered near the village of Batagay, and has been the subject of some recent cryostratigraphical analysis (Kunitsky et al 2013). It exposes a profile of Yedoma deposits, reaching a thickness of 7 to 22 m in that area (Slagoda, 1991) and underlying ice-rich periglacial alluvial sand deposits of around 60 m thickness (Kunitsky et al., 2013). The observed rapid development of thermo-denudation at rates of up to 15 m per year, poses the question of whether the larger portions of the entire region between the Verkhoyan and Cherskiy mountain ranges may be more vulnerable to deep and rapid thaw following disturbances such as forest fires or forest clearance. Using a set of historical remote sensing data, Kunitsky et al. (2013) suggest that depression-like structures on the Kirgillyakh-Khatyngnakhskoy Mountain saddle begin in the early 1970s. The initial disturbance causing rapid thermo-denudational development of the Batagay mega thaw slump started at the end of the 1980s. Here we present data from a remote sensing investigation of the mega slump (. in order to assess the planimetric dimensions and its recent expansion rates. We acquired very high resolution satellite imagery from QuickBird, IKONOS, KOMPSAT-2, WorldView-1 and WorldView-2, spanning a timeframe from 2006 to 2014. Aerotriangulation of the entire dataset was performed to ensure consistent co-registration between images. In addition, for terrain correction through ortho-rectification and for volumetric analyses of the entire mega slump, we derived an accurate digital elevation model (DEM) with 2m ground resolution from along and across track WorldView stereo imagery. The height difference between the headwall and the outflow of the slump into the Batagay river is 145 m along a distance of 2300m, while the slump maximum width is 800 m. Our analysis doesn’t show any signs of erosion slowdown along a headwall that is up to 86 m high. Comparison of the DEM with a reconstructed paleo-surface revealed that the slump has carved into the rolling topography to a depth of up to 73 m. The current size of the Batagay mega slump is >81 ha, while it had thawed >24.2 × 106 m³ of ice-rich permafrost through 2014. This huge amount of sediment released from the slump episodically dams up the Batagay river, forming a large temporary lake which then may discharge catastrophically. Geological on-site investigations and further geomorphometric analyses of this locality in conjunction with inter-annual and seasonal change detection observations will allow relating headwall retreat rates to local and regional controls on mega slump development and will help to identify potential areas susceptible to megaslump formation in non-glaciated regions. References Are, F.E., M.N. Grigoriev, H.-W. Hubberten, & V. Rachold (2005), Using thermoterrace dimensions to calculate the coastal erosion rate, Geo-Marine Letters, 25, 121-126. Grosse, G., L. Schirrmeister, C. Siegert, V.V. Kunitsky, E.A. Slagoda, A.A. Andreev & A.Y. Dereviagyn (2007), Geological and geomorphological evolution of a sedimentary periglacial landscape in Northeast Siberia during the Late Quaternary, Geomorphology, 89(1-2), 25-51. Kokelj, S.V., D. Lacelle, T.C. Lantz, J. Tunnicliffe, L. Malone, I.D. Clark & K.S. Chin (2013), Thawing of massive ground ice in mega slumps drives increases in stream sediment and solute flux across a range of watershed scales, Journal of Geophysical Research: Earth Surface, 118, 681-692. Kunitsky, V.V., I.I. Syromyatnikov, L. Schirrmeister, Yu.B. Skachkov, G. Grosse, S. Wetterich, & M.N. Grigoriev (2013), Ice-rich permafrost and thermal denudation in the Batagay area - Yana Upland, East Siberia, Kriosfera Zemli (Earth' Cryosphere), 17(1), 56-68. Lantuit, H., W.H. Pollard, N. Couture, M. Fritz, L. Schirrmeister, H. Meyer & H.-W. Hubberten (2012), Modern and Late Holocene Retrogressive Thaw Slump Activity on the Yukon Coastal Plain and Herschel Island, Yukon Territory, Canada, Permafrost and Periglacial Processes, 23(1), 39-51. Leibman, M., A. Gubarkov, A. Khomutov, A. Kizyakov & B. Vanshtein (2008), Coastal processes at the tabular-ground-ice-bearing area, Yugorsky Peninsula, Russia, in: Kane, D.L. and Hinkel, K.M. (eds), Proceedings of the Ninth International Conference on Permafrost, University of Alaska Fairbanks, June 29-July 3 2008, 1037-1042. Slagoda, E. A. (1991), Microstructure of permafrost slope deposits of the Kisilyakh Range, in: Melnikov, P.I. and Popov, A.I. (eds), Denudation in the cryolithozone, 19-29, Nauka, Moscow.

