Quaternary key-site Korchevo in Belarus: geology, paleontology and correlation

Journal Pre-proof Quaternary key-site Korchevo in Belarus: geology, paleontology and correlation Aleksander Sanko, Aleksander Motuzko, Andrey Vashkov, Andrey Dubman, Sergey Koloshich, Yuri Trifonov PII:

S1040-6182(19)30751-7

DOI:

https://doi.org/10.1016/j.quaint.2019.09.015

Reference:

JQI 7981

To appear in:

Quaternary International

Received Date: 31 August 2018 Revised Date:

12 July 2019

Accepted Date: 17 September 2019

Please cite this article as: Sanko, A., Motuzko, A., Vashkov, A., Dubman, A., Koloshich, S., Trifonov, Y., Quaternary key-site Korchevo in Belarus: geology, paleontology and correlation, Quaternary International, https://doi.org/10.1016/j.quaint.2019.09.015. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.

1

Quaternary key-site Korchevo in Belarus: geology, paleontology and correlation Aleksander Sanko a, Aleksander Motuzko a, Andrey Vashkov b, Andrey Dubman с, Sergey Koloshich a, Yuri Trifonov a a

Belarus State University (BSU), 4, Independence avenue, 220030, Minsk, Belarus

b

Geological Institute, Kola Science Center, Russian Academy of Sciences, 14, Fersman str., 184209, Apatity, Murmansk reg., Russia с

Geoenergetic, Domashevky lane, 9, 220030, Minsk, Belarus

abstract The Korchevo section with two layers of Quaternary Interglacial deposits is unique on the territory of Belarus. Deposits of this type occur in the middle part of the country at a depth of about 100 m on Narev moraine. These deposits in Korchevo were removed to the surface as a result of glaciotectonic processes and became available for paleontological studies. The location of fossil mammal fauna from Korchevo is the only one on the territory of Belarus, where the autochthonous complex of the ancient Middle Pleistocene mammals of Belarus studied on thousands remains of the of rodents teeth. The primitive root vole Mimomys intermedius (Newton) is the species of Alizarovian and Korchevian fauna. Seed flora, fauna of molluscs, insects and ostracods were the oldest in Middle Pleistocene. Paleontological studies were the basis for the allocation of stratigraphic units (Alizarovian Interglacial, Nevdian Glacial and Korchevian Interglacial) in the Middle Pleistocene of Belarus. Interglacial deposits of the key-site are very well correlated with Augustovian Interglacial formations in Poland. They correspond to parts of Cromer and Bavel complexes in the European stratigraphic scale of the Quaternary system.

Keywords Korchevian Interglacial, Middle Pleistocene, Augustovian Interglacial, mammal fauna, seed flora, malacofauna

1.

Introduction

The aim of the work is to summarize the results of the Korchevian Interglacial's research, to determine its place in the Quaternary stratum of Belarus and to make a correlation with the stratigraphic units of Western Europe and Poland. This study was carried out in the framework of the DATESTRA project (Database of QUATERNARY Terrestrial European Stratigraphy). The research area belongs to Belarus. Here Quaternary deposits are concentrated with the maximum thickness, the greatest stratigraphic completeness, a variety of genetic types and facies. In this regard, they are unique in Europe and can be considered as a reference (Goretcky, 1971). There are a rich set of glacial moraines and intervening interglacial lacustrine-bog deposits of the so-called “Glaciopleistocene” (Middle and Upper Pleistocene) in the region of Central Europe. The geological structure of these deposits, however, is often confusing. The strong variability of the thickness of sediments along the strike, the dislocation, the thinning and breaks in sedimentation do not allow the use of «sea» methods for stratification of sediments. Stratigraphic errors occur when calculating the distribution of moraine horizons in section, by counting from top to bottom. The main methods for the stratigraphic subdivision of Middle Pleistocene deposits in the region are still paleontological methods, which together with lithological, geochronological and other methods allow to date the deposits and show their place in the sequence of Quarternary glacial events. The key-site Korchevo is the oldest Interglacial deposits in the Glaciopleistocene. Deposits of similar age in the Quaternary of Central Belarus occur at depths usually exceeding

