The Pleistocene termination in Northern Eurasia

Quaternary International, Vol. 28, pp. 105-111, 1995

Pergamon

Copyright © 1995 INQUA/Elsevier Science Ltd Printed in Great Britain. All rights reserved 1040-6182/95 $29.00

1040-6182(95)00042-9 THE PLEISTOCENE TERMINATION IN NORTHERN EURASIA A . A . Velichko

Institute of Geography, Academy of Sciences, Staromonetry 29, Moscow 109017, Russia

GLACIATION One of most important factors which exerted considerable influence on the Late Pleistocene climates and environments in Northern Eurasia, was glaciation (Fig. 1). Widely accepted was the hypothesis of a panarctic ice sheet covering Eurasian Arctic and Subarctic during the last glacial maximum, developed by Grosswald (1977). Recent results prove, however, that the Scandinavian ice sheet was the most expansive in the area under discussion (Velichko et al., 1994). Its southeastern boundary was along the Valdai Hills, and the eastern margin was in the Severnaya Dvina drainage basin. Individual lobes did not advance to their maximum simultaneously; the age of end moraines varies from 18 ka BP in the west of the Russian Plain to 21 ka BP in the middle section and to 24 ka BP in the east (Faustova, 1984; Faustova and Velichko, 1991; Velichko and Faustova, 1992).

Studies of marginal seafioor relief and sediments, according to Kaplin and Shcherbakov (1986), Biryukov et al. (1988) and Pavlidis (1992) and others, revealed distinct traces of the Scandinavian ice sheet on the Barents Sea shelf; fields of glacial deposits are clearly seen north of the Kola Peninsula to depths of 150-170 m. The ice margin here formed an ice shelf. Off the Murmansk rampart, the ice shelf merged into marine pack ice, which extended as far south as 60°N in the Atlantic Ocean. Outlet glaciers from Spitzberen and Svalbard joined the pack ice in the north. New data have been obtained on the Novaya Zemlya glaciation. Only Northern Island appeared to be completely covered by an ice dome during the last glacial maximum (LGM). Glaciers of Southern Island probably did not spread onto the shelf at that time, due to a lack of tills in the Pechora Sea (Lavrushin, pers. comm.). It is possible that the end moraines on the shelf off the Novaya Zemlya,

FIG. 1. Global glaciation at the Last Glacial Maximum.

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A . A . Velichko

at a distance of 100-150 km from the coastline, may correspond to an earlier stage of the glaciation. This assumption corresponds well with radiocarbon dates of end moraine formations in the northeast region of the Russian Plain; the age ranges from 33-42 ka BP. In light of the information above, it seems probable that the vast ice sheet, which centered at the Novaya Zemlya islands, expanded to its maximum (and covered the northeast of the Russian Plain) not at the LGM, but earlier - - at the Middle Valdai (Middle Weichselian) time. In any case, the radiocarbon dates indicate a considerable time gap between the maximum spread of the Scandinavian ice sheet and that of the Novaya Zemlya. Further to the east, mountain glaciers occurred at the Polar Urals; piedmont glaciers flowing onto the adjacent plains. As for the West Siberian Lowland, it was previously assumed that its northern part had been covered by an ice sheet centred at the Kara Sea shelf. However, later investigations of the geology and geomorphology of the Taz and Gydan peninsulas (Avdalovich and Bidzhiev, 1984) revealed the presence of peat layers and mammoth bones not overlain by tills and dated by radiocarbon to 40-15 ka BP. Recently, Astakhov (1987) critically revised the notions of vast ice-dammed lakes, presumably existing in West Siberia at the end of the Pleistocene. Data from Central Siberia disagree with the concept of the Kara ice sheet. Fossil glacier ice in the Yenisey valley (The Ledyanaya Gora section) appeared to be overlain by sediments older than 40 ka BP (Astakhov and Isayeva, 1985). In the northern Central Siberia, on the Taimyr Peninsula, lacustrine sediments not covered by till yielded a series of radiocarbon dates in the range of 30-11 ka BP (Isayeva, 1984). Only mountain glaciers existed there on the Byrranga Mountains. Small valley glaciers descended from the Norilsk Plateau. Studies of the glacial deposits in the region (carried out by Velichko) have shown rock fragments in tills to be of local provenance. Still farther to the north, on one of the Severnaya Zemlya islands (east of the Kara Sea), mammoth remains not covered by till have been dated by 14C to 24-19 ka BP; it seems that only small ice caps existed in the islands' interior (Makeev et al., 1979). Ice sheets of moderate dimensions also formed in Central Siberia, on the Putorana and Anabar plateaus. The northeast of Siberia contained mainly alpine glaciation (as shown by Bespaly and Glushkova; Velichko, 1987); the most extensive glaciation - ice fields and piedmont glaciers - - occurred in the Verkhoyansk Range. According to Laukhin, the glaciers were larger on the Chukchi Peninsula due to the Pacific influence. The available data on geology and geomorphology of the eastern Euasian Arctic suggest small ice cap occurrences on some islands. No evidence of an ice sheet has been found by the Russian-Canadian Joint Expedition in 1994 (Grinenko, Galabala, MacDonald, Cwynar and Velichko). Finally, Pavlidis (1992) has shown that most of the Bering Sea shelf was an alluvial plain during the Sartan glacial time. Alekseev reached a similar conclusion.

