Surface Runoff to the Black Sea from the East European Plain During Last Glacial Maximum–Late Glacial Time

Home , Black Sea drainage basin, Suda (river), Sudost

Downloaded from specialpapers.gsapubs.org on September 18, 2012

The Geological Society of America Special Paper 473 2011

Surface runoff to the Black Sea from the East European Plain during Last Glacial Maximum–Late Glacial time

Aleksey Yu. Sidorchuk Andrey V. Panin Geographical Faculty, Moscow State University, Vorob’evy Gory, Moscow 119991, Russia

Olga K. Borisova Institute of Geography, Russian Academy of Sciences, Staromonetny per., Moscow 119017, Russia

ABSTRACT

Hydromorphological and hydroclimatic methods were used to reconstruct the former surface runoff from the East European part of the Black Sea drainage basin. Data on the shape and dynamics of the last Fennoscandian ice sheet were used to calculate meltwater supply to the headwaters of the Dnieper River. The channel width and meander wavelength of well-preserved fragments of large paleochannels were measured at 51 locations in the Dnieper and Don River basins (East European Plain), which allowed reconstruction of the former surface runoff of the ancient rivers, as well as the total volume of fl ow into the Black Sea, using transform functions. Studies of the composition of fossil fl oras derived from radiocarbon-dated sediments of various origins and ages make it possible to locate their modern region analogues. These analogues provide climatic and hydrological indexes for the Late Pleniglacial and Late Glacial landscapes. Morphological, geological, geochronological, and palynological studies show that the landscape, climatic, and hydrologic history of the region included: (1) a cold and dry interval close to the Last Glacial Maximum characterized by high meteoritic surface runoff supplemented by meltwater fl ow from ice-dam lakes; (2) a warmer humid interval at the end of the Late Pleniglacial with very high surface runoff and formation of extremely large meandering channels, combined with a short event of substantial infl ow from the Caspian Sea; and (3) a period from the Oldest Dryas to the Preboreal of nonsteady surface runoff decrease, and trans- formation of large meandering channels into smaller ones against the background of climate warming.

Sidorchuk, A.Yu., Panin, A.V., and Borisova, O.K., 2011, Surface runoff to the Black Sea from the East European Plain during Last Glacial Maximum–Late Gla- cial time, in Buynevich, I.V., Yanko-Hombach, V., Gilbert, A.S., and Martin, R.E., eds., Geology and Geoarchaeology of the Black Sea Region: Beyond the Flood Hypothesis: Geological Society of America Special Paper 473, p. 1–25, doi: 10.1130/2011.2473(01). For permission to copy, contact [email protected]. © 2011 The Geological Society of America. All rights reserved.

1 Downloaded from specialpapers.gsapubs.org on September 18, 2012

2 Sidorchuk et al.

INTRODUCTION sheet, changes in its volume and meltwater supply into adjacent rivers can be estimated (Kalinin et al., 1966). General information on the variability of climate and water Valuable information about past hydrological river regimes budget in Europe for the period from the Last Glacial Maximum can be derived from the morphology of the former river channels, (LGM), through Late Glacial time (LGT), and into the begin- especially if the former topography differs signifi cantly from ning of the Holocene (ca. 18–10 radiocarbon ka) is controversial. that of the present. Morphological data on the large Late Glacial According to vegetation reconstructions based on palynological paleorivers, which give distinct evidence of high surface runoff, data (Grichuk, 1982), the climate is believed to have been both were fi rst investigated by Dury (1964, 1965) in Western Europe cold and dry (the so-called cryoxerotic stage of the glaciation). and North America, and by Volkov (1960, 1963) in northern The climate of the southern part of the East European Plain drives Kazakhstan and western Siberia. Similar results were obtained changes in the water balance of southern sea and lake basins, for several rivers in the Black Sea basin: for the Seim (Borisova and, thus, most workers correlate the last major drop in the level et al., 2006) and Khoper (Sidorchuk and Borisova, 2000) Rivers of the Caspian Sea and Black Sea to the LGM (Varuschenko et in the Dnieper and Don basins; for the basin of the Danube River al., 1987; Winguth et al., 2000; Dolukhanov et al., 2008; and oth- in Hungary (Borsy and Felegyhazi, 1983; Kasse et al., 2000), ers). To explain such a dramatic drop in sea level, a substantial and in Romania (Howard et al., 2004). Morphological, textural, decrease in river runoff into the seas has been suggested. Var- palynological, and geochronological studies have shown that the uschenko et al. (1987) estimated annual river runoff into the Cas- LGT in Europe was a period of very large, widely spread river pian Sea during the LGM at only 20%–28% of its present value. channels, which presumably were formed by high and powerful Estimates of river runoff into the Caspian and Black Seas during surface runoff. the LGM based on atmospheric general circulation models com- Paleobotany plays an important role in providing data for prise 55% and 59% of the modern values, respectively (Kislov paleoclimatic reconstructions. Late Glacial climatic events and and Toropov, 2006). the chronology of vegetation development in Europe have been On the other hand, extensive dating of the Caspian deposits derived mainly from palynological data later dated through undertaken in the last decade have revealed a Late Glacial age radiocarbon and correlated with the isotopic “events” in the for the highest stage of the Khvalynian transgression (Svitoch Greenland ice-core record (e.g., Walker et al., 1999). To recon- and Yanina, 1997; Leonov et al., 2002; Chepalyga et al., 2008; struct the hydroclimatic conditions that existed at various stages and others), which suggests large surface runoff, at least from of the LGM and LGT, palynological studies of dated alluvium, the Volga River basin. Kalinin et al. (1966) estimated river runoff lake, and peat sediments can be applied. The use of paleobotanic into the Caspian Sea during the maximum stage of the Khvalyn- data for paleoclimatic and paleolandscape reconstruction implies ian transgression at 517 km3 per year, a fi gure that is 1.5 times that fl ora and vegetation are strongly infl uenced by changes in higher than the present value. Similarly controversial reconstruc- the natural environment and by the climate in particular (e.g., tions exist for the Black Sea drainage basin: some researchers Iversen, 1944; Grichuk, 1969). propose a relatively high runoff and a continuous outfl ow from This paper is aimed at (1) analysis of the paleoenvironmental the Black Sea (Lane-Serff et al., 1997), while others believe that conditions and causes for the paleohydrological changes in the the runoff into the Black Sea was low due to the dry climate, and East European part of the Black Sea basin during the LGM and as a result, sea level dropped to –110 m (Ostrovsky, 1982; Aksu LGT, (2) paleohydrological reconstruction of the surface runoff et al., 2002) or even to –150 m (Winguth et al., 2000) because there since the Late Pleniglacial, and (3) discussion of the land- of negative water budget during the LGM. It has also been sug- scape and surface runoff changes in the remaining part of the gested that a massive infl ow of meltwater from the Fennoscan- Black Sea basin during the last ~20,000 yr. dian ice sheet into the Black Sea took place after the LGM (Kva- sov, 1979; Kroonenberg et al., 1997), both directly through the METHODS Dnieper River valley and as an outfl ow from the Caspian Sea through the Manych Straight. A series of meltwater pulses is sug- Paleofl oristic Method of Paleolandscape and gested by isotopic depletion of the Black Sea waters between 18 Hydroclimatic Reconstruction and 15.5 ka (Bahr et al., 2006). Hydromorphological and hydroclimatic methods of paleo- Climate reconstructions usually rely on either the compari- geographic reconstructions allow quantitative estimation of the son of fossil and modern pollen assemblages and their associ- former surface runoff originating from melting glaciers and from ated modern climate, or selected indicator plant species with precipitation over a river basin. The ice volume of the Quaternary specifi c climatic requirements. Paleobotanical data used for such ice sheets can be reconstructed from their area using transform reconstructions are of two main kinds: plant macrofossils (seeds, functions derived from recent glaciological information and the- fruits, leaves, etc.), and pollen and spores. Macrofossils have oretical considerations about ice rheology (Markov and Suetova, the advantage of usually being identifi able to the species level. 1964; Khodakov, 1982; Peltier, 1994). Therefore, with informa- On the other hand, the occurrence of macrofossils is relatively tion on the age of the boundaries of the last Fennoscandian ice restricted, and they usually belong to aquatic and subaquatic Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 3

plants. Pollen diagrams provide more detailed information on characteristics within these analogues. Furthermore, the accuracy the history of specifi c plant taxa as well as vegetation on the of palynological analysis and the richness of a paleofl ora depend whole. Because plants sensitive to climatic conditions are mainly not only on the palynologist’s personal experience, but also on medium to low pollen producers, suffi ciently detailed pollen data the type of sediment, vegetation type, and the degree of pollen are essential. In the process of pollen identifi cation, the highest preservation. Late Glacial fl oras are usually relatively poor, so possible taxonomic resolution should be achieved to obtain the that not all analyzed samples provide suffi cient data for paleofl o- most complete results. This is possible if well-preserved pollen ristic reconstruction. of arboreal plants, as well as pollen and spores of certain groups Usually, conditions that are suitable for all the species of of herbaceous plants (e.g., Thalictrum, Lycopodium, Equisetum), a given fossil fl ora can be found within a comparatively small can be identifi ed to genus or even species levels. area. The present-day features of plant communities and the main Iversen (1944) was the fi rst to use the pollen of certain plant hydroclimatic indices of such a regional analogue would be close, species to estimate paleotemperatures. This author established in most cases, if not identical, to those that existed at the sampled the relationship between present occurrences of Ilex and Hedera site in the past. For example, fossil fl ora from the cultural layer and summer as well as winter temperatures. Such relationships at the Yudinovo Early Man site in the Desna River basin consists can be established by comparing the present boundaries of the of 19 plant species identifi ed using pollen analysis. At present, all plant’s geographical range (its “area”) and climatic data, i.e., the of them grow within a small area in the Biya River basin, down- coincidence of “area” limits and certain isotherms. For example, stream from Teletskoye Lake (Altai Mountains). Therefore, the Iversen showed that present-day ranges of Ilex and Hedera are current climatic characteristics of this region should be similar limited by the 0 °C and –2 °C January isotherms, respectively. to those of the Desna River basin at the time when the studied A well-known example of this kind is the coincidence of the tree paleofl ora existed (ca. 14–15 14C k.y. B.P.). line with the 10 °C July isotherm in many lowland and mountain areas. This approach has subsequently been extended by increas- Method of Estimating Ancient Continental ing the number of indicator species and climatic indexes consid- Ice-Sheet Volume ered (e.g., Hintikka, 1963; Zagwijn, 1996). Grichuk (1969) further developed Iversen’s approach into the mutual climatic range Analysis of recent continental and mountain glaciers shows method, in which as many species as possible are used to obtain that their shapes can be approximated by ellipses in both the hori- paleoclimatic estimates for a specifi c site. Their geographical zontal and vertical planes (Kapitsa, 1958): distributions are fi rst converted to climatic ranges, expressed as x2 y 2 climatic range diagrams (climatograms), and then their mutual =+ 1. (1) climatic fi eld is determined. Climatograms have the advantage b2 a2 that even plant species without present-day geographical overlap can be used for paleoclimatic reconstructions. Moreover, since Here, a is the half-length of the short axis of the ellipse in a this approach is based on the requirements of individual species, horizontal plane (in a vertical plane, it corresponds to the maxi-

ﬁ nding modern analogues for the fossil pollen spectra or plant mum height Hm of the glacier), and b is the half-length of a long assemblages is not necessary. axis (in a vertical plane, it is the distance from the glacier’s center

Grichuk (1969) suggested yet another method of climatic to its border Lm along a given transect), while x and y are corre- reconstruction based on paleoﬂ oristic data, elaborating on the sponding running coordinates from the ellipse’s center. The unit

idea of Szafer (1946–1947). This method consists of identify- volume Vu of a glacier’s vertical transect (for the unit width of a ing a modern region where all the species of a fossil fl ora grow glacier) is: presently. The mutual area of all individual species of a certain π fossil fl ora is found by overlapping their present-day “areas.” The =±ε VHLumm. (2) “areas” of as many plants as possible should be used. Geographi- 4 cal analysis of the modern spatial distribution of all the plants of a certain fossil fl ora (compilation of a so-called arealogram) allows Here, ε stands for the volume of initial relief of the glacier’s one to fi nd the closest modern fl oristic analogue to the past vege- base, which is neglected in the following equations. tation at the site. By identifying this modern regional analogue, it An empirical relationship exists between the maximum

is possible to determine the closest modern landscape and hydro- height Hm (in km) of modern sheet glaciers and the length of a

climatic environment to that of the fossil fl ora under study. short-axis transect Lm in km (Khodakov, 1982): Accuracy in these reconstructions depends on (1) the accuracy of the paleofl oristic defi nitions based on detailed pollen = analysis, (2) the richness of the resulting fossil fl oras, (3) the HkLmsm . (3) accuracy of the data on present-day geographical ranges of plants that represent components of the fossil fl oras, (4) the sizes of the According to the recommendations of Khodakov (1982), the

regional analogues, and (5) the variability of the hydroclimatic shape coefﬁ cient ks in this formula was 0.094 (with the scatter Downloaded from specialpapers.gsapubs.org on September 18, 2012