2

100 m. The problem of the age of these deposits are uderdiscussion since opening them in 1974 near the villages Korchevo and Alizarovshchina, Baranovichi district, Brest region (Voznyachuk et al.,1977). The Korchevian subhorizon selected in the composition of the Narevian horizon in the stratigraphic scheme of Quaternary deposits of Belarus of 2010 (Matveev et al., 2010). But so far, geologists continue to discuss at least three different views on the stratigraphic position of the key section of the Korchevian Interglacial. First, based on geological, faunistical, palynological data of N.A. Makhnach and O.P. Kondratene and also seed flora, Korchevian Interglacial is a termometer occurring after the Narev Glacial. The Korchevian Interglacial preceded the Yaseldian Glacial and belongs to the Middle Pleistocene according to the stratigraphic scheme of 2010. The second point of view of palynologists K. Mamakova and T. Rylova suggest that Korchevian Interglacial does not exist, and sediments of the section Korchevo refers to a younger Mogilevian Interglacial. The third point of view is justified in this article. It consists in the fact that deposits of Korchevo (after the Narevian Glacial) include two independent strata – Alizarovian and Korchevian Interglacials separated by periglacial sediments of small (Nevdian) Glacial. Ten locations with deposits of the Korchevian Interglacial know in Belarus: Korchevo (holostratotype), Romanjuki, Snov, Machulishchi, Dubentsi, Shchomyslitsa, Abchak, Upper Berezino, Sivkovo, Smolanka and a few sections, tentatively of this age (Fig. 1). Only the location of Korchevo among them is in artificial exposure, available for study in quarries. M.E. Zus first paid attention to this site and initiated the research.

Fig. 1. Map-scheme of site location with Korchevo sediments on the territory of Belarus: 1 – sections from the deposition of Korchevo type, 2 – sections, possible with deposits of Korchevo

3

type, 3 – sections with deposits of Augustovian Interglacial on the territory of Poland, 4 – sections, in which Karchevo deposits allocated conditionally, 5 – Korchevo key-site

4

2.

Brief history of geological studies of key-site Korchevo

Key-site Korchevo is well known in the region. L.N. Voznyachuk with colleagues (Voznyachuk et al., 1977; 1978) establish the oldest Korczevian Interglacial in Belarus Glaciopleistocene. Many scientific publications have been published since then. In 2014 T. V. Yakubovskaya, G. I. Litvinyuk and A. N. Motuzko published a monograph entitled «Korchevian Interglacial of Belarus» (Yakubovskaya et al., 2014a). The main results of the study key-site Korchevo will be presented in chronological order. 1. L.N. Voznyachuk with colleagues have identified a Korchevian Interglacial, characterized in the Middle Plestocene ancient fauna of rodents (Voznyachuk et al., 1977, 1978; Motuzko, 1977). They estimate the dislocated sediments in the Korchevo as a large erratic block with glacial-tectonic structure. 2. Alizarovian Interglacial, Novogrudokian Glacial (Periglacial) and Korchevian Interglacial horizons were selected in the section of Korchevo (Studies.., 1978). 3. G.I. Goretsky (Goretsky, 1980) criticizes the views of L.N. Voznyachuk about the multiplicity and age of the Korchevian Interglacial deposits. 4. L.N. Voznyachuk simplifies planned scheme of stratigraphic dissection of Korchevian erratic block (without Alizarovian Interglacial and Novogrudokian Glacial) in response to criticism. But he is firmly convinced that Korchevian (Minskian) time is the present interglacial period (Voznyachuk, 1981, 1985). 5. Scientists estimate the stratigraphic position of the Korchevo layers as: early Pleistocene (in accordance with the current stratigraphic scheme) by T.V. Yakubovskaya (Studies.., 1978), as part of the Naliboki series (Zus, 1980), as earlier than the Oka Glacial (Velichkevich, 1986), in the Beloviezhian horizon (Zus, 1989; Val’chik et al., 1990, etc.). 6. Authigenic pyrite (size 12-13 mm) present in the sediments of Korchevo. It indicates the younger age of the Korchevian Interglacial compared to the Dvoretz horizon of Belarus (Voznyachuk, Kovalev, 1979). 7. Detection of Korchevian Interglacial deposits at a distance of more than 2 km from the Korchevo quarry as a result of drilling conducted in 1984 (Baranovichi). The appearance of the point of view on the occurrence of Korchevo deposits in situ (Zus, 1991). 8. Paleontological methods were used in the study of the interglacial deposits in Korchevo site: palynology (analysis made by N.A. Makhnach, O.P. Kondratene, A.P. Shostak, K.I. Tarasevich, V.L. Shalaboda, Ya.K. Yelovicheva), seed flora (F.Yu. Velichkevich, T.V. Yakubovskaya, G.I. Litvinyuk), fauna of mammals (A.N. Motuzko, P.F. Kalinovsky), entomology (V.I. Nazarov), malacofauna (A.F. Sanko), ostracods (S.F. Zubovich). 9. The upper part of the sediments in the section Korchevo belongs to the paleomagnetic chron Brunhes (Sanko, Moiseev, 1996). 10. Correlation of Korchevian Interglacial with younger Mogilevian Interglacial of Pleistocene according to palynology analysis (Mamakowa, Rylova, 2007). 11. Discussion on the stratigraphic sequence and the age of the Korchevian Interglacial (Yakubovskaya, 2006; Yakubovskaya et al., 2014a). 12. Publication of the monograph «Korchevian Interglacial of Belarus» (Yakubovskaya et al., 2014a). 13. Discovery in Poland of Augustovian Interglacial deposits lying in the superposition – on the Narev moraine (Janczyk-Kopikowa, 1996; Winter, 2001, Ber, 2005; etc.). Correlation of the Augustovian Interglacial with the Korchevian Interglacial (Stachowicz-Rybka, 2011; Sanko, 2017 a, b).