The amount of data does not confirm the notion of the Panarctic ice cover during the Late Pleistocene (Fig. 1). Local glacial systems prevailed over most of Northern Eurasia; the largest ice sheet was the Scandinavian. Ice sheet dimensions decreased steadily eastward, parallelling the regular increase in climate continentality which implied reduction of precipitation in that direction. Glaciation could have been more expansive during the first stage of the Late Pleistocene ice age (the Zyryanka glaciation). The rate of glacial retreat may be estimated primarily from the data on the Scandinavian ice sheet. The ice sheet's rate of retreat increased from the maximum stage to the final ones. The rate was not more than 30-40 km per 1000 years between 18 and 15 ka BP (the Bologoye-Vepsovo stages). It increased to 100-120 km per 1000 years between 15 and 13 ka BP (VepsovoLuga stages), and reached its maximum, 170-180 km per 1000 years, after 13 ka BP. Warming and ice sheet retreat proceeded step by step and was occasionally interrupted by short advances of the ice. It seems reasonable to assume that both the Allerod warming and the Dryas 3 cooling were within the general sequence of the oscillatory process, though the last microcycle (Allerod-Dryas 3) was most pronounced due to increase in temperature rise in Allerod; the cold spell of he Younger Dryas was conspicuous against the warmer background, though the range of the cooling was less than at previous cold stages.

PERIGLACIAL REGIONS

The last glacial maximum corresponds to the time when the Yaroslavl horizon of cryogenic structures was developed, which is the most pronounced of all the Pleistocene cryogenic horizons. The permafrost area reached as far south as latitude 45°N at that time (Velichko and Nechaev, 1994). Landforms developed within the cryolithozone were similar to those found in the Siberian region at present, except for the infrequent occurrence of pingos. Most important were systems of large polygons (up to a 20--40 m in diameter). As Timireva has shown (Velichko et al, 1994), cryogenic processes considerably affected the enclosing loess material. Radiocarbon dates indicate that the permafrost began to degrade at its southern margin ca. 17 ka BP. In some cases, however, a reactivation of the cryogenic processes was recorded after 12 ka BP, prior to the Holocene (according to radiocarbon dates). It may be assumed that cryogenic reactivation was related to the Younger Dryas cooling. The late glacial time featured widespread dune formation and active eolian processes. Vast dune fields were formed, primarily within alluvial basins, as far south as the middle reaches of the Don and Dnieper valleys. Data obtained by Drenova (Drenova, 1994; Drenova et al., in press) from the Oka drainage basin, suggest that the first phase of dune formation preceded

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Pleistocene Termination in Northern Eurasia

the Allerod and probably corresponded to the Boiling, while the principle phase was linked to the Younger Dryas cold stage. As indicated by parabolic dunes orientation, the dune forming winds were directed from the west and northwest; less common were southwestern winds.