Permafrost, landscape and ecosystem responses to late Quaternary warm stages in Northeast Siberia S. Wetterich1, F. Kienast2, L. Schirrmeister1, M. Fritz1, A. Andreev3, P. Tarasov4 1Alfred Wegener Institute for Polar and Marine Research, Department of Periglacial Research, Potsdam, Germany; 2Senckenberg Research Institute and Natural History Museum, Research Station for Quaternary Palaeontology, Weimar, Germany; 3Institute of Geology and Mineralogy, University of Cologne, Germany; 4Institute of Geological Sciences, Free University Berlin, Germany Perennially frozen ground is widely distributed in Arctic lowlands and beyond. Permafrost responds sensitive to changes in climate conditions. Climate-driven dynamics of landscape, sedimentation and ecology in periglacial regions are frequently recorded in permafrost deposits. The study of late Quaternary permafrost can therefore reveal past glacial-interglacial and stadialinterstadial environmental dynamics. One of the most striking processes under warming climate conditions is the extensive thawing of permafrost (thermokarst) and subsequent surface subsidence. Thermokarst basins promote the development of lakes, whose sedimentological and paleontological records give insights into past interglacial and interstadial (warm). In this paper we present results of qualitative and quantitative reconstructions of climate and environmental conditions for the last Interglacial (MIS 5e, Kazantsevo; ca. 130 to 115 ka ago), the lateglacial Allerød Interstadial (ca. 13 to 11 uncal. ka BP), and the early Holocene (ca. 10.5 to 8 uncal. ka BP). The study was performed in course of the IPY project #15 ‘Past Permafrost’ with permafrost deposits exposed at the coasts of the Dmitry Laptev Strait (East Siberian Sea, East Siberia). The reconstruction based on fossil-rich findings of plants (pollen, macro-remains) and invertebrates (beetles, chironomids, ostracods gastropods). Interglacial vegetation dynamics are reflected in the pollen records by changes from early interglacial grass-sedge-tundra to shrub-tundra during the interglacial thermal optimum followed by grass-sedge-tundra vegetation at the end of the Kazantsevo warm period. Terrestrial beetle and plant remains prove the former existence of open forest tundra with Dahurian larch, grey alder and boreal shrubs interspersed with patches of steppes and meadows during the interglacial thermal optimum. Mean temperature reconstructions of the warmest month (MTWA, TJuly) for the interglacial thermal optimum are based on quantitative chironomid transfer functions revealed a TJuly of 12.9 ± 0.9 °C. The TJuly reconstructed by plant macrofossils amounts to 13.2 ± 0.5 °C, and the pollen-based TJuly reaches 14.3 ± 3.3 °C. Low net precipitation is reflected by steppe plants and beetles. The temperature reconstruction based on three independent approaches. Nethertheless, all methods consistently indicate an interglacial TJuly about 10 °C higher than today, which is interpreted as a result of a combination of increased insolation and higher climatic continentality during the last Interglacial. Grass-sedge dominated tundra vegetation occurred during the lateglacial to Holocene transition which was replaced by shrub tundra during the early Holocene. The presence of Salix and Betula pollen reflects temperatures about 4 °C higher than present between 12 to 11 uncal. ka BP, during the Allerød Interstadial, but shrubs disappeared in the following Younger Dryas stadial, reflecting a climate deterioration. Alnus fruticosa, Betula nana, Poaceae and Cyperaceae dominate early Holocene pollen spectra. Pollen-based reconstructions point to TJuly 4 °C warmer than present. Shrubs gradually disappeared from coastal areas after 7.6 uncal. ka BP when vegetation cover became similar to modern wet tundra. Thermokarst acted as response to warming conditions on landscape scale in permafrost regions. Concurrent changes in relief, hydrology and ecosystems are obvious and detectable by analyses of the paleontological record preserved in thermokarst deposits.