4 Sidorchuk et al.

from 0.075 to 0.12) for the last Fennoscandian glacier at the “cold” Methods of River Paleodischarge Estimation stage of its advance. For the “warm” stage of glacier retreat, he

recommends using a coeffi cient ks equal to 0.061 (0.048–0.077), The two main ways of calculating paleodischarge from which yields a fl atter glacier. For the stage of glacier retreat, the river channel morphology and texture are by either hydraulic or “dead-ice” glacier model also can be used, with “active” glacier regime equations, both fi rst used by Dury (1965). The advantages in the center and a marginal zone of melting “inactive” ice; this and disadvantages of these methods are discussed in Sidorchuk model follows from geomorphologic considerations (Chebota- et al. (2008). In the regime equations approach (used here), the reva and Faustova, 1982; Faustova, 1984). relationships between channel morphology and fl ow hydrology Therefore, in a short-axis vertical transect for two dated posi- must be known. Our investigation of the rivers on the Russian Δ tions of a glacier’s border with a lag t (yr) and with distances Lm1 Plain and in western Siberia (Sidorchuk et al., 2001, 2008) shows

and Lm2 (km), the unit rate of change in “cold” or “warm” glacier that it is important to use a broad range of river sizes and river ice volume (in km2 yr–1) is: basin landscapes to work out the empirical formula that suits the purposes of paleohydrological reconstructions. π−32 32 We used ~450 sections of rivers in northern Eurasia with ΔV ()kLs2 m2 kL s1 m1 u = . (4) mean annual discharge Q from 1 to 13,000 m3 s–1 and channel ΔΔtt4 a bankfull width Wb from 15 up to 3000 m, and the drainage basins were situated in a variety of landscapes from steppe to tundra. For the “dead-ice” glacier model, this unit rate of volume Based on these data, the relationship took the form: change is: 0.73 1.36 Qa = 0.012y Wb . (9) π−32 32 ΔVLL()kLs2 am2 kL s1 am1 − udm2dm1=+ Hd . (5) Parameter y is inversely related to the seasonal ﬂ ow variabil- ΔΔtt4 Δ t ity and represents the ratio between the mean annual discharge Qa

and the mean maximum discharge Qmax:

Here, Hd is “dead-ice” thickness, and indices “a” and “d” refer to

“active” and “dead” (inactive) parts of a glacier. y = 100(Qa/Qmax). (10) In the case of decrease in glacier volume, this unit rate would be negative and equal to the sum of the positive snow The range of parameter y is from 4 to 5 for rivers with high sea- accumulation rate I on the glacier’s surface and the negative sonal fl ow variability to more than 20 for those with low seasonal Δ Δ rate of meltwater drainage Wu/ t from the glacier plus snow- fl ow variability, and up to 100 for rivers with stable fl ow, such as ice evaporation rate E from the glacier’s surface. The unit rate of those draining large lakes. An increase in the fl ow variability (a water drainage for a unit width of the glacier (meltwater runoff in decrease in y) generally causes an increase in fl oodplain height km2 yr–1) would therefore be (here ice volumes are recalculated and fl ow concentration in a single channel with larger bankfull into water volumes with the coeffi cient 0.9): width. Flow variability depends on the basin area F (km2):

ΔΔWV0.9 y = aF 0.125. (11) uu=+−IE. (6) ΔΔtt Parameter a in Equation 11 reﬂ ects the geographical distribution of climatic ﬂ ow variability independent of river basin size.

The last two terms in Equation 6 are difﬁ cult to estimate for It can be calculated from measured mean annual discharge Qa,

Quaternary glaciers. Unit (for a unit width) snow accumulation mean maximum discharge Qmax, and basin area F. Parameter a rate I (in km2 yr–1) for recent sheet and mountain glaciers (Kho- typically varies between 1.5 for river basins with high seasonal

dakov, 1982) is related to their size Lm (km): ﬂ ow variability to over 4 for river basins with low variability. For paleolandscapes, parameter a for each paleochannel is estimated IkL= 23, (7) using recent ﬂ uvial analogues. It is then possible to calculate i m y for paleolandscapes with Equation 11, the mean annual dis-

and charge Qa from the paleochannel width with Equation 9, and the

mean maximum discharge Qmax with Equation 10. All variables ΔΔWVLL0.9 ⎛⎞23 + 23 uum1m2=+kE⎜⎟ −. (8) in Equations 9–11 can be obtained from maps and space images, ΔΔtti ⎝⎠2 as well as from Hydrological Service measurements. Estimation of coefﬁ cient a in Equation 11 for the past

Coeffi cient ki for recent glaciers varies in a broad range from requires knowledge of this relationship for the former landscape 0.001 to 0.005, and therefore its mean value of 0.00224 is recom- or its modern hydroclimatic analogue. Geographic infl uences on mended for use (Khodakov, 1982). river fl ow bring about similar hydrological regimes for rivers in Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 5 similar landscapes (Evstigneev, 1990). Geographic controls over drained by typical lowland rivers: 75% of the territory is situated at river ﬂ ow and their applications to paleohydrology lead to the the elevations less than 250 m above sea level (asl), and only 2% of principle of paleogeographical analogy (Sidorchuk and Borisova, the territory is at elevations above 500 m (in the south and southeast, 2000), which states that the hydrological regime of a paleoriver near the Crimean and Caucasian Mountains). The total length of the within a paleolandscape must have been similar to that of a permanent drainage net of 72,500 rivers in the East European part present-day river within the same type of landscape. Therefore, of the Black Sea basin is 344,258 km (Domanitskiy et al., 1971). the hydrological regimes of modern rivers in a certain type of The main part of the basin (74.7%) belongs to the Dnieper River landscape can be used to estimate the paleohydrological regime (504,000 km2) and the Don River (422,000 km2). All other rivers in the same type of paleolandscape. drain ~23.3% of the basin: the Dniester River (72,000 km2), the Southern Bug River (63,700 km2), the Kuban River (58,000 km2), STUDY AREA and other smaller rivers (together 120,000 km2). The large basin size, extending from ~57°N to 44°N, and General Characteristics of the Black Sea Drainage Basin from 23°E to 41°E, incorporates substantial climate and land- within the East European Plain scape variability. Mean annual temperature increases from 3 to 9 °C north to south, while annual precipitation decreases from The Black Sea drainage basin covers the area of ~1,240,000 km2 600 to 300 mm in the same direction. Surface runoff decreases and occupies ~40% of the East European Plain (Fig. 1). The basin is from 200 to 10–20 mm from the north to the south, and then

Figure 1. The East European part of the Black Sea drainage basin. Key: (1) river basin boundaries; (2) region boundaries (see the text for region descriptions); (3) data sites with large paleochannel remnants. Downloaded from specialpapers.gsapubs.org on September 18, 2012

6 Sidorchuk et al. increases again in the southern mountains. The main part of the The recent annual ﬂ ow of all the rivers to the Black Sea from basin, including the Dniester River basin, the northern parts of the East European Plain is ~110 km3 (83 km3 from the Dnieper the Dnieper and Don basins, and the Kuban River basin, would and Don Rivers) or ~30% of the runoff from the total drainage be covered with broad-leaved forest under natural conditions. The area of the sea. The water regime of the large rivers has been sub- lower Dnieper and Don basins would be covered by forest-steppe stantially changed by the construction of a system of hydroelec- and steppe vegetation under natural conditions. Now, ~70% of tric dams with large reservoirs. Small rivers are often regulated the basin is plowed and used for agriculture. by chains of ponds.

Figure 2. The region with the late Valdai (late Weichselian) glacial and periglacial features. Key: (1) deposits of proglacial lakes; (2) sandy ﬂ uvioglacial deposits; (3) meltwater blow-out channels; (4) present-day direction of ﬂ ow; (5) boundaries between ice sectors. Boundaries of the Last Glaciation stages and keys 1 and 2 are after Faustova and Chebotareva (1969). Key 3 is after Kvasov (1979) with corrections based on space images. Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 7

Main Geomorphologic Regions in the Black Sea Basin

The main geomorphologic features used in hydromorpho- )

1 t logical reconstruction belong to (1) glacial and periglacial topog- – / Δ u yr 3

raphy (as well as glacial and periglacial deposits), which allows W Δ one to trace the boundaries of the former sheet glaciers on the (km East European Plain, and (2) ﬂ uvial topography (with ﬂ uvial t ) 1 Δ – / deposits), which can be used for former runoff estimates. These u V yr 3 42 2 26 7 68 3 Δ 26 65 35 96 54 115 17 55 10 34 features, dated to the LGM and LGT, can be found within three 16 40 (km regions of the Black Sea basin (see Fig. 1). 0.9 ) 1 –

Region I with the Late Valdai (Late Weichselian) Glacial and yr E 3 Glaciofl uvial Features Glacial and periglacial topography and deposits of the Fen- (km ) 1 noscandian ice sheet in the Dnieper River basin were investigated – yr I 3 55 15 86 25 34 10 34 10 86 25 86 25 55 15 55 15 mainly in 1960s and 1970s, when several large monographs were 34 10 published (Gerasimov, 1969; Chebotareva and Makarycheva, (km 1974). The position of the southern boundary of the Fennoscan- dian ice sheet here during the LGM has been generally con- t Δ (yr) 1800 1200 1800 1800 1800 1200 1200 1800 fi rmed by recent works (Velichko et al., 2004; Svendsen et al., 1800 2004). It is fi rmly established that during its maximum extent, the last ice sheet covered only the northernmost part of the Upper

cal

Dnieper River basin (region I in Figs. 1 and 2). Glacial topog- t

raphy is represented by a system of moraine hills and ridges B.P.) (yr often clearly bordering the former ice lobes. Three main bands 14 of such moraine morphology, dated with C and pollen analy- m H

sis of under-moraine deposits, show the position of the glacier (km) boundary (Fig. 2) during the Bologoye/Brandenburg stage (ca. 18 14C k.y. B.P.), the Edrovo/Frankfurt stage (ca. 17 14C k.y. B.P.), and the Vepsovo/Pomeranian stage (ca. 15.5 14C k.y. B.P.)—all F the dates are after Chebotareva and Makarycheva (1974), the last (km) being entirely beyond the Black Sea basin. Taking the center of the southern half-ellipse of the Fennoscandian glacier at the cen-

ter of the northern part of the Gulf of Bothnia, the distance (Lm) to f L

the glacier border (at the headwaters of the Berezina River) was (km) ~1230 km at the Bologoye stage, ~1180 km at the Edrovo stage, and ~1100 km at the Vepsovo stage (Table 1). Each stage was

characterized by an “active” phase of the glacier advance and by L an “inactive” phase of the glacier retreat, when a marginal zone (km) of “dead-ice” could exist. Another important morphological and depositional feature is represented by the ﬂ uvioglacial plains formed by ﬂ uvioglacial streams, terraces, and deposits of ice-dam lakes and river ter- Edrovo 1180 270 160,000 0.5 20,300 0.5 160,000 270 Edrovo 1180 Edrovo 1180 670 390,000 3.2 20,300 20,300 3.2 3.2 390,000 24 670 260,000 83 440 Edrovo 1180 Edrovo 1180 Edrovo 1180 270 160,000 3.2 20,300 3.2 160,000 270 Edrovo 1180 Edrovo 1180 440 260,000 2.1 20,300 2.1 260,000 440 Edrovo 1180 Edrovo 1180 440 260,000 0.5 20,300 0.5 260,000 440 Edrovo 1180 Edrovo 1180 670 390,000 2.1 20,300 2.1 390,000 24 670 83 Edrovo 1180 Edrovo 1180 270 160,000 2.1 20,300 2.1 160,000 270 Edrovo 1180 14 20,300 0.5 390,000 24 670 83 Edrovo 1180 Vepsovo 1100 440 245,000 3.1 18,500 3.1 245,000 18,500 440 3.1 Vepsovo 1100 15 150,000 53 270 Vepsovo 1100 33 9 18,500 2.0 150,000 270 Vepsovo 1100 33 9 18,500 0.5 245,000 18,500 440 0.5 Vepsovo 1100 15 150,000 53 270 Vepsovo 1100 33 9 Vepsovo 1100 440 245,000 2.0 18,500 2.0 245,000 440 Vepsovo 1100 15 53 Bologoye 1230 670 410,000 3.3 21,500 3.3 410,000 670 Bologoye 1230 Bologoye 1230 670 410,000 2.1 21,500 2.1 410,000 670 Bologoye 1230 races related to them. These features are also dated with C and 21,500 0.5 410,000 670 Bologoye 1230

by their correspondence to the glacial topography. According to Ice-sheet stage Faustova and Chebotareva (1969) and Chebotareva and Makary- cheva (1974), the “glacial” part of the Black Sea drainage basin achieved its maximum area during the Bologoye (Brandenburg) stage ca. 18 14C k.y. B.P. At that time, a chain of ice-dam lakes (Kvasov 1979), or a series of short-lived glacial lakes (Mangerud See explanations of the indexes in the text. Note that all unit rates are multiplied on the sector half-width. B+C A+B+C B+C B+C C C A+B+C A+B+C C TABLE 1. MELTWATER SUPPLY TO THE DNIEPER RIVER HEADWATERS DURING THE EARLY STAGES OF THE FENNOSCANDIAN ICE-SHEET RETREAT

et al., 2004), formed a broad band between the glacier front and Note: “Dead-ice” glacier scenario “Warm” glacier scenario the main pre–last glaciation water divide of the East European drainage Sector of from ice sheet “Cold” glacier scenario Plain. The chain of lakes stretched from the headwaters of the Dnieper River in the east to the upper part of the Neman River Downloaded from specialpapers.gsapubs.org on September 18, 2012