CLIMATE Temperatures and annual precipitation values during the Allerod interstadial have been estimated by Klimanov (1994) on the basis of reliably dated palynological spectra primarily obtained from lacustrine sediments and peat deposits (Fig. 2). Analysis of mean July temperatures revealed significant negative deviations from the present-day values (by 3-4°C) in the northwest of the European Russia and in southern Siberia; the lower temperatures were probably due to the still considerable influence of the retreating ice sheet in the first case, and to the active Siberian anticyclone in the second. South of the Scandinavian ice sheet the deviations decreased steadily and were less than 1°C at latitude 50°N. Summer temperatures were close to modern values in mid-latitude Western and Central Siberia and became higher than at present northward. Most pronounced warming was reported from the coastal lowlands of the northern seas: Laptev, East Siberian and Chukchi seas; it could reflect the higher degree of climate continentality of the region during the Allerod, as the coastline considerably shifted to the north at that time. In the Far East, July temperatures 60"

70"

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were lower than today by 2-3°C; this was probably due to less active warm current. January temperature deviations from present values reveal a somewhat different pattern. In Eastern Europe near glacial ice, the winter temperatures were about 8°C below present values (the deviation value was twice that of the summer temperatures). Deviations decreased southward and were about I°C at latitude 50°N. In Central Siberia, near the city of Norilsk (lower reaches of the Yenisei River), winter temperatures were similar to those of today; farther south they became gradually lower with negative deviations up to 5°C in the south of West Siberia. Farther to the east, winters were colder than at present within the same regions that featured higher summer temperatures, for example, in the intracontinental areas and near the Arctic coast (where climate continentality increased due to the northward shift of the coastline). Winters along the Pacific coast were 6-8°C colder than at present; the difference increasing to 8-10°C away from the coast. Precipitation in the Allerod differed most conspicuously from the today's values in the northwest of the Russian Plain; total annual amount was up to 100 mm lower. The farther the distance from the ice sheet, the less the precipitation difference, and in the southeast of the Russian Plain and in southern Siberia, rainfall might have been somewhat higher than at present. Reconstructed characteristics of the Allerod paleoclimate suggest that the regional climates in Northern Eurasia were influenced not only by global processes

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FIG. 2. Paleoclimatic characteristics of the Allerod (deviations from present-day values). Black circles indicate points where paleoclimatic characteristics were reconstructed by the authors, open circles indicate the data taken from the literature. (a) Mean July temperature; (b) mean January temperature; (c) mean annual temperatures; (d) annual precipitation.

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TABLE 1. Deviations of temperatures (°C) and annual precipitations (mm) at about 10.5 ka BP from present-day values, calculated from palynologicaldata (location of sites shown in Fig. 2) Coordinates

Deviations of temperatures

No. July

January

Annual mean

Deviation of precipitation

-5 -5-6 -5-6 -6 -5-6 -5-7 -4-5 -6

-15 -15-16 -14-16 -14 -15-17 -13 -12-15 -15

-10 -10 -10 -8 -10-14 -8--10 -8--10 -11

-150 -150 -150 -200-250 -200 -200 -150-200 -150-200

-4

-6--7

--4-5

-75-100

Sudoble Chernikovo Stariniki Melikhovo Sitrfia Dutovo Nis/va Votkinsk Evbazy Gorbunovo Entarnoe Suzun Todzha Kotokel Norilsk Boyarka

-4 -3-4 -2 -5 -6 -3 -3 -4-5 -5 -4-5 -5 -11 -4-8 -6--4 -2 -2-3

-6--7 -6 -4 -10 -12-13 -6 -10 -11 9 -10-11 -7 -13 -12-14 -12 9 ?

-4 -4 -3 -8 -8-10 -6 -6--8 -6--8 -6 -8 -5-6 -10 -10-12 -10-11 9 ?

-50-100 -50-100 -50 -200 -200 -250-300 -300 -200 -200-250 -150 -150 -100-150 -200-250 -300-350 -0-50 ?