5

3.

Material and methods

The key-site Korchevo is located in the quarry of the former brick factory «Malyshi» on the northern shore of the Servechskoe reservoir between the villages of Korchevo and Alizarovshchina (Baranovichi district, Brest region) about 6 km ENE from town of Gorodishche. It is also located in the south-eastern part of the Novogrudok Upland, in the zone of marginal glacial formations of the Sozh stage of the Pripyat glaciation of the Middle Pleistocene (Fig. 2). The quarry is located in the zone of Quaternary glacial tectonics. At present, the end glacial formations of the Pripyat glaciation (Middle Pleistocene) are developed here.

Fig. 2. Geological scheme of the surrounding area of key-site Korchevo: 1 – the morains of the Dneper glaciations reflecting the structure of the glacier, 2 – end moraine (sand and gravel) of the Sozh glaciations, 3 – fine and medium-grained alluvium sand of the Upper Pleistocene-Holocene, 4 – Holocene boggy deposits (peat), 5 –boreholes, 6 – cross-section lines, 7 – quarries near of the village Korchevo.

The thickness of Quaternary deposits varies between 150-200 m. Servetsky glacial trough or ice-cut hollow stands out in sub-Quaternary relief. It stretches from NNE to SSW and embedded in the Cretaceous deposits of 30-40 m. Korchevo quarries (Fig. 3) are located above the side of the glacier trough at the SW foot of the sand and gravel ridge with an absolute height of 202.4 meters. The complex of Cretaceous formations with a thickness of 20-40 m (Turonian and Cenomanian stages) and Paleogene-Neogene accumulations lie on the rocks of the crystalline basement in the vicinity of the Korchevo section. The thickness of lacustrine sediments up to 25 m lies on the green-gray moraine and overlaps the upper red-brown moraine. Dislocated glacial-tectonic structure with an angle of inclination of the layers 30-80° was clearly visible in the walls of the quarries (Studies..., 1978, с. 69). Layers are sometimes placed vertically or even thrown back. Lacustrine-boggy sediments are represented by clays, loams green-gray, olive-gray and blue-green colors with stretched interlayers of sandy loam, dark grey and black gyttia (Fig. 4).

6

Fig. 3. Scheme of the old and new quarry near the village of Kornevo showing the sampling site: 1- profile and its number, 2 – sections investigated by the palynological and paleocarpological methods, 3 – the walls of the quarry, from which a series of samples were studied by F.Yu. Velichkevich, 4 – points of generalized samples, 5 – place of collection of bone remains of mammals

Deposits in many places are fractured, with oxides of iron and manganese on cracks, with sliding mirrors, rare nodules of pyrite and rare pebbles of sedimentary rocks, with inclusions and lenses of sand. Much humanized interlayers of sandy loam and gyttya meet occasionally. Layers have a complex shape, transform into each other and difficult to bend. Interglacial deposits in a typical section (profile 3) consist of dark brown and brown-gray, detritus and peat gyttia with lenses of sand, as well as remains of plants, mollusks, insects, fish, rodents, with pyrite inclusions. These accumulations are overlain by glaciolacustrine and lacustrine clay, loam, sandy loam and sand, greenish-gray morainic sandy loam with pebbles and gravel of sedimentary and crystalline rocks. Moraine, as well as lake sediments, inclined at the same angle of 30-80°.