8 Sidorchuk et al.

basin in the west (Fig. 2). The lakes were connected by channels provide the possibility of analyzing the general distribution of and formed a pool-step system with a general slope from east to such features. west. Mangerud et al. (2004) did not assume any southward melt- Remnants of the large alluvial paleochannels are well- water drainage from these lakes. Nevertheless, there is clear geo- preserved in the basins of the tributaries of the Dnieper and Don morphic evidence of meltwater blow-outs through a number of rivers (region II in Fig. 1). These remnants are mainly situated river valleys. During the Bologoye stage, when this lake system at the level of the modern fl oodplain. In the north, the necks was separated from the marginal valleys in the Polish and German of paleomeanders form fragments of the fi rst terrace, while the lowlands, the meltwaters drained to the south through the lowest point bars and fi lled paleochannels constitute the fl oodplains of parts of the main water divide. At different times, the fl ows used the recent valleys. In several river valleys, the paleochannel frag- different passes, so that a complicated pattern of blow-out valleys ments are partly situated at the low terraces and partly included was formed at the headwaters of the Dnieper, Dvina, and Neman within the recent fl oodplain. In the southern part of the region, all Rivers. Kalicki (1995) even suggested a new “Dnieper-type” of elements of paleochannels are included within the recent fl ood- paleochannel with multiple old valleys. On the whole, there were plains. Therefore, rivers in this region are characterized by very three main routes of meltwater drainage: through upper Dnieper high ratios of fl oodplain to channel widths. valley, through the upper Berezina River, and through the Pripyat The relationships between river channel plan geometry and River, each corresponding to one of three sectors of the ice sheet fl ow discharge are of prime importance for paleohydrological (A, B, C in Fig. 2). At that time (ca. 17 14C k.y. B.P.), the fi rst ter- reconstruction. The large paleochannels (in terms of their width race in the Upper Dnieper basin was formed (Kalicki and San’ko, and meander wavelength) were up to 15 times larger than the 1992). This terrace is ~1800 m wide in the Upper Dnieper valley, recent channels in the same river basin. Such sizes indicate large ~1200 m wide in the Upper Berezina valley, and ~1600 m wide surface runoff at the time of paleochannel formation. in the valley of the Shara River—a tributary of the Neman River Two key sites were investigated in this region: one in the that connected a paleolake at the Upper Neman basin with the Dnieper River basin (Seim and Svapa Rivers), and the other in Pripyat River valley (Fig. 2). The sizes of large meanders in these the Don River basin (the Khoper River). paleochannels correspond well to their widths. With the last Fennoscandian glacial retreat from the bound- Paleochannels in the Seim and Svapa River Valleys aries of the maximum (Bologoye) stage, the area of the addi- (Dnieper River Basin) tional “glacial” part of the Black Sea basin (F) decreased from The fl oodplain of the Seim River and its main tributaries is 410,000 km2 (sectors A + B + C) to 260,000 km2 (sectors B + C), characterized by a sequence of arcs with their radii of curvature

as the width of the ice-sheet front (Lf) was reduced from 670 to exceeding that of the modern river channel bends by an order of 440 km (see Table 1). It happened when the paleo–Upper Neman amplitude (Figs. 3 and 4). Systems of natural levees and large River became connected with the marginal valleys in the Pol- abandoned oxbows are well defi ned on aerial photographs. Sys- ish and German lowlands through the Neman paleovalley, and tems of levees and hollows with relative relief of 0.5–1.5 m refl ect meltwater fl ow into the Pripyat River stopped. The meltwater steeply curved meandering paleochannels with wavelengths of fl uvioglacial streams and ice-dam lakes continued to drain into 3.3–6.5 km and widths of 350–700 m (for the recent Seim River, the Upper Dnieper and Upper Berezina only in the eastern part these are 0.2–1.0 km and 20–100 m, respectively). The fl ood- of the system. During the Edrovo stage, the area of the additional plains with remains of large paleochannels lie largely at 2.0– “glacial” part decreased again, from 260,000 km2 to 150,000 km2 2.5 m above low water level (LWL) and usually become inun- (sector C), when meltwater drainage into the Upper Berezina dated during fl oods. Only the tops of the highest levees are as River stopped. After the Dvina River valley formed during the high as 3–3.5 m and usually remain above fl ood level. Vepsovo stage, the entire system of meltwater drainage shifted The investigated fragment of the large paleochannel of the into the Baltic Lake and into the western marginal valleys, so that Seim River near Kudintsevo village is the highly curved mean- the Black Sea lost its connection with the meltwater source. der with a wavelength of 6 km. The texture of infi lling of this large paleochannel was investigated by coring along the profi le Region II with the Late Glacial Large Alluvial Paleochannels A′–A″ in the upper part of the bend (Fig. 3). The paleochannel Well-preserved fragments of large meandering paleochan- cross section has an asymmetrical triangular shape with the deep- nels can be distinguished on large-scale maps and space images. est part (~10 m below LWL) near the steep concave bank of the In our former investigations, 16 such fragments over rivers paleomeander. The paleochannel fi ll includes three main units. >200 km long were described in the Black Sea basin (see table The lowermost unit is fi ne silty sand 5–7 m thick, which belongs 1 in Sidorchuk et al., 2001). The use of Landsat-7 images with to the initial stage of the paleochannel infi ll. This sand is overlain 15 m resolution allowed us to fi nd an additional 35 fragments by gray clay and silt accumulated largely in the oxbow lake on within river valleys with basins greater than 5000 km2 (Table the fl oodplain. Deposits at the base of this unit were radiocarbon 2 in this paper). Although a future increase in image resolu- dated to 12,630 ± 70 and 13,800 ± 85 yr B.P., based on bulk tion will potentially increase the number of large paleochannels organic matter (samples Ki-6985 and Ki-6984). We assume that traced, currently available data on the Black Sea drainage basin the latter date indicates the time shortly after the macromeander Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 9

TABLE 2. PALEORUNOFF RECONSTRUCTIONS BASED ON THE SIZES OF LARGE ALLUVIAL PALEOCHANNELS IN THE BLACK SEA DRAINAGE BASIN CA. 14–15 14C k.y. B.P. Latitude Longitude F λ W Q X River 2 3 (°N) (°E) (km ) (m) (m) (m /s) (mm) radiA 10.94 69.83 5107 548 471 84 612 anizereB 20.45 78.82 7559 199 062 47 542 guitiB 30.15 60.04 5967 7711 112 96 282 Buzuluk (Khoper) 50.64 42.79 6390 1206 182 62 307 anseD 31.15 30.13 381,48 5412 583 491 27 anseD 44.15 59.13 541,17 6081 872 631 06 anseD 54.25 65.33 989,42 3151 792 511 541 repeinD 79.45 89.23 0437 7991 631 385 kylrogE 99.54 03.14 022,11 839 05 241 kylrogE 78.54 04.14 7078 548 171 84 571 'tupI 74.25 93.13 0049 908 14 631 avtilaK 24.84 69.04 041,01 508 331 04 421 repohK 72.15 33.24 923,91 6091 823 041 822 repohK 64.25 76.34 1898 8531 481 17 842 Medveditsa (Don) 50.19 43.73 29,612 1810 213 107 114 Medveditsa (Don) 51.44 44.86 7582 973 184 55 229 assureN 44.25 09.33 6435 098 902 65 823 'lerO 79.84 94.43 8519 5621 781 86 332 'lerO 39.84 95.43 8519 379 302 06 702 'lerO 61.94 39.43 6747 219 251 64 491 'lerO 31.94 21.53 3565 297 351 14 922 lesP 32.94 86.33 851,22 3021 251 26 98 lesP 47.94 87.33 296,41 148 261 94 401 lesP 81.05 79.33 537,11 217 221 53 49 lesP 65.05 44.43 7149 176 121 33 011 lesP 40.15 22.53 7856 076 03 641 'soR 94.94 84.13 120,11 1073 854 762 367 laS 33.74 43.14 325,02 2931 882 501 161 Samara (Dnieper) 48.64 35.37 19,903 1936 286 130 205 mieS 93.15 14.33 070,72 8391 432 811 831 mieS 82.15 88.33 752,22 2061 022 79 731 mieS 84.15 87.43 876,91 3761 213 421 991 mieS 96.15 32.53 814,11 4291 943 041 783 Severskiy Donets 49.33 36.84 18,706 742 152 44 74 conS 66.15 46.13 1828 1132 761 736 hzoS 53.25 59.03 633,93 3961 083 451 421 hzoS 68.35 08.13 0366 522 77 463 'rytS 77.05 43.52 1027 2671 411 005 aluS 56.94 17.23 900,81 5951 362 601 681 aluS 26.94 88.23 900,81 2661 272 211 591 aluS 18.94 09.23 592,51 7271 091 19 881 aluS 22.05 23.33 8906 0621 832 77 693 asreT 78.05 11.44 9856 369 171 15 542 jadU 12.05 67.23 9756 4021 012 96 923 aihcloV 11.84 70.63 7269 177 931 04 031 anoroV 87.15 73.24 647,21 4341 252 39 032 alksroV 00.94 61.43 334,41 3921 652 98 491 alksroV 40.94 33.43 334,41 6121 832 18 771 alksroV 94.94 85.43 421,11 838 511 83 701 alksroV 37.94 36.43 9219 9521 702 27 942 alksroV 41.05 47.43 0226 957 331 73 581 Note: F—catchment area, λ—mean paleomeander step (half-wavelength), W—mean paleochannel width, Q—mean annual discharge, X—mean annual runoff depth.

was abandoned. By the beginning of the Holocene, the oxbow 0.6 km and 15–60 m, respectively). The paleochannel fragment lake had been transformed into a fen, and mineral deposition was near Semenovka village is clearly expressed in the modern topog- followed by peat accumulation. The thickness of the peat layer raphy (Fig. 4). Its surface lies only 4 m above the modern LWL, is up to 2 m. so that it is submerged during high fl oods. Coring reveals that In the Svapa River valley, the paleochannel formed steeply the channel trough assumes a box-shaped profi le. The top of the curved meanders with a mean wavelength of 2.8 km and a mean lower layer of fi ne- and medium-grained channel alluvial sands width of 300 m (for the recent Svapa River, these are 0.14– lies 1.5–2.5 m below the modern LWL. Silt and clay deposits Downloaded from specialpapers.gsapubs.org on September 18, 2012

10 Sidorchuk et al. with lenses of clayey sand fi ll the trough. Accumulation of fi ne- thickness of their subsequent infi lling varies at different parts of grained sediments began because of the abandonment of the the paleochannel. The system of channels that follows the right paleochannel in the Oldest Dryas (14,030 ± 70 yr B.P., Ki-6997), bank of the valley has been rarely fl ooded after it was abandoned, and continued during the Bølling and the Allerød (12,360 ± so that the former bottom of the paleochannel is locally exposed. 110 yr B.P., Ki-6999 and 11,755 ± 80 yr B.P., Ki-6996). At the end The maximum thickness of the channel-fi lling deposits there of the Late Glacial to beginning of the Holocene, the paleochan- does not exceed 1.5–3.0 m (Fig. 5). There are large eolian dunes nel almost entirely dried up, and the rate of deposition became on the terrace at the macromeander neck. The system of channels very low. Peat formation started in the late Preboreal (9120 ± along the left bank of the valley is situated nearer to the present 70 yr B.P., Ki-6995; 9300 ± 120 yr B.P., GIN-11951). river. The pools of the large paleochannel with maximum depth of 9–11 m were completely fi lled in by fi ne-grained alluvium, Paleochannels in the Khoper River Valley (Don River Basin) beginning from 11.3 to 10.8 14C k.y. B.P. One of the best preserved systems of large paleochannels A system of smaller paleochannels (although still larger than with bankfull channel width of 0.8–1.4 km, maximum depth of the recent Khoper River channel) was preserved at the outspread 9 m, and mean wavelength L of 5 km, is found on the ancient of the fl oodplain in the valley bend (see Fig. 5, cross-section fl oodplain of the Khoper River near Povorino (Fig. 5). At pres- C–C′). The channel width was ~200 m, and the meander wave- ent, the Khoper River near Povorino has a channel width of 60 length was ~1200 m. These channels were active before Boreal m, maximum depth of 4 m, and a meander length up to 360 m. time, presumably during the Younger Dryas. Radiothermoluminescence dating (Vlasov and Kulikov, Deposition of fl oodplain sediments during the Holocene was 1988) of the bottom deposits (17 ± 4 ka, RTL-808) shows that concentrated in a narrow belt, 1 km wide, along the river channel, the large paleochannels were formed during the Late Glacial. The where sandy natural levees up to 3.5 m above LWL were formed.

Figure 3. Geological section and space image across the large meandering channel of the paleo–Seim River near Kudintsevo village. Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 11

Region III with Large Incised Paleochannels (Fig. 6). At three of them, palynological studies were conducted Region III (see Fig. 1) occupies the high western part of the on fl uvial sediments that fi lled segments of large paleochannels East European Plain (Volyno-Podolsk Upland), the near–Black found on the fl oodplains of the Seim, Svapa, and Khoper Rivers Sea plain, and pre-Caucasus highlands. Rivers are often incised (Sidorchuk and Borisova, 2000; Borisova et al., 2006). Another here, presumably because of tectonic uplift. The channels of of the localities is the Early Man site of Yudinovo, where loamy these rivers form large bends with systems of Quaternary ter- sediments containing a Late Paleolithic cultural layer were sub- races at their necks. The ages and origins of these large bends are jected to detailed pollen analyses (Borisova and Novenko, 1999). mostly unknown, and their paleohydrological signal is unclear. One more fossil fl ora includes both pollen and plant macrofos- These features are not used in further runoff estimates. sils identifi ed in the so-called “Usvyacha” deposits exposed in several outcrops within the Dvina River valley near the villages RESULTS OF THE ESTIMATES OF of Sloboda and Drichaluki (Velichkevich, 1982; San’ko, 1987). PALEOGEOGRAPHIC CONDITIONS In the course of pollen analysis, an attempt was made to achieve the highest possible taxonomic resolution. Pollen identifi cations Hydroclimatic Parameters of River Development since have been made to species or genus levels for arboreal plants the Late Pleniglacial as well as certain groups of herbaceous plants. When identifi cations were possible only to the family level, the fi nds in question To reconstruct the main climatic indexes in the Black Sea were not included in the resulting lists of fossil fl oras (Table 3). basin, composition of fossil fl oras derived from palynological data On the whole, these paleobotanical data proved to be suffi cient (the method of “arealograms”) was analyzed. Fossil fl oras used to locate modern geographical analogues to 12 fossil fl oras and, for paleoclimatic reconstructions were derived from fi ve sites therefore, to estimate climatic changes that occurred within the

Figure 4. Geological section and space image across the large meandering channel of the paleo–Svapa River near Semenovka village. Downloaded from specialpapers.gsapubs.org on September 18, 2012

12 Sidorchuk et al. Figure 5. Geological sections and space image across the large meandering channels of the paleo–Khoper River near Povorino. RTL—radiothermoluminescence. near Povorino. meandering channels of the paleo–Khoper River Figure 5. Geological sections and space image across the large Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 13

Figure 6. Location of the modern region analogues to the Last Glacial Maximum and Late Glacial time fossil fl oras. Key: (1) key sites (Sm— Seim, Sv—Svapa, Kh—Khoper, Yu—Yudinovo, Sl—Sloboda/Drichaluki); (2) modern region analogues of the fossil fl oras (number of a fossil fl ora and its 14C age in k.y. B.P.); (3) corresponding hydrological region analogues in the lowland areas (A—Bol’shezemel’skaya Tundra, B— Lena Plateau).