118 120 137

Markha Vilyui Kievka

-4 -3 -5-6

9 --6--7 -12

9 -5 -8

-150 -150

142

Uanda

-3

-8

-5-7

-150-200

N

E

Sites

1 2 3 4 5 6 7 8

62 61 64 64 61 59 56 58

33 32 38 43 29 25 23 27

Gotnavolok Diinnoe Tomitsa Seb-boloto Vuoksa Kunda Elgava Ostrov

9

54

27

Kobuzi

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

53 53 51 56 59 62 61 57 55 58 61 53 53 51 69 71

28 26 26 39 52 57 57 54 55 61 78 83 96 106 90 98

26 27 28

63 63 46

29

52

resulting in the warming, but also by still-existing ice sheets and considerably lower ocean levels. The thermal regime (heat supply) was higher during the Allerod than during the subsequent Younger Dryas, and isotherm pattens show noticeable regional differentiation. Characteristics of the coldest time during the Younger Dryas (approximately 10.5 ka BP) were calculated by V.A. Klimanov from palynological data on 29 localities (see Table 1); as in the case of the Allerod, spatial reconstructions were made for the coldest and warmest months and for total annual precipitation (Fig. 3). July temperatures during the Younger Dryas in comparison with the modern ones show considerable cooling I more than 6°C - - in the northwest, near the margin of the Scandinavian ice sheet. The negative deviations were presumably less than 4°C in the Siberian North, though no precise data are presently available. In southern Siberia, temperatures were as much as 10°C lower than at present. In the southwest of the Russian Plain, negative deviations did not exceed 4°C. The pattern of January isotherms for the Younger Dryas resembles that of July temperatures, except for higher deviations values. January was at least 140C colder than at present in the Eurasian northwest, about 6°C colder north of Siberia and more than 12°C colder in southern Siberia. A cooling, less than 60C, is recorded in the southwest of the Russian Plain.

The most pronounced differences in the total annual precipitation are in the northeast of the European Russia, where the amount is about 250 mm lower than at present. Lowered values of precipitation were found in the southern Central Siberia and Transbaikalian region (by about 200 mm), and in southern West Siberia (by 150 mm or less). Southwest of the Russian Plain and north of Central Siberia decreases in annual precipitation by about 100 mm were noted. A comparison between the Allerod warm phase and the Younger Dryas cooling shows that the range of temperature changes between the two phases was at a maximum for the whole late glacial time. When following temperature ranges along latitude 50°N, the least variance in temperatures from the Allerod to the Younger Dryas is found in the west (2-3°C); cooling increases eastward to 6-7°C in Western and Central Siberia and to 4-5°C near the eastern coast.

VEGETATION Analysis of the data available on the Allerod flora and vegetation carried out by Zelikson (1994), revealed a rather limited occurrence of tundra communities, which were restricted to the ice sheet periphery and the Kola Peninsula. The tundra coenoses were distinguished by

Pleistocene Termination in Northern Eurasia il

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b

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FIG. 3. Paleoclimaticcharacteristics of the Younger Dryas (deviationsfrom the present-day values). For explanations see Fig. 2.

the presence of steppe elements in plant communities, such as Artemisia, Helianthemum, Ephedra. A marked northward expansion of the forest-tundra was recorded in the northeast of Europe; birch, spruce and fir forests, in combination with tundra coenoses including Betula nana and Alnaster, reached as far as the northern sea coast. South of latitude 65--67"N, the area was forested (in addition to the flora data, it was confirmed by fossil entomofauna, which included forest beetles). The forests went south as far as 50-52"N; the forest/steppe boundary was farther to the south than at present. Most parts of the zone were occupied by spruce forests. In the west (Baltic region, western Byelorussia) pine was dominant and in the east, near the Ural mountains, larch was a dominant species (as a secondary component of forest coenoses it occurred much wider). In the south of the forest zone, pine forests formed a belt, with broad-leaved species in the south-west, near the Carpathians. During the Allerod interstadial, the forests differed from modern ones (although tree species were the same), they were similar to open woodlands and interspersed with herb coenoses, more-or-less steppelike in appearance (as suggested by the presence of Eurotia ceratoides, Kochia prostrata, Artemisia). Of equal importance were eryophytes, characteristically variouable in ecology: for example, dwarf birch, meadow mesophyte Selaginella selaginoides, and a water plant MyriophyUum alterniflorum. Heliophytes, species typical of disturbed ground (such as buckthorn, Helianthemum, Ephedra), and halophytes were also present. The heart of the flora, however, were the boreal species, as well as those featuring a broad range of occurrence with the boreal forests.

The late glacial en~,ironments in Western and Central Siberian Arctic were little different from the modern ones, as shown by Andreev and other researchers (Andreev et al., 1989; Velichko et al., 1994b). The arctic tundra occupied the northern Yamal Peninsula. Palynological and radiocarbon data obtained for the Sverdrup Island are indicative of the arctic tundra with patches of steppe vegetation both on the island and over the emerged Kara Sea shelf. Tundra and forest-tundra with larch existed on the Taimyr Peninsula. Foreststeppe (Artemisia steppe with isolated birch groves) was dominant south of the forest-tundra. Farther to the east, the Allerod was marked by northward spread of larch together with dwarf tree birch, and Alnaster; the bush tundra seems to have replaced the earlier arctic tundras. The central Yakutia featued steppe-type wormwood-grass coenoses, bush communities, and patches of larch and birch forests (Fig. 4). According to data obtained by Borisova (1994), changes in the flora and vegetation of Eastern Europe at the Allerod/Younger Dryas boundary manifested in forest area reduction a decrease in Picea in the forest coenoses. Steppe communities and those developed on open disturbed grounds and saline soils became more widespread. Concurrent cooling resulted in expansion of dwarf birch communities, though some cryophilic species sensitive to the climate continentality (such as Selaginella selaginoides) become more infrequent. The ecological, phytocoenotic and arealogical studies of the Younger Dryas fossil floras show that vegetation was very complex during this cold stage. Within the periglacial forest-steppe zone, it included the boreal forest, steppe, tundra, meadow phytocoenoses, the halophyte communities, and those with plants