Fig. 4. The structure of Middle Pleistocene sediments in the key-site Korchevo from villages Korchevo and Alizarovshchina with profiles 1 and 2 in old quarry (Studies…, 1978, with a stratigraphic interpretation of the authors): a – discontinuous faults (shear planes); b – the place of gathering of the mammals remains; c – place sampling for seed flora and palynological analysis. The layers of the sediments: 1 – moraine of the Narev Glacial; 2 - fine-grained sand with layers of dislocated silt; 3 – loam and silt; 4 – Alizarovian Interglacial gyttia and silt with plant remains, molluscs, ostracods, insects, fish and rodents; 5 – Nevdian periglacial loam and sandy loam; 6 – Korchevian gyttia with nodules of pyrite, remains of plant, molluscs, ostracods, fish, and rodents; 7-8 – Yaseldian glacial loam, sandy loam and sand with interbedded of gyttia; 9 – Pripyatian (Dnieperian) moraine.

7

Drilling was carried out in the vicinity of the key-site Korchevo (see Fig. 2). Organogenic (Korchevian Interglacial) deposits were discovered almost 20 m lower than in the quarry at a distance of about 50 m (borehole 210, depth 90-94 m). Kоrchevian sediments in situ and no signs of glaciodislocations were discovered through the drilling of boreholes 211 and 212. Korchevian sediments in these boreholes revealed by one (Narev moraine) and overlap the three horizons of the moraine (Fig. 5-6). Texture of the Korchevian interglacial strata in all the boreholes differ in the uniformity of strata such as peat, gyttia, peaty sandy loam. In the quarries, the Korchevo lacustrine bed becomes dislocated. The complex of glacial and interglacial lacustrine sediments with Narev moraine involved here in building of glacio-tectonics structures, presumably of glacial erratic block.

Fig. 5. Column drilling of boreholes in the vicinity of key-site Korchevo along the line of boreholes 55 – 3357 (see fig. 2): 1 - moraine (boulder sandy loam and loam) of various Pleistocene glaciations; 2 – sand and gravel, 3 – loamy sand and loam; 4 – clay, 5 – gyttia and peat; 6 - Cretaceous formations (Turonian stage); 7 – granite and other crystalline rocks. Stratigraphic indexes: AR-PR - Archean-Proterozoic rocks of the crystalline basement; K2t Turonian layer of the Upper Cretaceous; P-Paleogene deposits; Q2nr - Narevian age; Q2kch – Korchevian age; Q2yas – Yaseldian age; Q2bz – Berezinian age; Q2pr - Pripyatian age; Q2dn – Dnieperian age; Q2sz - Sozhian age; Q3_4 – deposits of the Upper Pleistocene and the Holocene

8

The thickness of the Korchevian Interglacial deposits in profile 2 is 3.6 m, in profile 3 about 4 m, in cut 7 (new quarry) - about 4.5-5.5 meters. The total thickness of lacustrine-boggy deposits of all stratigraphic levels of erratic block reaches, according to study sections in the quarries and borings, of about 25 meters. The thickness of these deposits is slightly less in the continuous section of the borehole 210. The length of the lens of lacustrine sediments (fossil lake) along the valley of the river Servech is not less than 3 km, across the valley – more than 4 km.

Fig. 6. Column drilling of boreholes in the vicinity of key-site Korchevo along the line of boreholes 214 – 3260 (see fig. 2): 1-7 (see fig. 5)

The main conclusion of the review is as follows. The Key-site or holostratotype of Korchevian Interglacial is an erratic block. It is a complex structure made by the glacier, most likely, Yaselda Glacial, to the surface of the earth as a result of the disjunctive glacio-tectonic dislocations. The concept of the non-glacio-tectonic nature of the deposits of Korchevian Interglacial looks less convincing. A complex of paleontological methods was applied to study the key-site near the villages Korchevo and Alizarovshchina. This allowed reconstructing the sequence of accumulation of deposits, to trace and detail the natural course of development of aquatic and coastal fauna and flora. The complex of paleontological studies increases the stratigraphic value of the deposits of lacustrine sediments near the villages Korchevo and Alizarovshchina as a key-site.