East European part of the Black Sea drainage basin since ca. 18 which at present grow in various European and west Siberian tun- 14C k.y. B.P. dra and forest-tundra communities, along with some xerophytes The accuracy of the match between a modern geographical tolerant to low winter temperatures, such as Ephedra distachya. It analogue and a fossil fl ora depends not only on the richness of also includes trees and shrubs growing presently in regions with the latter, but also on the knowledge of the modern geographical cold and highly continental climate, mainly in Siberia (Larix sp., distribution of each plant genus or species. In some cases, the Alnaster fruticosus). Such a complexity of fl ora is highly typi- area of a region analogue remains rather large and includes dif- cal of the glacial fl oras in northern Eurasia (Grichuk, 1969). The ferent types of vegetation associations. Therefore, in this study, region currently inhabited by the species of fossil fl ora 1 lies south all such regions were located on the map (see Fig. 6) and addi- of the East Sayan Mountains, in the upper part of the Oka River tionally checked afterward against the types of plant communi- basin. The area has a cold climate with mean January air tem- ties, reconstructed from the pollen assemblage of a given sample. perature of –21 to –22 °C and mean July air temperature of 8– Sometimes, such comparisons enabled us to reduce the area of 10 °C, which are characteristic of mountain tundra in this region. the region analogue, but even then, the resulting areas remained Because of permafrost, the runoff coeffi cient should be very high large enough to show a substantial variability of hydroclimatic (more than 0.8). The mean annual precipitation is 400–600 mm, characteristics within them. The reconstructed ranges of climatic and the calculated runoff depth is 350–500 mm (Table 4). parameters are shown in Figure 7 as shaded boxes, their verti- The Early Man site of Yudinovo is located on the fi rst ter- cal size corresponding to the time intervals characterized by each race of the Sudost’ River, a tributary of the Desna River in the fossil fl ora. Dnieper basin. Both the geomorphological position of the site The earliest fossil fl ora (fl ora 1 in Table 3 and in Figs. 6 and and a series of radiocarbon dates based on the materials from the 7)—derived from the palynological and plant macrofossil stud- cultural layer indicate that the site was inhabited approximately ies of the Sloboda and Drichaluki sections—belongs to the rela- from 14.5 to 14 ka (Svezhentsev, 1993). According to palynolog- tively cold stage of the Late Pleniglacial, dated by radiocarbon to ical data, fossil fl ora of this interval consists mainly of forest and ca. 17–18 ka (Velichkevich, 1982; San’ko, 1987). The fl ora meadow plants. It includes Boreal and Arctic-Boreal trees and includes several of the typical Arctic and Arctic-mountain species, shrubs, forest club-mosses (Lycopodium clavatum, L. selago, and Downloaded from specialpapers.gsapubs.org on September 18, 2012

14 Sidorchuk et al.

TABLE 3. THE LATE GLACIAL AND THE HOLOCENE PALEOFLORAS FOUND IN THE BLACK SEA DRAINAGE BASIN

Site names: Sloboda/ Yudinovo Seim Seim Svapa Seim Khoper Seim Svapa Svapa Svapa Svapa Drichaluki Numbers of fossil ﬂ oras: Fl 1 Fl 2 Fl 3 Fl 4 Fl 5 Fl 6 Fl 7 Fl 8 Fl 9 Fl 10 Fl 11 Fl 12 Radiocarbon ages of the fossil ﬂ oras (k.y. B.P.)#: (17–18) (14–14.5) 13.8 12.6 12.4 12.2 11.9 11.5 (10.5) 9.8 7.5 4.9 I. Trees and shrubs (a) Micro- and mesothermal species of the continental regions Abies sibirica ** Alnaster fruticosus *† *** * Larix sp. **§ ** Pinus sibirica ***** (b) Species with broad ecological tolerances Betula alba * * ********** Betula humilis **** *** ** Picea abies * * ******* * Pinus sylvestris * * ********** (c) Relatively thermophile mesophytes Acer tataricum * Alnus glutinosa ** A. incana ***** *** * Corylus avellana *** Quercus robur *** Tilia cordata ** ** Ulmus sp. * * *** U. campestris * Viburnum opulus * II. Arctic-Alpine microthermal mesophyte species Betula nana ** * Dryas octopetala ** Gastrolychnis apetala ** Lycopodium pungens * Polygonum viviparum ** Potentilla cf. nivea ** Salix herbacea ** Salix cf. polaris ** Selaginella selaginoides ** * III. Herbaceous plants associated with various forest communities Botrychium ramosum * Humulus lupulus ** Lycopodium annotinum * L. clavatum *** * L. complanatum * L. selago * L. tristachyum * Thalictrum minus ** T. simplex *** Pteridium aquilinum *** * IV. Xerohalophytes Atriplex cana * A. pedunculata * A. verrucifera * Chenopodium glaucum ** * C. acuminatum * C. chenopodioides * Kochia prostrata *** Plantago cornuti * Salsola sp. * S. soda * V. Xerophytes Helianthenum sp. **** ** Eurotia ceratoides ******** Ephedra (non-distachya) ** * * Ephedra distachya ****** Kochia scoparia ***** VI. Psammophytes and plants growing on eroded soil Amaranthus sp. * Atriplex tatarica * Centaurea cyanus ** Chenopodium album *** C. botrys * Linaria sp. * Spergula sp. * (continued) Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 15

TABLE 3. THE LATE GLACIAL AND THE HOLOCENE PALEOFLORAS FOUND IN THE BLACK SEA DRAINAGE BASIN (continued)

Site names: Sloboda/ Yudinovo Seim Seim Svapa Seim Khoper Seim Svapa Svapa Svapa Svapa Drichaluki Numbers of fossil fl oras: Fl 1 Fl 2 Fl 3 Fl 4 Fl 5 Fl 6 Fl 7 Fl 8 Fl 9 Fl 10 Fl 11 Fl 12 Radiocarbon ages of the (17–18) (14–14.5) 13.8 12.6 12.4 12.2 11.9 11.5 (10.5) 9.8 7.5 4.9 fossil fl oras (k.y. B.P.)#: VII. Steppe and meadow plants Cannabis sp. * Fagopyrum sp. * Plantago ramosa * Rumex acetosella ** Botrychium lanceolatum * B. simplex * Bupleurum sp. * Papaver nudicaule ** Plantago lanceolata ** Sanguisorba offi cinalis ** * * * * Scabiosa sp. ** Thalictrum foetidum ** * Valeriana sp. ** VIII. Plants of wet meadows, water margins, and mires (helophytes) Alisma gramineum * A. plantago-aquatica * **** Calystegia sp. ** Equisetum palustre * E. scirpoides * E. variegatum ** Filipendula ulmaria ** Menyanthes trifoliata ** Myosoton aquaticum ** Polygonum amphybium * Ranunculus reptans ** Sparganium sp. ** * * * * * * S. hyperboreum ** Sagittaria sagittifolia **** Thalictrum angustifolium ** T. fl avum * Typha angustifolia * T. latifolia *** Urtica sp. ** IX. Aquatic plants Batrachium sp. ** Lemna sp. * Myriophyllum sp. * M. spicatum *** M. verticillatum ** * Nymphaea alba *** Nymphaea candida ** Potamogeton fi liformis ** P. natans * P. perfoliatus ** P. vaginatus ** #Age estimations based on interpolation are shown in parentheses. †Plants identifi ed by their pollen or spores. §Plants identifi ed by macrofossils.

others), Pteridium aquilinum, and other mesophile plants (see Sediments of the initial stage of fi lling of the large paleochan- Table 3). Such a fl oral composition suggests relatively humid nel of the Seim River (core S-4 in Fig. 3; 13,800 ± 85 yr B.P., conditions during the interval in question. A region analogue for Ki-6984) generally correspond to the beginning of the Oldest fossil fl ora 2 lies in the Altai Mountains, in the middle reaches of Dryas. Fossil fl ora 3, derived from these sediments, combines the Biya River, on the east-facing slopes (Fig. 6). In this region, cryophile (Alnaster fruticosus, Selaginella selaginoides) and pine and birch forests and spruce–fi r–Siberian pine mountain xerophile (Ephedra sp.) plants, inhabitants of the boreal forest, taiga forests occur along with wet meadows. The area is char- steppe, meadow, and riverine communities. The closest modern acterized by milder and wetter climatic conditions compared to fl oristic analogue for this assemblage can be found in the forest the region analogue 1: the mean January air temperature there is steppe in the middle reaches of the Irkut River basin, west of Lake –16 °C, and the mean July temperature is 16–17 °C. The mean Baikal (see Fig. 6). Within this small area, larch and pine forest annual precipitation is 700–800 mm, and the runoff depth is 500– grow next to southern Siberian meadow steppes, with patches of 550 mm (see Table 4). spruce forest in the river valleys. The area is characterized by a Downloaded from specialpapers.gsapubs.org on September 18, 2012

16 Sidorchuk et al. Figure 7. Estimations of the main climatic indexes (deviations from modern values) based on the composition of fossil fl oras (numbers of the fl oras are as in Tables 3 and 4 Fig. 6). Tables oras are as in oras (numbers of the fl based on the composition of fossil fl from modern values) (deviations Figure 7. Estimations of the main climatic indexes AL—Allerød; BØ—Bølling; DR1—Oldest Dryas. Dryas; PB—Preboreal; DR3—Younger Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 17

cold semiarid and extremely continental climate. The mean Janu- ary temperature is –24 °C, and that of July is ~16 °C. The mean 2.0

Runoff annual precipitation varies between 425 and 475 mm. The region depth ratio past/recent is situated near the boundary of the permafrost zone with a high annual runoff coeffi cient. The mean annual surface runoff depth is 350–400 mm (see Table 4). Another sample of fl uvial deposit fi ll from the large

(mm/yr) paleochannel of the Seim River was obtained from the basal part Runoff depth

Δ of core S-7 taken in the same profi le as core S-4 (Fig. 3). Accord- ing to the radiocarbon date (12,630 ± 70 yr B.P., Ki-6985), it corresponds to the fi nal part of the Oldest Dryas. The fl ora of this sample (fl ora 4 in Table 3) is distinctive for the diversity of

(mm/yr) its xerophytes and xerohalophytes, which suggest a rapid drying Runoff depth of the topsoil in the watershed areas during relatively warm sum- mers. Similar conditions occur at the present time in southern Siberia. A region analogue for fossil ﬂ ora 4 lies at the headwaters of the Yenisei River, within an intermountain depression down- (mm/yr)

Precipitation stream from the conﬂ uence of the Biy-Khem and Ka-Khem riv- Δ ers (Fig. 6). In this area, southern Siberian dry grassy steppes are found next to a mountain forest of Pinus sibirica and Larix sibirica. The area is characterized by extremely cold winters with mean January air temperature from –23 °C to –27 °C, while the (mm/yr)

Precipitation summer is warm with mean July temperature being ~18 °C. The annual magnitude of air temperature changes is ~43 °C, and that is ~15 °C greater than at the study site at the present time. The mean annual precipitation is ~400 mm, and calculated runoff July (°C) Temp. Δ depth is ~325 mm. Fluvial deposits ﬁ lling the paleochannel of the Svapa River were cored near Semenovka village (see Fig. 4). According to the 14C date (12,360 ± 110 yr B.P., Ki-6999), fossil ﬂ ora 5, deriving (°C) July

Temp. from core SV-1–8, belongs to the beginning of the Bølling inter- stadial. It includes species of dark coniferous taiga forest (Picea abies, Abies sibirica, Pinus sibirica), and light coniferous and mixed boreal forest (Pinus sylvestris, Pteridium aquilinum, Bet- (°C)

Temp. ula alba), along with species of riverine shrub associations, mead- Δ January ows, psammophytes (e.g., Spergula), and xerophytes. A region analogue for fossil ﬂ ora 5 lies at the headwaters of the Yenisei River. It is shifted to the north with respect to region analogue 4 (see Fig. 6). In this area, southern Siberian dry grassy steppes are (°C)

Temp. also the main vegetation type, though the role of the dark conifer- January –21 to –22 –13 to –14 8 to 10 –7 to –9 400 to 600 –200 to 0 350 to 500 140 to 290 ous mountain forest of Picea, Pinus sibirica, and Abies sibirica is slightly greater here compared to region analogue 4. The area is characterized by milder climatic conditions, with mean Janu- ary air temperature of –23 °C and mean July air temperature of Site names Sloboda/