110

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FIG. 4. Main coenotic plant groups in the Younger Dryas floras: I, Zharnovets site; II, Ponizovye site; III, group of site in the Moskow region; IV, Kikolovo site.

indicating open and disturbed soils conditions. In cold stages where herbaceous communities predominate, evidenced by high frequencies of non-arboreal pollen in the pollen spectra, micro- and nanorelief is important in determining plant association distribution; relief causes high variability in controlling ecological factors, such as insolation, snow depth, the thickness of the active layer, etc. The diversity of habitats is due to the cold. Continental climatic conditions existed in mid-latitudes, where the summer insolation was rather high. In spite of the superficial resemblance of the vegetation structure over the area, certain geographical tendencies can be traced; farther to the East, less tundra and swamp plants and more steppe types are found in the fossil floras. Of forest plants, the species of dark coniferous (taiga) forest are more abundant east of the European periglacial forest-steppe, while those of light coniferous forest prevail in its western part. Paleoflora data indicate that meadow communities were characteristic for the Younger Dryas vegetation. This can be explained by the wide tolerance of meadow plants to ecological conditions and their ability to respond quickly to climatic change. In West Siberia, the Younger Dryas was marked by an increase in tundra and steppe elements and a reduction of forest species. Xerophilic communities become more important in the north, particularly on the emerged shelf of the Kara Sea and Sverdrup Island. In Central Yakutia, the vegetation changed in a similar fashion, Artemisia-Gramineae communities expanding at the expense of bush and forest formations. The Younger Dryas cooling was distinct not only in Eastern Europe, but all over Northern Eurasia including the easternmost regions (as recorded in pollen spectras obtained from sites 28 and 29, Table 1). Therefore it cannot be attributed solely to the influence of cold meltwater on the North Atlantic. More likely it resulted from global factors similar to those that caused glaciations, though the range of the Younger Dryas cooling was considerably less.

The paleogeograhic reconstructions of the Younger Dryas environments indicate both highly dynamic evolution of the landscapes and their extremely wellpronounced differentiation during this cold stage which terminated the last glacial age. Drastic changes in climate at the end of the late glacial time resulted in the widespread occurrence of periglacial steppe communities; components of the latter were inherited from the glacial epoch and persisted within limited areas of favourable habitats. Forests and open woodlands, typical of Allerod, were considerably reduced in area during the Younger Dryas.

REFERENCES Andreev, A.A., Klimanov, V.A., Sulerzhitsky, L.D., and Khotinsky, N.A. (1989). Chronology of environmental and climatic changes in the Central Yakutia during the Holocene. In: Paleoclimates of the Late Glacial and the Holocene, pp. 116-121. (Eds A.A. Veliehko and N.A. Khotinsky). Nauka, Moscow. Astakhov, V.I. (1987). Origin of West Siberian Lakes. In: Palaeohydrology of the Temperate Zone, Vol. 1, pp. 144-155. Valgus, Tallinn. Astakhov, V.I. and Isayeva, L.L (1985). On the Radiocarbon age of the last glaciation in Lower Yenisey. Doklady AN SSSR, 283 (2), 438-440 (in Russian), Avdalovich, S.A. and Bidzhiev, R.A. (1984). Karga marine terraces in northern West Siberia and problem of Sartan glaciation. Izvestiya AN SSSR. Seriya Geographicheskaya, l, 70-73 (in Russian). Biryukov, V.Yu., Faustova, M.A., Kaplin, P.A., Pavlidis, Yu.A., Romanova, E.A., and Velichko, A.A. (1988). The Palaeogeography of Arctic shelf and coastal zone of Eurasia at time of the last glaciation (18,0O0 yrs B.P.). Paleogeogr. Paleoclimatol. Paleoecol., 68, 117-125. Borisova O.K. (1994). Paleogeographical reconstructions of the East-European forest-steppe in the Younger Dryas. In: Short-term