4.

Results

Paleontological and stratigraphic studies of the key-site sediments of Korchevo was carried out in 6 profiles of the old and new quarries.

9

Fauna of mammals. More than a thousand remains of teeth of rodents and other animals were found in the sediments of the key-site Korchevo. The fauna of mammals was the primary basis in determining the relative age of the Korchevian Interglacial (Voznyachuk et al., 1977; Studies.., 1978). The evolution of the teeth of the genus Mimomys was clarified by the development of phylogenetic lines of voles (Motuzko, 1984, 1985). A comparison was made of the fauna from Korchevo with Pleistocene faunas from other localities of Europe. The result of this study was the setting up of a zonal scale for small mammals for Belarus, Poland and adjacent territories and the allocation of the Korchevian Interglacial faunistic zone: V. Lagurus transiens - Stenocranius hintoni (Nadachowski et al, 2003). The composition of this unique mammal fauna and its relationship with the Tiraspol fauna of Eastern Europe have been refined over the years. It looks like this now: Desmana sp., Myopus vel Lemmus sp., Sorex sp., Lagurini (Lagurus?) gen., Trogontherium cf. minus Newton, Mimomys intermedius (Newton), Trogontherium sp., Microtus (Stenocranius) hintoni (Kretzoi), Apodemus cf. flavicollis (Melchior), M. (Pallasiinus) protoeoconomus Rekovets, Cricetus cf. runtonensis Newton, M. (Stenocranius) aii.gregaloides (Hinton), Pliomys hintoni (Kretzoi), M. (Microtus) ex gr. hyperboreus-middendorffi, M. (Microtus) nivaloides (F. Major), Clethrionomys glareolus Schreber, Microtus sp., Clethrionomys sp., Archidiskodon sp., Lemmus sp., Cervus elaphoides Kahlke. Dicrostonyx sp., The place of the Korchevo mammalian fauna within the Middle Pleistocene is determined by the participation of root-tooth voles of Mimomys intermedius (Newton) species and the complete absence of representatives of non-root-tooth voles of the genus Arvicola. Interglacial deposits containing the teeth of Arvicola have a younger age (Bеlovezhian Interglacial and younger). Analysis of the morphology of the teeth of the root-tooth vole Mimomys intermedius (Newton) from Korchevo suggests that the structure of the dental system has a number of primitive morphological features. The connection of the tooth enamel of conides in the basal part is observed on the teeth of the Korchevo series. This distinguishes this vole from the roottoothed representatives of the species of gravel of Tiraspol age and the Latetiraspol fauna of the Don. The rest of the fauna does not contradict this conclusion. The predecessor of the Korchevian Interglacial fauna can be considered the fauna from the location of Zaleski IA (Zalesiaki, layers 2 and 9) in Poland, relating to the paleomagnetic Matuyama orthozone (Nadachowski et al., 2003). Remains of root-tooth voles of the genus Mimomys prevail in the collection. Their number reaches 80% of the total amount of all remains. The maximum number of the root-tooth voles remains accounts for interglacial sediments. Changes in the species composition of fauna from the bottom to top in the section reflect the evolution of fauna throughout the interglacial and periglacial environments (Fig. 7). Root-tooth voles from the dominant species Mimomys intermedius (Newton) prevailed over the grey forest voles of the genus Microtus in Alizarovian time. The presence Trogontherium cf. minus Newton was the hallmark of this fauna. Trogontherii has not been found in Novogrudokian (Nevdian) periglacial fauna. Root-toothed vole Mimomys intermedius (Newton) again began to dominate in the fauna of the Korchevian Interglacial. The ratio of beaver-trogontherii (Trogontherium sp.) and red forest voles (Clethrionomys glareolus Schreber) are increased. Desman (Desmana sp.) and root-tooth voles of the genus Pliomys are present in the structure of fauna. Hamsters (Cricetus cf. runtonensis Newton), lagurus steppe lemming Lagurini (Lagurus?) gen., hoofed and gray lemmings (Dicrostonyx sp., Lemmus sp.) appeared in Yaseldian Glacial.