Drichaluki ~17 °C, which are similar to the reconstruction based on fossil TABLE 4. MAIN CLIMATIC INDEXES IN THE BLACK SEA DRAINAGE BASIN LATE GLACIAL AND HOLOCENE fl ora 3. Therefore, the runoff coeffi cient could be the same as at the region analogue of fl ora 3. The mean annual precipitation is ~450 mm, and the calculated runoff depth is ~375 mm. Palynological data for the fl uvial deposits infi lling the (k.y. B.P.) ages of the fossil floras Radiocarbon paleochannel of the second generation in the Seim River valley were obtained from borehole S-11 (see Fig. 3). Flora 6, derived from a sample dated to 12,250 ± 70 yr B.P. (Ki-6987), includes 5 12.4 Svapa –21 to –25 –13 to –15 15 to 19 –4 to 0 425 to 475 –125 to –75 350 to 400 240 to 290 3.4 2 (14–14.5) Yudinovo 7 –14 to –18 –5.5 to –9.5 11.9 16 to 17 –1.5 to –2.5 700 to 800 Khoper 125 to 225 –16 to –18 500 to 550 –6 to –8 350 to 400 16 to 17 3.5 –3 to –4 500 to 600 40 to 140 150 to 200 40 to 90 1.6 4 12.6 Seim –23 to –27 –15 to –19 17 to 19 –2 to 0 375 to 425 –175 to –125 300 to 350 175 to 225 2.6 1 (17–18) 3 13.8 8 9 Seim 11.5 –22 to –26 (10.5) –14 to –18 Seim 15.5 to 16.5 Svapa –3.5 to –2.5 –15.5 to –16.5 425 to 475 –17 to –19 –7.5 to –8.5 17.5 to 18.5 –125 to –75 –0.5 to –1.5 –9 to –11 350 to 400 675 to 725 14.5 to 15.5 –3.5 to –4.5 125 to 175 225 to 275 400 to 500 –150 to –50 200 to 250 3.0 150 to 300 75 to 125 40 to 190 1.8 2.0 6 12.2 Seim –15.5 to –16.5 –7.5 to –8.5 16 to 18 –3 to –1 600 to 700 50 to 150 150 to 250 25 to 125 1.6 11 12 7.5 4.9 Svapa Svapa –15 to –16 –6 to –7 –7 to –8 18 to 19 1 to 2 0 to –1 18 to 19 650 to 700 0 to –1 100 to 150 625 to 675 130 to 180 75 to 125 20 to 70 65 to 125 1.4 –50 to 15 0.8 10 9.8 broad-leaved Svapa –15 to –16 –7 to –8 temperate 18.5 to 19.5 –0.5 to 0.5 500 to 600 tree –50 to 50 species 100 to 155 –10 to 45 (Quercus 1.2 , Ulmus, and Tilia fossil flora No. of cordata), as well as Alnus glutinosa, tree alder, growing on the Downloaded from specialpapers.gsapubs.org on September 18, 2012

18 Sidorchuk et al.

waterlogged ground. Its composition indicates that in the late of the Belaya River near the Southern Urals (Fig. 6). The region Bølling, the area was covered by a complex vegetation of forest is currently occupied by forest steppe, where meadow steppes steppe type, with birch and pine copses and minor participation are associated with birch and aspen woods and grow next to by broad-leaved trees. The presence of broad-leaved trees in the (1) larch-pine open forests with steppe elements in the herbaceous region implies a complete degradation of permafrost at the end of cover, and (2) broad-leaved (oak-linden) forests of Southern Ural the Bølling. This is confi rmed by the generally mesophile char- type. This area is characterized by the mildest climatic conditions acter of the fl ora and by the presence of pollen of relatively heat- for the entire Late Glacial, with mean January air temperature at demanding aquatic plants, such as Nymphaea alba (see Table –16 °C and July air temperature at 18 °C. Mean annual precipita- 3). A diversity of the hygro- and hydrophytes and an absence tion there reaches 700 mm, and runoff depth is ~225 mm, with of xerohalophytes in this fl ora suggest an increase in rainfall. A 60% of the fl ow passing during the spring fl ood. Annual runoff region analogue for fossil fl ora 6 lies at the headwaters of the Ufa coeffi cient is 0.32, and that for the fl ood period is ~0.56. River in the Southern Ural Mountains (Fig. 6). In this region, Fossil fl ora 9 is derived from a loam and clay sediment layer meadow steppes come into close contact with the southern in core SV-1–8, which is correlated with the Younger Dryas on the Urals pine and birch forests and spruce-fi r subtaiga forests, with basis of pollen composition and radiocarbon dating. This horizon a minor presence of broad-leaved trees. The area is character- is distinguished by high nonarboreal pollen content, as well as a ized by signifi cantly milder climatic conditions compared to the distinct maximum of Artemisia pollen and a smaller peak of Che- region analogue of the early Bølling fl ora 5: the mean January nopodiaceae. Among trees, Pinus sylvestris and Betula alba were air temperature there is –16 °C, and the mean July temperature predominant. Of the dark coniferous trees, Picea abies and Pinus is ~17 °C. The mean annual precipitation is 650 mm, and the sibirica are registered in this fl ora. Of the cold-tolerant shrubs, runoff depth is ~200 mm, with 70% of the fl ow passing during Betula humilis and Alnaster are present. Relatively thermophilic the spring fl ood. The annual runoff coeffi cient is 0.31, and that trees once again disappear from the local fl ora (see Table 3). for the fl ood period is ~0.6. Changes in the fl ora are indicative of both colder and more arid The alluvium deposits infi lling the meandering Khoper climatic conditions compared to the previous time interval, with paleochannel were studied near the town of Povorino (see Fig. probable reestablishment of permafrost in the region. A region 5). At the base of core B, a radiocarbon date was obtained for analogue for fossil fl ora 9 is situated in the middle reaches of the layer enriched with organic matter: 11,900 ± 120 yr B.P. the Biya River in the Altai Mountains (Fig. 6). In the vegetation (Ki-5305). The fl ora of this horizon includes some arboreal spe- cover of this area, open larch woodlands with steppe elements cies with broad ecological tolerances, such as Scots pine (Pinus and patches of steppes are distributed next to fi r and Siberian pine sylvestris) and tree and shrub birch (Betula alba, Betula humi- forests on the mountain slopes. Birch and Scots pine commu- lis), but it also includes Siberian pine (P. sibirica), growing in the nities occur on sandy soil. The area is characterized by a cold, regions with continental climate, xerohalophytes, and xerophytes continental, and relatively dry climate with mean annual precipi- (Atriplex pedunculata, Atriplex verrucifera, and others; see Table tation of 450 mm and runoff depth of 150–300 mm. The mean 3). A region analogue of fossil fl ora 7 is located in northeastern January air temperature is –18 °C, and that of July is 15 °C. Kazakhstan, in the Bukhtarma River basin (Irtysh River basin) at Floras 10–12, deriving from palynological data of peat in the boundary between dry steppe and semidesert and close to the core SV-1–8 from the Svapa River valley, indicate a conspicu- region where communities of shrub birch and open dark coniferous change of landscape and climatic conditions at the transition ous forest are spread on the western slopes of the Altai Moun- from the Late Glacial to the Holocene. These fl oras are domi- tains (Fig. 6). The mean January air temperature in this region is nated by forest and meadow plants (see Table 3). Their closest –17 °C; mean July temperature is ~16.5 °C. The mean annual present-day analogues are located within the boreal forest zone precipitation varies between 500 and 600 mm. The annual runoff and, for the Atlantic period of the Holocene, broad-leaved forest depth is 150–200 mm. The region analogue is situated beyond zone near the boundary of the steppe zone (see Fig. 6). These the permafrost zone but close to its boundary. changes suggest a considerable rise in temperature and precipi- Fossil fl ora 8 of the dated sample from section S-11 (see Fig. 3; tation, decrease in the runoff coeffi cient because of degradation 11,450 ± 60 yr B.P., Ki-6986) includes many helophytes—plants of permafrost, and, therefore, a substantial decrease in surface growing on wet meadows, near the water’s margin, and in shallow runoff (see Table 4). water (Sparganium spp., Menyanthes trifoliata, Sagittaria sagit- On the whole, changes in geographical position and hydro- tifolia, and others; see Table 3). Composition of this fl ora indicates climatic characteristics of the paleofl oristic region analogues that the Allerød warm interval was favorable for the expansion refl ect a complexity of climate change during the Late Glacial of dark coniferous trees (Picea abies, Pinus sibirica, and Abies) against the background tendency toward warmer and wetter in the Seim River basin. Forest communities were dominated by climate (see Fig. 7). Secondary oscillations can be seen on this birch and Scots pine, and larch participated in the pine forest at general trend. Air temperature was the lowest in the LGM, in this period. Of the relatively thermophile trees and shrubs, fl ora the late part of the Oldest Dryas, and in the Younger Dryas. Rela- of the Allerød included Ulmus, Tilia, Corylus, and Viburnum. A tively warm intervals precede the Oldest Dryas and correspond to modern analogue for fossil fl ora 8 is located at the headwaters the Bølling and the Allerød. Extremely low winter temperatures Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 19

indicate the existence of permafrost during the Late Pleniglacial, was assumed to be constant and equal to 60 mm yr–1, according the Oldest Dryas to early Bølling, and in the Younger Dryas. to measurements on recent glaciers. The results are more qualita- Precipitation changes in the LGM and LGT generally fol- tive than quantitative because of the great uncertainty about the lowed temperature changes, the cold stages being relatively structure and coeffi cients of Equations 1–8. Nevertheless, these dry, and the warm stages relatively humid, with the maxi- estimates show a very large meltwater supply to the headwaters mum precipitation achieved in the pre–Oldest Dryas warming of the Dnieper River and its tributaries (Berezina and Pripyat Riv- (ca. 14.5–14 14C k.y. B.P.), and in the Bølling-Allerød interst- ers), which at the early stages of deglaciation was comparable with ade (ca. 12.5–11 14C k.y. B.P.). Surface runoff is not determined recent annual surface runoff from the Dnieper River basin: 54 km3. entirely by annual precipitation, since water losses depend on air The sizes of the blow-out channels coeval with this large temperature. The runoff coeffi cient is inversely correlated with meltwater supply (see Fig. 2) yield an additional possibility for temperature changes, showing a strong overall decrease during estimating its volume. Using Equation 9 along with the width the LGM-LGT. Generally following changes in runoff coeffi - W and meander half-wavelength λ of these paleochannels (Table cient, the surface runoff also decreased considerably during this 5), the mean annual discharge Q and annual yield V were esti- period (Fig. 7). Secondary oscillations of precipitation and water mated. Presumably, the seasonality of runoff was high, so index losses led to signifi cant variations in surface runoff. The great- of runoff variability y = 5. Paleochannel effective width W* was est runoff was characteristic of the pre–Oldest Dryas warming, calculated as because of relatively high precipitation, low losses, and preserved W + (λ/ k ) permafrost. The second highest runoff maximum was achieved W* = λ . (12) at the beginning of the Bølling interval, when the temperatures 2 still remained low while precipitation began to rise. During the λ cold and dry Younger Dryas, an increase in runoff was caused by Here, kλ is /W; the mean value of the ratio is equal to 5.6 for low water losses to evaporation. During the warm and relatively the paleochannels in the plains of northern Eurasia (Sidorchuk et humid Bølling and Allerød interstadials, higher losses to evapo- al., 2008). ration caused a relative decrease in surface runoff. Nevertheless, This estimate of annual meltwater supply (from 60 km3 the entire LGM-LGT interval was characterized by high surface annually) is close to the “dead-ice” scenario and in general con- runoff compared to the present-day level, which was achieved at fi rms a very large volume of meltwater fl owing to the Black Sea the beginning of the Holocene (see Fig. 7). basin in the early stages of the ice-sheet retreat.

Estimation of the Meltwater Supply in the Dnieper River Estimation of Surface Runoff in the Dnieper and Don River Basin during the Early Stages of the Ice-Sheet Retreat Basins during the Period of Large Paleochannel Formation

Morphometrical parameters of the Fennoscandian ice sheet Calculations with Equations 9–11 require knowledge of at the LGM (Bologoye)–Vepsovo stages (see Fig. 2) along with paleochannel morphology and a modern hydrological analogue Equations 1–8 provide an estimate of change in glacier volume, of the ancient river. Paleochannel effective width W* was esti- snow accumulation, and fi nal mass budget (Table 1). Such estimated with Equation 12 with the mean relative error of 15% (see mates were made for three main scenarios: a “cold” glacier with Table 2). The climatic region analogues for Late Glacial time a shape similar to those of the Antarctic and Greenland glaciers; were estimated from paleofl oristic analysis (see Fig. 6). For rela- a “warm” glacier with a fl atter hypothetical shape, derived from tively mild periods of the Late Glacial (pre–Oldest Dryas warm- some assumptions about Fennoscandian glacier dynamics (Kho- ing, Bølling and Allerød interstadials), analogues are situated dakov 1982); and a “dead-ice” glacier with a marginal zone of in the basins of the Biya River (the Altai Mountains) and of the “inactive” ice with 500 m thickness, which follows from geomor- Belaya River (southeastern Ural Mountains). For the cold peri- phologic considerations (Chebotareva and Faustova, 1982; Faus- ods (the LGM, the Oldest, Older, and Younger Dryas), the mod- tova, 1984). Mean annual evaporation from the glacier surface ern region analogues are located in the southeastern sub-Baikal

TABLE 5. MELTWATER FLOW THROUGH THE MAIN PALEOCHANNELS FROM THE ICE-DAM LAKES IN THE UPPER DNIEPER RIVER BASIN Meander Channel Effective Mean annual Annual water λ Paleochannel half-wavelength, width, W width, W* discharge, Qa yield volume, V (m) (m) (m) (m3/s) (km3) Paleochannel from the Upper Neman ice-dam lake to the Pripyat' River through the Schara River 5250 1600 1270 650 20 Paleo–Berezina River near Borisov 3540 1200 920 400 13 Paleo–Dnieper River near Rogachev 8600 1800 1670 950 30 Downloaded from specialpapers.gsapubs.org on September 18, 2012