and Sharp Environmental-climatic Changes during the Last 15,000 Years, pp. 113-124 (Ed. A.A. Velichko). Institute of Geography RAS, Moscow (in Russian). Drenova, A.N. (1994). Reconstruction of paleo-wind activity from dune sand characteristics. In Wind-blown Sediments in the Quaternary Record, 5-8 January 1994. Abstracts. Royal Holloway University, London. Drenova, A.N., Timireva, S.N., and Chikolini, N.I. (in press). Late Glacial aeolian processes on the Russian Plain. Quaternary Int.

Pleistocene Termination in Northern Eurasia Faustova, M.A. (1984). Late Pleistocene glaciation of European USSR. In Late Quaternary Environments of the Soviet Union (Ed. A.A. Velichko), pp. 3-12. University of Minnesota Press, Minneapolis. Faustova, M.A. and Velichko, A.A. (1991). Dynamics of the last glaciation in northern Eurasia. Sveriges Geologiska Undersokning, Set. Ca $1, 113-118. Grosswald, M.G. (1977). The latest Eurasian ice sheet. In: Glaciological Studies: Chronicle and Discussions (Eds G.A. Avsyuk and V.M. Kotlyakov), pp. 45--60. USSR Academy of Sciences, Moscow. Isayeva, L.L. (1984). Late Pleistocene glaciation of North-Central Siberia. In: Late Quaternary Environments of the Soviet Union, pp. 21-300. University of Minnesota Press, Minneapolis. Kaplin, P.A. and Shcherbakov, F.A. (1986). Reconstructions of shelf environments during the Late Quaternary. J. Coast. Res., 3 (1), 95-98. Klimanov, V.A. (1994). Late Glacial climate in Northern Eurasia (the last climatic rhythm). In: Short-term and Sharp Environmental-Climatic Changes during the Last 15,000 Years. (Ed. A.A. Velichko), pp. 61-93. Institute of Geography RAS, Moscow. Makeev, V.M., Arslanov, Kh.A., and Garutt, V.E. (1979). The age of mammoth in Severnaya Zemlya and several questions of the Late Pleistocene paleogeography. Doklady AN SSSR, 245 (2), 1114-1118 (in Russian). Pavlidis, Yu.A. (1992). The Shelf of the World Ocean in the Late Pleistocene. Nauka, Moscow (in Russian). Velichko, A.O. (Eds.) (1987). Quaternary Glaciations on the USSR territory. Nauka, Moscow (in Russian).

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Velichko, A.A. and Faustova, M.A. (1992). Glaciation during the Last Glacial Maximum. In: Atlas of Paleoclimates and Paleoenvironments of the Northern Hemisphere (Eds B. Frenzel, M. Pecsi, and A.A. Velichko), pp. 101-103. Geographical Research Institute HAS, Gustav Fischer Stuttgart. Velichko, A.A. and Nechaev, V.P. (1994). Cryogenic processes within the Late Pleistocene periglacial zone of the Russian Plain and their imprint on the present-day landscape. In: Paleogeographical Basis of the Modern Landscapes (Eds A.A. Velichko and L. Starkel), pp. 82-86. Moscow, Nauka (in Russian). Velichko, A.A., Timireva, S.N., and Khalcheva, T.A. (1994a). Late Pleistocene loesses of periglacial areas of the Western Russian Plain. In: PaleogeographicalBasis of the Modern Landscapes (Eds A.A. Velichko and L. Starkel), pp. 63-69. Nauka, Moscow. Velichko, A.A., Andreev, A.A., and Klimanov, V.A. (1994b). Vegetation and climate dynamics during Late Glacial and Holocene in tundra and forest zones of Northern Eurasia. In: Short-term and Sharp Environmental-climatic Changes during the Last 15,000 Years (Ed. A.A. Velichko), pp. 4-60. Institute of Geography RAS, Moscow (in Russian). Velichko, A.A., Kononov, Yu.M. and Faustova, M.A. (1994c). The last glaciation in the Late Pleistocene. Prioroda, 7, 63-67 (in Russian). Zelikson, E.M. (1994). On the characteristics of the vegetation of Europe during the Allerod. In Short-Term and Sharp Environmental-Climatic Changes during the Last 15,000 Years, pp. 113-124. Institute of Geography RAS, Moscow (in Russian).