10

Mimomys intermedius (Newton), Clethrionomys glareolus Schreber, Pliomys sp., Microtus (Stenocranius) hintoni (Kretzoi), M. (Pallasiinus) protoeoconomus Rekovets, Trogontherium cf. minus Newton are typical species of Alizarovian and Korchevian Interglacial fauna. Fauna of small mammals of similar composition belongs to the early Tiraspol fauna complex (beginning of the Middle Pleistocene). The fauna from the location of the Zalesiaki IA (layers 2, 9, paleomagnetic ortozone Matuyama) in Poland (Nadachowski et al., 2003) can be considered the predecessor of Korchevian Interglacial fauna. The fauna of small mammals of the Belovezhian (Roslavlian) Interglacial from the vicinity of Roslavl, Smolensk region of Russia (Nadachowski et al., 2003; Аgadzhanyan, 2009) is younger than the Korchevian fauna. At the time Roslavl fauna corresponds the final episode of Yaseldian Glacial, the entire interval of Belovezhian Interglacial and, possibly, initial stages of Zapadnodvinskian Glacial.

Fig. 7. Changes in the species composition of small mammals in the Korchevo key-site: 1 Mimomys intermedius (Newton), 2 - Microtus sp., 3 - Trogontherium cf. minus Newton The fauna of small mammals from Kozi Grzbiet in Poland, belonging to the Brunhes orthozone (Ber, 2005), is close in age to the Korchevian Interglacial fauna. The Korchevo fauna of mammals is close or even similar to the fauna of Il’inka-2 and Veret’e on the Upper Don (Krasnenkov, Agadzhanyan, 1975; Аgadzhanyan, 2009) in terms of evolutionary development. Both of these fauna is typical for the middle part of the Il’inska horizon of Russia.

11

Seed flora. Information on the composition of the seed flora of the location in D. Korchevo were obtained by F.Yu. Velichkevich, T.V. Yakubovskaya and G.I. Litvinyuk from the profiles in the walls of the old quarry Korchevo. These researchers determined the seed flora from eight series of samples from the profiles, as well as from the core of the three boreholes mentioned earlier. All series of samples contained floral remains. Seed flora is characterized by a large common composition, coinciding frequency of occurrence of the same species, the presence of the same guiding taxa and the same sequence of their appearance in the section. General characteristics of the Korchevo fossil flora is also high (compared to the Belovezhian Interglacials) exotic flora, the increase of species diversity in Alizarovian and Korchevian Interglacials, the absence of a clear seed flora with periglacial component during Novogrudokian (Nevdian) Glacial. The composition of macrophytes (inhabitants of mainly standing and slowly flowing waters) indicates that the remains accumulated in a lake. The depth of this interglacial lakes reached up 20 m. Paleobotanical studies in the Korchevo key-site determined 228 taxa. Features of the distribution of the remains of the seed flora in the cut and their composition led to the conclusion of paleocarpologists that Korchevian Interglacial had two climatic optimums - Alizarovian early and late Korchevian, separated by Novogrudok cooling (Yakubovskaya et al., 2014a). As will be shown further, these climatic optimums should be considered as independent interglacials. Seed flora of Alizarovian Interglacial (Optimum). This division is characterized by a combination of species Stratiotes goretskyi Wieliczk., Scirpus kreczetoviczii Wieliczk. and Ranunculus sceleratoides Nikit. ex Dorof. Each of these extinct species was a dominant of plant community. Azolla interglacialica Nikit. reached the maximum (more than 250 specimen) development in this interval. 102 taxa, of which 21 (30%) are extinct and 7 (10%) alien exotic species were identified in the flora of Alizarovian Interglacial. Species Brasenia sp. 1 may also be enrolled in endemics of Alizarovian time. Seed flora of Nevdian glacial (Novogrudok pessimum). Aquatic and littoral flora of the Novogrudokian pessimum is a qualitatively and quantitatively impoverished flora of the previous Alizarovian time. The flora of this interval consists of 71 taxa. The number of extinct species decreased to 12 (24%). The number of alien species was 4 (8%). Features of seed flora in combination with the lithological composition of sediments and their relatively small thickness, in all probability, indicate the interstadial rank of the investigated unit. Layers related to the stadial time are present in the structure of Novogrudok pessimum, but they do not contain seed flora macroremains. At the same time, palynological studies point to periglacial landscapes of stadiums of the Nevdian Glacial with the participation of the following representatives of tundra and steppes: Ericaceae, Saxifraga, Dryas, Papaver lapponicum (Tolm.) Nordh. Rubus chamaemorus L., Betula nana L. Seed flora of Korchevian Interglacial (optimum). This interval is characterized by the richest seed flora among other divisions of the key-site. The research identified 113 taxa, of which 22 (28%) are extinct and 8 (10%) alien exotics. The combination of extinct species is original, not repeated in the optima of other interglacials in Belarus. The following extinct species are Nymphaea sp. ext., Aldrovanda zussii T. V. Jakub., Stratiotes goretskyi Wieliczk., Caulinia antiqua (T. V. Jakub.) T. V. Jakub., Scirpus kreczetoviczii Wieliczk. not found in the later Belovezhian Interglacial. T.V. Yakubovskaya et al., (Yakubovskaya et al., 2014a) identifies three floristic complexes in the composition of the flora of Korchevian Interglacial: lower, medium and upper. Palynological studies. N.A. Makhnach (Studies..., 1978) O.P. Kondratene (Kondratene, Zus, 1979), K. Mamakova and T.B. Rylova (Mamakowa, Rylova, 2007) performed a sporepollen analysis of the key-site. Together they characterize the sediments of Alizarovian Interglacial, Nevdian (Novogrudokian) Glacial, Korchevian Interglacial and Yaselgian Glacial (early phases). The data of the spore-pollen analysis of the Alizarovian Interglacial reflect only its final (late Interglacial) segment with spectra of forest type. The share of wood pollen reached 80% at this time (Fig. 8, layer 4). Dominant position had pine pollen (Pinus) with the presence of birch