20 Sidorchuk et al.

region and at the headwaters of the Yenisei River (the Sayan was estimated with Equation 10, using y and Qa. Surface runoff Mountains). These territories can be used as hydrological ana- depth X (mm yr–1) from basin area F (km2) was calculated as logues only partly (for example, for the estimation of runoff coef- Q fi cient) because of the mountainous relief, high inclinations, and X = 536,31 a . (13) small areas of the river basins. For the estimation of such charac- F teristics as discharge variability, lowland territories with similar climatic indexes (mean temperature of January and July, annual The structure of Equation 9 leads to an increase in the rela- precipitation) and landscapes, close to those of the LGT (sparse tive error of discharge estimation compared to the relative error open vegetation, widespread permafrost), must be selected. The of channel width estimation. Therefore, the errors of paleodis- lowland with climatic characteristics similar to those in the Altai charge and runoff depth estimates for the Dnieper and Don River and Ural Mountains, is the Bol’shezemel’skaya Tundra in the basins are close to ±20%. northeastern part of European Russia. The lowland with climatic Although we obtained only a few 14C dates from paleochan- characteristics similar to the Yenisei River headwaters is located nel deposits in the Dnieper and Don River basins (see descriptions within the Lena Plateau in central Yakutia (see Fig. 6). Hydrolog- of the key sites), these dates support a hypothesis of synchronous ical regimes of large rivers in these two territories are quite simi- activity of the large rivers. As the oldest large paleochannels were lar: spring fl ood is high and sharp, and most of the annual fl ow abandoned 15–13 14C k.y. B.P., the large rivers were active in passes during the fl ood. Low water period during the summer, pre–Oldest Dryas time. Therefore, information from Table 2 can autumn, and winter is long, but some years only 10%–12% of the be used to reconstruct the spatial distribution of surface runoff annual runoff passes during this period. Coeffi cient a in Equation within the Dnieper and Don River basins for this period (Fig. 8), 11, which depends on hydrological regime, is therefore very sim- and to estimate the volume of water fl owing into the Black Sea ilar for these two territories: it is 2.25 for the Bol’shezemel’skaya from these basins. Tundra and 2.23 for the Lena Plateau. The general pattern of the pre–Oldest Dryas runoff is quite The sequence of paleohydrological calculations is as fol- similar to the modern longitudinal decrease in runoff depth from lows. The coeffi cient of within-year fl ow variability y for the past north to south in the Dnieper and Don River basins (Figs. 8A and hydrological regime was estimated with Equation 11 for each 8B). Maximum runoff was reconstructed for the area adjacent to river basin in Table 2, using coeffi cient a = 2.25. Basin area was the ice sheet, though none of the rivers used in the calculations assumed to be constant since the LGT. The mean annual paleo- was fed by glacier meltwater in the pre–Oldest Dryas. There 3 –1 discharge Qa m s was calculated with Equation 9, using y and was some lateral differentiation in the runoff: the Dnieper River

effective width W*. The mean maximum paleodischarge Qmax basin was drier than the Don River basin. The same effect can be

Figure 8. Surface runoff in the East European part of the Black Sea drainage basin: (A) recent (measured) (after Evstigneev, 1990); and (B) calculated for the period of activity of large meandering rivers (pre–Oldest Dryas time). Key: (1) annual depth of surface runoff (mm); (2) data sites. Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 21

TABLE 6. VOLUME OF ANNUAL SURFACE RUNOFF FROM THE DNIEPER AND DON RIVER BASINS tneceR etaL laicalginelP

River Basin area Annual runoff volume, VR Basin area Annual runoff volume, VP VP/VR (km2) (km3) (km2) (km3) Don 422,000 29 422,000 110 3.8 Dnieper 504,000 54 504,000 166 3.1 Total 926,000 83 926,000 276 3.3

distinguished in the recent runoff pattern (Fig. 8A). The runoff that the meltwater supply was at least equal to recent runoff from during the pre–Oldest Dryas warming was much greater than the the Dnieper River basin, and possibly in excess. This estimate is modern value. Runoff depth reached 600 mm in the basins of confi rmed by the morphology of the blow-out channels, through the Upper Dnieper and Don. It was also ~600 mm in the west- which the meltwater passed. ern part of the Dnieper River basin. In the eastern part of the Paleoclimatic reconstructions for the LGM are based on data Dnieper River basin, runoff depth decreased rapidly in the north- from the Drichaluki site, which characterize the Upper Dnieper south direction. It was ~400–600 mm at the headwaters and did basin. They reveal a cold and relatively dry environment with not exceed 100–200 mm in the middle and lower Dnieper River precipitation lower than at present (see Table 4). Low winter and basin. Runoff was more than 200 mm in the upper and middle summer air temperatures and the existence of deep permafrost Don River basin, and only at the lower reaches did it decrease led to low precipitation losses from infi ltration and evaporation. to 100 mm. The excess of annual water fl ow above the modern Therefore, surface runoff was higher than recently, in spite of the value can be explained by greater precipitation and lower losses lower precipitation. During the Late Pleniglacial, landscape and (greater runoff coeffi cient values). climatic conditions over the Russian Plain were less differentiated The rate of north-to-south decrease in runoff was lower in the than at present, and the so-called periglacial hyperzone was formed past than at present. In the Dnieper River basin, the modern ratio (Velichko, 1973). At the LGM, permafrost in the Russian Plain between the runoff depth at the headwaters (200 mm) and lower reached 45°N (Velichko et al., 1982), thus including the major part reaches (20 mm) is 10; during the pre–Oldest Dryas warming, of the Dnieper River basin. Taking this into consideration, annual it was 6 (600 mm/100 mm). In the Don River basin, these ratios meteoritic water runoff from the Dnieper basin on the whole was are closer to one another (150 mm/20 mm and 600 mm/100 mm) estimated at 100 km3, which is about two times greater than recent because of a smaller north-south extent of the basin. totals. With the additional 60 km3 of meltwater runoff, the cumula- The map in Figure 8B allows one to calculate an annual vol- tive runoff to the Black Sea from the Dnieper River basin at the ume of surface runoff for the period of large river activity and to LGM was signifi cantly larger than recent runoff from the entire compare it with recent characteristics (Table 6). During the pre– East European part of the Black Sea drainage basin. Oldest Dryas warming, the Don River supplied about four times Extraordinary morphological features—large meandering the present-day water volume, and the Dnieper River supplied paleochannels—mark the next hydrological period at the end about three times the volume. If we apply these proportions to other rivers, the total annual surface runoff from the East Euro- pean part of the Black Sea basin can be estimated at ~365 km3. Even if we keep recent values for the runoff from region III, the estimate will be more than 300 km3, i.e., almost three times greater than the modern runoff from this area and even greater than the modern runoff from the entire Black Sea drainage basin.

DISCUSSION

Morphological, geological, geochronological, and palynological information on the East European part of the Black Sea drainage basin enables a reconstruction of the landscape, climate, and hydrological history of this region (Fig. 9). The amount of available paleogeographical data on different time intervals varies, inﬂ uencing the reliability of the suggested interpretations. The weakest evidence is related to the hydrological regi- men at the LGM. The great uncertainty in the paleoglaciologi- Figure 9. Reconstructed surface runoff in the East European part of the cal reconstruction of the shape and budget of the Fennoscandian Black Sea drainage basin during the Last Glacial Maximum (LGM) ice sheet makes the estimate of meltwater supply to the Dnieper and Late Glacial time (LGT). PB—Preboreal; DR3—Younger Dryas; River basin more qualitative than quantitative. It is possible to say AL—Allerød; BØ—Bølling; DR1—Oldest Dryas. Downloaded from specialpapers.gsapubs.org on September 18, 2012

22 Sidorchuk et al. of the Pleniglacial (pre–Oldest Dryas warming). Existing dates the short period when glaciers retreated very rapidly between ca. (see Table 1 in Sidorchuk et al., 2008) show that this period had 17 and ca. 16.5 14C k.y. B.P., and afterward, it gradually decreased begun before 15 ka (the Moskva River paleochannel). In the until the beginning of the Holocene. Dnieper and Don River basins, widths and meander wavelengths The morphology and deposits of the large paleorivers were of the large paleochannels are ten to fi fteen times greater than investigated by Borsy and Felegyhazi (1983), by Kasse et al. (2000) those of the modern channels with the same drainage areas. The in Hungary, and by Howard et al. (2004) in Romania. These investi- closest modern hydrological analogue for this period is an open gations showed that large rivers in the Tisza River basin were active tundra landscape with permafrost and long, severe winters with at the end of the Pleniglacial, i.e., at the beginning of the LGT (Dr. considerable snowfall (see Fig. 6). In such landscapes, short and K. Kasse, 2008, personal commun.). Large rivers in Romania were high spring fl oods with large discharges formed large meander- active before 12 14C k.y. B.P. (Howard et al., 2004). These estimates ing channels. During the rest of the year, these channels were correspond in general to the dates obtained in the East European nearly empty. Using the large paleochannel morphology, we can Plain (Sidorchuk et al., 2008). The widths and meander lengths roughly calculate the annual surface runoff from the East Euro- of radiocarbon-dated large paleochannels were measured on pean part of the Black Sea basin during the pre–Oldest Dryas Landsat-7 images. Calculations using Equations 9–11 show that, warming at ~300–365 km3. during the LGT, the Carpathian tributaries of the Danube supplied Because of low differentiation of landscapes within the peri- three times their present-day discharge. Presumably, the runoff glacial hyperzone, we can assume that past/recent runoff ratios, from the Danube River basin changed in similar ways to that in estimated in the region analogues, can be extended to the whole the East European part of the Black Sea basin (see Fig. 9), with its East European part of the Black Sea basin. This assumption is sup- maximum shifted toward the beginning of the LGT. ported by the results of our reconstructions. Thus, in the region The history of the last connection between the Black Sea and analogue located for fossil fl ora 2 (see Fig. 6), the ratio between the Caspian Sea through the Manych Strait has been analyzed by the past and recent runoffs is equal to 3.5 (see Table 4). A very many researchers (e.g., Goretskiy, 1957; Popov, 1983; Menabde similar ratio (3.2) was reconstructed for the Late Pleniglacial in the and Svitoch, 1990), but still many questions remain unsolved, Moskva River basin near Moscow (Sidorchuk et al., 2009). There- mostly regarding the chronology of events and the water budget. fore, using the reconstructed values of the main hydroclimatic This connection occurred at some time during the early phase of indexes for various intervals of the LGT (see Table 4), we calcu- the Khvalynian transgression of the Caspian Sea, which is dated lated water discharge from the East European part of the Black to 20–7 14C k.y. B.P. (Svitoch, 1991). The maximum level of the Sea drainage (Fig. 9). Following the maximum reached at the end fi rst stage of this transgression was about +50 m asl or +78 m of the Pleniglacial, the discharge generally decreased, although it above the recent level of the Caspian Sea. This stage is marked remained greater than the modern value until the beginning of the by +50 m marine terraces with the deposits containing the Khval- Holocene. The decrease in water discharge was interrupted by two ynian malacofauna, and by the river terraces of the tributaries of events of high runoff. A secondary system of large paleochannels the Lower Volga River. Alluvium that built up these terraces cor- in the Khoper River basin (see Fig. 5) was formed during the sec- responds to marine and estuarine deposits of the transgression ond of these events, which corresponds to the Younger Dryas. (Obedientova, 1977). The remnants of the large paleochannels on The East European part of the Black Sea basin makes up these river terraces (Sidorchuk et al., 2009) show that their for- about one third of its recent basin. Of the rest of the Black Sea mation took place within the stage of large river activity at the basin, the Danube River basin is the largest part. When the Cas- LGT, which corresponds to the latest radiocarbon dates associated pian Sea was connected to the Black Sea through the Manych with the maximum phase of the Khvalynian transgression: 14– Strait, the Black Sea drainage basin increased dramatically. Next, 11 ka (Svitoch and Yanina, 1997), 16–11 ka (Leonov et al., 2002), we shall discuss briefl y the water supply from the Danube River 16–13 ka (Chepalyga et al., 2008). Our calculations for that stage and from the Caspian Sea during the LGM and LGT. of the Caspian Sea water budget (Panin et al., 2005; Sidorchuk The Danube River basin can be divided into two main mor- et al., 2009) show that runoff from the large rivers in the Volga phological regions: (1) the Alpine and subalpine region of glacial River basin (~500 km3 yr–1) was suffi cient to build up the highest morphology, which can be used for paleoglaciological reconstruc- level of the Khvalynian transgression. However, this runoff was tion, and (2) the sub-Carpathian region, which shows clear traces not large enough to maintain the long-term fl ow of Caspian water of large river activity. Within the latter, the morphology of the large into the Black Sea through the Manych Strait. The mean sizes paleochannels can be used for paleohydrological reconstructions. of fl uvial features in the Manych Straight (channel width ~8 km, The Last Glaciation in the eastern Alps, where most of the length of alternating bars ~20 km, height 15–20 m, and meander Danube tributaries have their origin, was described in detail by half-wavelength ~40 km) support the hypothesis of a very high van Huzen (2004). Application of Equations 1–8 to van Huzen’s discharge during their formation. The mean annual discharge of estimates of the position and age of various stages of the Last ~65,000 m3 s–1 calculated for a stream with such geometry using Glaciation gives the following results: during the period between Equation 9 and y = 100 (stable runoff from a large lake, when 14 ca. 21 and ca. 17 C k.y. B.P., meltwater supply to the Upper Qmax is close to Qa) is greater than the fl ood discharge at the Lower Danube was very low; it was much higher (~35 km3 yr–1) during Mississippi River. Annual volume of runoff through the Manych Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 23