12

pollen (Betula) and spruce (Picea). There is a small participation of pollen Ulmus, Tilia, Corylus and Alnus, almost complete absence of oak and hornbeam pollen. The pollen of all deciduous trees disappears at the top of the layer. Pollen zone can be described as Pinus - Betula - Q. T., upward, alternating Pinus - Betula. Palynological spectra of the sediments of Nevdian Glacial allow to interpret the natural environment first with cold and then dry climate and tundra-steppe vegetation. The Nevdian spectra contain significant amounts of pollen from herbs, mainly wormwood, and representatives of periglacial vegetation such as Papawer lapponicum (A. Tolm.) Nordh., Rubus chamaemorus L, Saxifraga and Dryas. Deposits of the Korchevian horizon, judging by the spore-pollen diagram N.A Makhnach (see Fig. 8), is a real interglacial hornbeam type. The optimum spectra of this Interglacial include two zones: oak and elm, alder and hornbeam. O.P. Kondratene (Kondratene, Zus, 1979) obtained similar spectra for Korchevian Interglacial, but with some minor differences. She pointed to the presence of pollen from rare plants such as Pinus sect. Cembrae Spach., P. sect. Strobus Shaw., Picea sect. Omorica Willkm., Celtis?, Vitis? and Ilex, Selaginella sp. 1 (the species is recorded in Upper Pliocene sediments of section Dvoretz on the river Dneper), Azolla sp. et al. K. Mamakova and T.B. Rylova (Mamakowa, Rylova, 2007) performed a palynological study of Korchevian Interglacial deposits at the key-site and came to unexpected conclusions. They believe that such features of palynograms as the culmination of Carpinus pollen before the culmination of Quercetum mixtum together with the dominance of Quercus, a large amount of Alnus pollen at and a small amount of Coryllus characterize the Mogilevian Interglacial. They correlate the succession of vegetation pollen in Korchevo with the second (younger) Ferdinandovian Interglacial and the second (younger) Augustovian Interglacial in Poland, considering them to be the same age.

Fig. 8. Spore-pollen diagram of the Korchevo key-site deposits, cut 1 (old quarry), analysis N.A. Makhnach (Studies.., 1978): 1 - loam; 2 - sandy loam; 3 - sand; 4 - gyttia carbonate; 5 gyttia detrital; 6 - pollen of trees and shrubs; 7 - spores; 8 - pollen of grasses; 9 - Picea; 10 - Pinus, 11 Betula; 12 - Artemisia, 13 - Chenopodiaceae; 14 - Papaver lapponicum; 15 - Rubus chamaemorus; 17 Sphagnum; 18 – Lycopodiaceae