Strait was ~2000 km3 yr–1. Note, that Chepalyga (2007) used a 1. A cold and dry interval with precipitation lower than today different method of discharge estimation: the product of channel and a high runoff coeffi cient caused by low evaporation losses cross-section area and fl ow velocity. For the Zunda-Tolga profi le, and continuous spread of permafrost correlates with the LGM cored by Popov (1983), the cross-section area was estimated as and the beginning of deglaciation, 18–15 14C k.y. B.P. A rela- 250,000 m2 (width of 10,000 m on a mean depth of 25 m). Flow tively high surface runoff (210 km3 yr–1) caused by precipitation velocity was estimated at 0.2 m s–1 according to sediment particle was then supplemented by meltwater infl ux (60 km3 yr–1) from size. Calculated discharge (Chepalyga, 2007) was 50,000 m3 s–1. proglacial lakes. That is rather close to our estimate, taking into account the com- 2. A warmer, humid interval with precipitation exceeding pletely different approach to fi guring the result. that of today and a high runoff coeffi cient caused by relatively The most probable hypothesis that can explain these facts low temperatures correlates with the pre–Oldest Dryas time, is that a high threshold with its top at about +50 m asl existed 15–14 14C k.y. B.P. This was a period of very high surface runoff in the middle of the Manych Strait. This natural dam separated (300–365 km3 yr–1), when large meandering river channels were the high-standing Caspian Sea from the relatively low-standing formed. A short event occurred within this period when a large Black Sea (Menabde and Svitoch, 1990). At some moment, the amount of Caspian water (23,000 km3) was supplied to the Black dam was eroded to a level of about +22 m asl. As a result, the Cas- Sea through the Manych Strait. pian Sea water from between +50 and +22 m asl (~23,000 km3) 3. An interval with short-term climatic oscillations and non- was emptied into the Black Sea during a period of only 20–30 yr. steady decrease of surface runoff, from ca. 14 to 10 14C k.y. B.P., This event happened within the large river stage. This assumption corresponds to the LGT. Secondary climatic oscillations during is supported by the existence of remnants of large paleochannels the LGT were expressed against the overall trend toward warm- on the terraces of the tributaries of the Volga River, which were ing, primarily the rise of winter temperatures. Phases with the formed both before and after incision of those tributaries due to lowest air temperatures (the Oldest and Younger Dryas) were the Caspian Sea level drop (Sidorchuk et al., 2009). Some radio- favorable for permafrost development and to low losses, provid- carbon dates indicate that the fl ow via the Manych Strait took ing high runoff coeffi cients and, therefore, increasing the runoff place between the beginning of the late Valdai/late Weichselian (up to 355 km3 yr–1) despite a decrease in precipitation. Phases deglaciation and 12 ka (Arslanov and Yanina, 2008). with relatively high air temperatures (Bølling and Allerød intersta- Our reconstruction of high river runoff into the Black Sea at dials) were favorable for permafrost degradation and higher losses the LGM and LGT (2–2.5 times greater than the present; see Fig. to evapotranspiration, providing low runoff coeffi cients and there- 9) does not support the “fl ood hypothesis” proposed by Ryan et fore decreasing the runoff (to 165 km3 yr–1) despite an increase in al. (1997). This hypothesis holds that the –120 to –150 m stage precipitation. By the end of this time interval, large meandering of the Black Sea lasted until ca. 7 14C k.y. B.P. The estimated paleochannels were transformed into smaller channels. high river runoff does not agree with a low level and isolated-lake The entire LGM-LGT interval was characterized by high status of the Black Sea throughout the LGM and LGT. Today, surface runoff from the East European part of the Black Sea the Black Sea has a positive water balance with some 300 km3 drainage basin compared to that of the present day (110 km3 yr–1), of excess water removed annually via the Bosphorus (Özsoy et which was achieved at the beginning of the Holocene. al., 1995). To maintain a low stage at the LGM and LGT, the values of effective evaporation should have been much higher ACKNOWLEDGMENTS than today. Reconstructions of Tarasov et al. (1999) for the LGM provide quite the opposite result, suggesting a rate of evaporation Financial support for this work was received from the Russian that was lower than present. Low evaporation aided by high water Foundation of Basic Research (RFBR), project no. 97-05-64708, supply from the drainage basin make it more probable that the 00-05-64021, and 09-05-00340. Valuable suggestions by review- Black Sea was fi lled up to the Bosphorus sill (now ~35 m below ers J. Herget and T. Kalicki were incorporated into the text. sea level) in the LGT, with large amounts of excess freshwater fl owing via this channel straight into the Marmara Sea. This is REFERENCES CITED supported by recent fi ndings of Giosan et al. (2009) that the sub- aerial deltaic plain of the Danube River, which is indicative of Aksu, A.E., Hiscott, R.N., Yaşar, D., Işler, F.I., and Marsh, S., 2002, Seismic the sea-level position, was located around 30 m below sea level stratigraphy of late Quaternary deposits from the southwestern Black Sea shelf: Evidence for non-catastrophic variations in sea-level during the directly before the Black Sea to world ocean reconnection was last ~10,000 yr: Marine Geology, v. 190, p. 61–94, doi: 10.1016/S0025 established at ca. 8.4 ka. -3227(02)00343-2. Arslanov, Kh., and Yanina, T., 2008, Radiocarbon age of the Khvalynian Manych passage, in Gilbert, A.S., and Yanko-Hombach, V., eds., Extended CONCLUSIONS Abstracts of the Fourth Plenary Meeting and Field Trip of IGCP 521 “Black Sea–Mediterranean Corridor during the Last 30 k.y.: Sea Level Three time intervals can be distinguished within the general Change and Human Adaptation,” and INQUA 0501 “Caspian–Black Sea– Mediterranean Corridor during the Last 30 k.y.: Sea Level Change and sequence of hydrological events in the East European part of the Human Adaptive Strategies” (4–16 October 2008; Bucharest, Romania, Black Sea drainage basin during the LGM and LGT. and Varna, Bulgaria): Bucharest, GeoEcoMar, p. 15–18. Downloaded from specialpapers.gsapubs.org on September 18, 2012

24 Sidorchuk et al.

Bahr, A., Arz, H.W., Lamy, F., and Wefer, G., 2006, Late Glacial to Holocene Giosan, L., Filip, F., and Constatinescu, S., 2009, Was the Black Sea catastroph- paleoenvironmental evolution of the Black Sea, reconstructed with stable ically fl ooded in the early Holocene?: Quaternary Science Reviews, v. 28, oxygen isotope records obtained on ostracod shells: Earth and Planetary p. 1–6, doi: 10.1016/j.quascirev.2008.10.012. Science Letters, v. 241, p. 863–875, doi: 10.1016/j.epsl.2005.10.036. Goretskiy, G.I., 1957, O sootnoshenii morskikh i kontinental’nykh osadkov Pri- Borisova, O.K., and Novenko, E.Yu., 1999, Sreda obitaniya pozdnepal- azoviya, Primanychya i Nizhnego Pridonya [On the correlation of marine eoliticheskogo cheloveka na stoyanke Yudinovo (po palinologicheskim and continental deposits in the Azov, Manych and lower Don basins]: dannym) [Environmental conditions at the Late Paleolithic site Yudinovo Trudy Komissii po Izucheniyu Chetvertichnogo Perioda [Proceedings of (based on palynological data)], in Bolikhovskaya, N.S., and Rovnina, the Commission on Quaternary Studies], v. 13, p. 36–54 (in Russian). L.V., eds., Aktual’nye problemy palinologii na rubezhe tret’ego tysyache- Grichuk, V.P., 1969, Glyatsial’nye fl ory i ikh klassifi katsiya [Glacial fl oras and letiya [Topical Problems in Palynology at the Beginning of the Third Mil- their classifi cation], in Gerasimov, I.P., ed., Posledniy lednikovyi pokrov lennium]: Moscow, IGIRGI Press, p. 54–60 (in Russian). na severo-zapade Evropeiskoi chasti SSSR [The Last Ice Sheet in the Borisova, O.K., Sidorchuk, A.Yu., and Panin, A.V., 2006, Palaeohydrology of Northwestern European Part of the USSR]: Moscow, Nauka, p. 57–70 the Seim River basin, Mid-Russian Upland, based on palaeochannel mor- (in Russian). phology and palynological data: Catena, v. 66, p. 53–73, doi: 10.1016/ Grichuk, V.P., 1982, Rastitel’nost’ Evropy v pozdnem pleistotsene [Vegetation j.catena.2005.07.010. of Europe during the late Pleistocene], in Gerasimov, I.P., and Velichko, Borsy, Z., and Felegyhazi, E., 1983, Evolution of the network of water courses A.A., eds., Paleogeografi ya Evropy za poslednie sto tysyach let (Atlas- in the north-eastern part of the Great Hungarian Plain from the end of the monografi ya) [Palaeogeography of Europe during the Last 100,000 Years Pleistocene to our days: Quaternary Studies in Poland, v. 4, p. 115–124. (Atlas-Monograph)]: Moscow, Nauka, p. 92–109 (in Russian). Chebotareva, N.S., and Faustova, M.A., 1982, Struktura i dinamika posled- Hintikka, V., 1963, Über das Großklima einiger Pfl anzenareale in zwei Klima- nego Evropeiskogo lednikovogo pokrova [Structure and dynamics of the koordinatensystemen dargestellt: Annales Botanici Societatis Zoologicae, last European ice-sheet], in Gerasimov, I.P., and Velichko, A.A., eds., Botanicae Fennicae ‘Vanamo,’ v. 34, p. 1–64. Paleogeografi ya Evropy za poslednie sto tysyach let (Atlas-monografi ya) Howard, A.J., Macklin, M.G., Bailey, D.W., Mills, S., and Andreescu, R., 2004, [Palaeogeography of Europe during the Last 100,000 Years (Atlas- Late-Glacial and Holocene river development in the Teleorman Valley on Monograph)]: Moscow, Nauka, p. 36–48 (in Russian). the southern Romanian Plain: Journal of Quaternary Science, v. 19, no. 3, Chebotareva, N.S., and Makarycheva, I.A., 1974, Poslednee oledenenie Evropy p. 271–280, doi: 10.1002/jqs.805. i ego geokhronologiya [Last Glaciation in Europe and Its Geochronol- Iversen, J., 1944, Viscum, Hedera, and Ilex as climate indicators. A contribution ogy]: Moscow, Nauka, 216 p. (in Russian). to the study of the post-glacial temperature climate: Geologiske Föreni- Chepalyga, A.L., 2007, The Late Glacial Great Flood in the Ponto-Caspian gens i Stockholm Förhandlingan, v. 66, p. 463–483. basin, in Yanko-Hombach, V., Gilbert, A.S., Panin, N., and Dolukhanov, Kalicki, T., 1995, Late Glacial and Holocene evolution of some river valleys in P.M., eds., The Black Sea Flood Question: Changes in Coastline, Climate, Byelorussia: Paläoklimaforschung, v. 14, p. 89–100. and Human Settlement: Dordrecht, Springer, p. 119–148. Kalicki, T., and San’ko, A., 1992, Genesis and age of the terraces of the Dnieper Chepalyga, A.L., Arslanov, Kh., and Svetlitskaya, T., 2008, Chronology of the River between Orsha and Shklow, Byelorussia: Geographia Polonica, Khvalynian sea-level oscillations: New data and approach, in Gilbert, v. 60, p. 151–174. A.S., and Yanko-Hombach, V., eds., Extended Abstracts of the Fourth Kalinin, G.P., Markov, K.K., and Suetova, I.A., 1966, Kolebaniya urovnya Plenary Meeting and Field Trip of IGCP 521 “Black Sea–Mediterranean vodoemov Zemli v nedavnem geologicheskom proshlom: Okeanologiya Corridor during the Last 30 k.y.: Sea Level Change and Human Adap- [Oceanology], v. 6, p. 737–746. tation,” and INQUA 0501 “Caspian–Black Sea–Mediterranean Corridor Kapitsa, A.P., 1958, O zavisimosti formy lednikovogo kupola Vostochnoi Antarktidy during the Last 30 k.y.: Sea Level Change and Human Adaptive Strat- ot reliefa podlednogo lozha i kharaktera rastekaniya l’da [On the dependence egies” (4–16 October 2008; Bucharest, Romania, and Varna, Bulgaria): of the East Antarctic ice-sheet shape on the underlying topography and ice Bucharest, GeoEcoMar, p. 32–34. rheology]: Informatsionnyi Bulleten’ Sovetskoi Antarkticheskoi Ekspeditsii Dolukhanov, P.M., Chepalyga, A.L., Lavrentiev, N.V., Kadurin, S.V., Larchen- [Information Bulletin of the Soviet Antarctic Expedition], v. 1, p. 1–17. kov, E.P., and Shkatova, V.K., 2008, Black Sea and Caspian Basins in late Kasse, C., Vandenberghe, J., Beets, C., and Van Huissteden, J., 2000, Changing Pleistocene: sea-level changes, climate and early human settlement, in Gil- fl uvial styles during the last glacial-interglacial transition in the Tisza val- bert, A.S., and Yanko-Hombach, V., eds., Extended Abstracts of the Fourth ley, Hungary, in Georgiadi, A., ed., Conference Papers and Abstracts Pro- Plenary Meeting and Field Trip of IGCP 521 “Black Sea–Mediterranean ceedings of the Fourth International Meeting on Global Continental Pal- Corridor during the Last 30 k.y.: Sea Level Change and Human Adap- aeohydrology (GLOCOPH 2000), Hydrological Consequences of Global tation,” and INQUA 0501 “Caspian–Black Sea–Mediterranean Corridor Climate Changes: Moscow, Institute of Geography of Russian Academy during the Last 30 k.y.: Sea Level Change and Human Adaptive Strat- of Sciences, p. 34–36. egies” (4–16 October 2008; Bucharest, Romania, and Varna, Bulgaria): Khodakov, V.G., 1982, Aktualisticheskaya model’ Evropeiskogo pokrovnogo led- Bucharest, GeoEcoMar, p. 44–47. nika [An actualistic model of the European ice-sheet], in Gerasimov, I.P., and Domanitskiy, A.P., Dubrovina, R.G., and Isayeva, A.I., 1971, Reki i ozera Velichko, A.A., eds., Paleogeografi ya Evropy za poslednie sto tysyach let Sovetskogo Soyuza [Rivers and Lakes of the Soviet Union]: Leningrad, (Atlas-monografi ya) [Palaeogeography of Europe during the Last 100,000 Gidrometeoizdat, 104 p. (in Russian). Years (Atlas-Monograph)]: Moscow, Nauka, p. 48–62 (in Russian). Dury, G.H., 1964, Principles of Underfi t Streams: U.S. Geological Survey Pro- Kislov, A.V., and Toropov, P.A., 2006, Modeling of variations in river runoff fessional Paper 452-A, 67 p. on the East European Plain under different climates of the past: Water Dury, G.H., 1965, Theoretical Implications of Underfi t Streams: U.S. Geologi- Resources, v. 33, p. 471–482, doi: 10.1134/S0097807806050010. cal Survey Professional Paper 452-C, 43 p. Kroonenberg, S.B., Rusakov, G.V., and Svitoch, A.A., 1997, The wandering of Evstigneev, V.M., 1990, Rechnoy stok i gydrologicheskiye raschety [River the Volga delta: A response to rapid Caspian sea-level change: Sedimen- Flow and Hydrological Prognosis]: Moscow, Moscow University Press, tary Geology, v. 107, p. 189–209, doi: 10.1016/S0037-0738(96)00028-0. 304 p. (in Russian). Kvasov, D.D., 1979, The late Quaternary history of large lakes and inland seas Faustova, M.A., 1984, Late Pleistocene glaciation of European USSR, in of Eastern Europe: Annales Academiae Scientarium Fennicae, ser. A III, Velichko, A.A., ed., Late Quaternary Environments of the Soviet Union: v. 127, p. 1–71. Minneapolis, University of Minnesota Press, p. 3–12. Lane-Serff, G.F., Rohling, E.J., Bryden, H.L., and Charnock, H., 1997, Post- Faustova, M.A., and Chebotareva, N.S., 1969, Degradatsiya valdaiskogo glacial connection of the Black Sea to the Mediterranean and its relation oledeneniya, Belorusskaya SSR i Smolenskaya oblast’ [Degradation of to the timing of sapropel formation: Paleoceanography, v. 12, p. 169–174, the Valdai glaciation, Belorussian SSR and Smolensk region], in Gera- doi: 10.1029/96PA03934. simov, I.P., ed., Posledniy lednikovyi pokrov na severo-zapade Evropeis- Leonov, Yu.G., Lavrushin, Yu.A., Antipov, M.P., Spiridonova, Ye.A., Kuzmin, koi chasti SSSR [The Last Ice Sheet in the Northwestern European Part of Ya.V., Jull, E.J.T., Burr, S., Jelinowska, A., and Chalie, F., 2002, New age the USSR]: Moscow, Nauka, p. 151–176 (in Russian). data on sediments of the transgressive phase of the early Khvalyn trans- Gerasimov, I.P., ed., 1969, Posledniy lednikovyi pokrov na severo-zapade Evro- gression of the Caspian Sea: Doklady Earth Sciences, v. 386, p. 748–751. peiskoi chasti SSSR [The Last Ice Sheet in the Northwestern European Mangerud, J., Jakobsson, M., Alexanderson, H., Astakhov, V., Clarke, G., Hen- Part of the USSR]: Moscow, Nauka, 322 p. (in Russian). riksen, M., Hjort, C., Krinner, G., Lunkka, J.-P., Möller, P., Murray, A., Downloaded from specialpapers.gsapubs.org on September 18, 2012

Surface runoff to the Black Sea from the East European Plain 25

Nikolskaya, O., Saarnisto, M., and Svendsen, J.I., 2004, Ice-dammed Svezhentsev, Y.S., 1993, Radiocarbon chronology for the Upper Paleolithic lakes and rerouting of the drainage of northern Eurasia during the last gla- sites on the East European Plain, in Soffer, O., and Praslov, N.D., eds., ciation: Quaternary Science Reviews, v. 23, p. 1313–1332, doi: 10.1016/ From Kostenki to Clovis: New York, Plenum Press, p. 23–30. j.quascirev.2003.12.009. Svitoch, A.A., 1991, Kolebaniya urovnya Kaspiyskogo morya v pleistotsene Markov, K.K., and Suetova, I.A., 1964, Evstaticheskiye kolebaniya urovnya [Fluctuations of the Caspian Sea level in the Pleistocene], in Scherbakov, okeana [Eustatic changes of the ocean level], in Sovremennye Problemy F.A., and Svitoch, A.A., eds., Paleogeografi ya i Geomorfologiya Kaspi- Geografi i [Current Problems in Geography]: Moscow, Nauka, p. 24–34 yskogo Regiona v Pleistotsene [Palaeogeography and Geomorphology (in Russian). of the Caspian Region in the Pleistocene]: Moscow, Nauka, p. 5–100 Menabde, I.V., and Svitoch, A.A., 1990, O kharaktere soedineniya Kaspiysk- (in Russian). ogo i Chernogo morei v pozdnem pleistotsene [On the character of the Svitoch, A.A., and Yanina, T.A., 1997, Chetvertichnye otlozhenia poberezhiy connection between the Caspian and Black Sea in the late Pleistocene], in Kaspiyskogo morya [Quaternary Sediments on the Caspian Sea Coasts]: Lebedev, L.I., and Maev E.G., eds., Kaspiyskoye More: Voprosy Geologii Moscow, Rosselkhozacademia Press, 270 p. (in Russian). i Geomorfologii [Caspian Sea: Questions in Geology and Geomorphol- Szafer, W., 1946–1947, Flora plioceńska z Krościenka nad Dunajcem (The ogy]: Moscow, Nauka, p. 34–41 (in Russian). Pliocene fl ora of Kroscienko on Dunajec River): Rozprawy Wydzialu Obedientova, G.V., 1977, Erozionnye Tsikly i Formirovanie Doliny Volgi [Ero- matemat.-przyrodn: Polska Akad. Umiejet., Krakow, 72 B, 1, 162 p.; 2, sion Cycles and Formation of the Volga River Valley]: Moscow, Nauka, 213 p. (in Polish). 239 p. (in Russian). Tarasov, P.E., Peyron, O., Guiot, J., Brewer, S.V., Volkova, V.S., Bezusko, L.G., Ostrovsky, A.B., 1982, Paleogeografi cheskiye criterii prichin noveyshikh izm- Dorofeyuk, N.I., Kvavadze, E.V., Osipova, I.M., and Panova, N.K., 1999, eneniy paleogidrologicheskogo rezhima vnutrikontinental’nykh morei Last Glacial Maximum climate of the former Soviet Union and Mongolia [Palaeogeographical causes of the changes in the palaeohydrological reconstructed from pollen and plant macrofossil data: Climate Dynamics, regime of the intra-continental seas], in Kaplin, P.A., Klige, R.K., and v. 15, p. 227–240, doi: 10.1007/s003820050278. Chepalyga, A.L., eds., Kolebaniya urovnya morei i okeanov za 15000 let van Huzen, D., 2004, Quaternary glaciations in Austria, in Ehlers, J., and [Level Changes of the Seas and Oceans during the Last 15,000 Years]: Gibbard, P.L., eds., Quaternary Glaciations—Extent and Chronology: Moscow, Nauka, p. 102–112 (in Russian). Amsterdam, Elsevier, p. 1–13. Özsoy, E., Latif, M.A., Turul, S., and Ünlüata, Ü., 1995, Exchanges with the Varuschenko, S.I., Varuschenko, A.N., and Klige, R.K., 1987, Izmeneniya Mediterranean, fl uxes and boundary mixing processes in the Black Sea, rezhima Kaspiyskogo morya i besstochnykh vodoyemov v paleovremeni in Briand, F., ed., Mediterranean Tributary Seas: Bulletin de l’Institut [Changes of the Caspian Sea and Other Closed Lake Regimes in Palaeo- Océanographique, Monaco, Special No 15, CIESME (International Com- Time]: Moscow, Nauka, 240 p. (in Russian). mission for the Scientifi c Exploration of the Mediterranean Sea) Science Velichkevich, F.Yu., 1982, Pleistotsenovye Flory Lednikovykh Oblastei Series 1, p. 1–25. Vostochno-Evropeiskoi Ravniny [Pleistocene Floras of the Glaciated Panin, A.V., Sidorchuk, A.Yu., and Borisova, O.K., 2005, Flyuvial’nye Districts of the East European Plain]: Minsk, Nauka i Tekhnika, 239 p. protsessy i rechnoi stok na Russkoi ravnine v kontse pozdnevaldaiskoi (in Russian). epokhi [Fluvial processes and river runoff in the Russian Plain in the end Velichko, A.A., 1973, Prirodnyi protsess v pleistotsene [Natural Process in the of the late Valdai glacial epoch], in Yanina, T.A., ed., Gorizonty Geografi i Pleistocene]: Moscow, Nauka, 256 p. (in Russian). [Horizons of Geography]: Moscow, Moscow University Press, p. 114– Velichko, A.A., Berdnikov, V.V., and Nechaev, V.P., 1982, Rekonstruktsiya 127 (in Russian). zony mnogoletnei merzloty i etapov eyo razvitiya [Reconstruction of the Peltier, W.R., 1994, Ice age paleotopography: Science, v. 265, p. 195–201, doi: permafrost zone and stages of its development], in Gerasimov, I.P., and 10.1126/science.265.5169.195. Velichko, A.A., eds., Paleogeografi ya Evropy za poslednie sto tysyach let Popov, G.I., 1983, Pleistotsen Chernomorsko-Kaspiyskikh Prolivov [The Pleisto- (Atlas-monografi ya) [Palaeogeography of Europe during the Last 100,000 cene of Black Sea–Caspian Straits]: Moscow, Nauka, 216 p. (in Russian). Years (Atlas-Monograph)]: Moscow, Nauka, p. 74–81 (in Russian). Ryan, W.B.F., Pitman, W.C., III, Major, C.O., Shimkus, K., Moskalenko, V., Velichko, A.A., Faustova, M.A., Gribchenko, Yu.N., Pisareva, V.V., and Suda- Jones, G.A., Dimitrov, P., Görür, N., Sakınç, M., and Yüce, H., 1997, An kova, N.G., 2004, Glaciations of the East European Plain—Distribu- abrupt drowning of the Black Sea shelf: Marine Geology, v. 138, p. 119– tion and chronology, in Ehlers, J., and Gibbard, P.L., eds., Quaternary 126, doi: 10.1016/S0025-3227(97)00007-8. Glaciations—Extent and Chronology: Amsterdam, Elsevier, p. 337–354. San’ko, A.F., 1987, Neopleistotsen Severo-vostochnoi Belorussii i Smezhnykh Vlasov, V.K., and Kulikov, O.A., 1988, Radiotermolyuminestsentnyi metod Raionov RSFSR [The Neopleistocene of North-East Byelorussia and datirovaniya rykhlykh otlozheniy [Radio-thermo-luminescence method Neighboring Districts of the RSFSR]: Minsk, Nauka i Tekhnika, 178 p. of Non-Consolidated Sediment Dating]: Moscow, Moscow State Univer- (in Russian). sity Press, 72 p. (in Russian). Sidorchuk, A.Yu., and Borisova, O.K., 2000, Method of palaeogeographical Volkov, I.A., 1960, O nedavnem proshlom rek Ishim i Nura [On the recent past analogues in palaeohydrological reconstructions: Quaternary Interna- of the rivers Ishim and Nura]: Trudy Laboratorii Aerometodov AN SSSR tional, v. 72, p. 95–106, doi: 10.1016/S1040-6182(00)00025-2. [Proceedings of the Laboratory of Aeromethods, USSR Academy of Sci- Sidorchuk, A.Yu., Borisova, O.K., and Panin, A.V., 2001, Fluvial response to ences], v. 9, p. 15–19 (in Russian). the late Valdai/Holocene environmental change on the East European Volkov, I.A., 1963, Sledy moschnogo stoka v dolinakh yuga Zapadnoi Sibiri Plain: Global and Planetary Change, v. 28, p. 303–318, doi: 10.1016/ [An evidence of the powerful fl ow in the valleys of west Siberian rivers]: S0921-8181(00)00081-3. Doklady AN SSSR [Reports of the USSR Academy of Sciences], v. 151, Sidorchuk, A.Yu., Panin, A.V., and Borisova, O.K., 2008, Climate-induced p. 648–651 (in Russian). changes in river runoff on the north-Eurasian plains during the Late Gla- Walker, M.J.C., Björck, S., Lowe, J.J., Cwynar, L.C., Knudsen, K.-L., cial and Holocene: Water Resources, v. 35, p. 386–396, doi: 10.1134/ Wohlfarth, B., and INTIMATE Group I, 1999, Isotopic ‘events’ in the S0097807808040027. GRIP ice core: A stratotype for the late Pleistocene: Quaternary Science Sidorchuk, A.Yu., Panin, A.V., and Borisova, O.K., 2009, Morphology of river Reviews, v. 18, p. 1143–1150. channels and surface runoff in the Volga River basin (East European Plain) Winguth, C., Wong, H.K., Panin, N., Dinu, C., Georgescu, P., Ungureanu, G., during the Late Glacial period: Geomorphology, v. 113, p. 137–157, doi: Krugliakov, V.V., and Podshuveit, V., 2000, Upper Quaternary water level 10.1016/j.geomorph.2009.03.007. history and sedimentation in the northwestern Black Sea: Marine Geol- Svendsen, J., Alexanderson, H., Astakhov, V., Demidov, I., Dowdeswell, J., ogy, v. 167, p. 127–146, doi: 10.1016/S0025-3227(00)00024-4. Funder, S., Gataullin, V., Henriksen, M., Hjort, C., Houmark-Nielsen, Zagwijn, W.H., 1996, An analysis of Eemian climate in Western and Cen- M., Hubberten, H., Ingólfson, O., Jakobsson, M., Kjær, K., Larsen, E., tral Europe: Quaternary Science Reviews, v. 15, p. 451–469, doi: Lokrantz, H., Lunkka, J., Lyså, A., Mangerud, J., Matiouchkov, A., Mur- 10.1016/0277-3791(96)00011-X. ray, A., Möller, P., Niessen, F., Nikolskaya, O., Polyak, P., Saarnisto, M., Siegert, C., Siegert, M., Spielhagen, R., and Stein, R., 2004, Late Quater- nary ice sheet history of northern Eurasia: Quaternary Science Reviews, v. 23, p. 1229–1271, doi: 10.1016/j.quascirev.2003.12.008. MANUSCRIPT ACCEPTED BY THE SOCIETY 22 JUNE 2010 Printed in the USA Downloaded from specialpapers.gsapubs.org on September 18, 2012