Malacofauna. The shells of mollusks identified at three points from the dark gray gyttia related only to the Korchevian Interglacial. Malacofauna was of the same type, which indirectly indicates its age at the same time and in a similar physical and geographical environment. The shells have undergone significant fossilization, resulting in most of them, especially large, turned into a fragment. The operculas of Bithynia Leach, and also shell small and young forms are only

13

well preserved. The malacofauna of Korchevo includes 23 taxa (3 terrestrial and 20 freshwater ones). It is a freshwater fauna from an ecological point of view. It contains species from different ecological groups. Every ecological molluscs occupy a dominant position. They are able to live in stagnant and flowing water. Their number is huge, about 90% of the total number of specimens (Fig. 3.1). River species (reophles) forming the second environmental group. Mollusks of permanent water bodies, as well as amphibiotic forms and terrestrial species are present in a small amount of 1-4%. This ratio of ecological groups of mollusks allows concluding, that the fauna of Korchevo comes from a relatively small and strongly overgrown reservoir, periodically flooded with river waters. The old oxbow was, apparently, such a reservoir. Reophilic mollusks Viviparus sp., Valvata naticina Menke, Pisidium supinum Schmidt indicates the alluvial (?) origin of fauna and fauna-containing deposits of Korchevo. The sharp predominance of the Bithynia opercula above the shells and the triangular shape of the shells of the genus Pisidium Pfeiffer, in particular P. moitessierianum Paladilhe is also a sign of a significant dynamics of the aquatic environment. The water body of Korchevo was inhabited mostly common Palaearctic and Holarctic species. Extinct species of mollusks are represented by two taxa Parafossorulus crassitesta (Brömme) and Pisidium sulcatum (Wood), which is 8.7% of the species composition of the fauna. The number of extinct species in the Korchevo fauna could be large if the whole large shells Viviparus Montfort and Unio Philipsson were preserved. The presence in the fauna of a large number (up to 25.9%) of excentric opercula of Parafossorulus crassitesta (Brömme) (Fig. 9) determines the relative age of the Korchevo Interglacial deposits. Thick-walled operculas of Parafossorulus crassitesta (Brömme) are characteristic representatives of the Early and Late Eopleistocene sediments in the South of the Russian plain (Steklov, Chepalyga, 1969).

Fig. 9. Operculas of Parafossorulus crassitesta (Brömme) from the Korchevo kay-site

The Parafossorulus crassitesta (Brömme) remains are found only in the most ancient layers of the Middle Pleistocene. The shells were not establish in the sediments of the Belovezhian Interglacial and its correlated interglacials, including interglacials of the Cromer complex in Britain, The Netherlands, France, Germany and Denemark (Meijer, Preece, 1996), carbonate deposits of Ferdinandov Interglacial in Poland (Alexandrowicz, 1991), stratotype site Borki (Belovezhian Interglacial) in Belarus, Roslavlian Interglacial (=Belovezhian Interglacial) sediments near the villages Kirilly and Podrudnyansky (Shik, 1961), Muchkapian Interglacial sediments of the Don (Krasnenkov, 1984). Shells of this species are widely represented in Augustovian deposits of Poland, correlated with Korchevian layers of Belarus (Sanko, 2017b). It follows that the species Parafossorulus crassitesta (Brömme) became extinct after Korchevo's time, most likely during the Yaseldian glaciation. Entomofauna and fauna of ostracods. V.I. Nazarov (1990) established 27 taxa in the entomofauna of the key-site of the Korchevian Interglacial. He points to the complex nature of climate change in Korchevo, the presence of pessimum, corresponding to the small glaciation of Fennoscandia. Complexes of insect species of the lower and upper Optima, according to V.I. Nazarov, are close, but do not repeat each other. Later V. I. Nazarov gives updated data on the entomofauna of the Korchevian Interglacial (Velichkevich et al., 1996). Thermophilic species of

14

Chlaenius tristis Schall., Oodes helopoides F, Pterostichus melanarius Ill., Odocantha melanura L, Colymbetes paukulli Er., Donacia obscura Gyll, Hydronomus alismatis, Marsh. and extinct species Morychus michailovski Nazarov, Normandia sp., Dorcadion sp. identified in the composition of this fauna of insects. The fauna of ostracods was studied by S. F. Zubovich (Zubovich, 1979) in the typical location of the Korchevian Interglacial on profile 2. Shells of the ostracods were found in separate sediment intervals at a depth of 4.0-8.8 m, corresponding to layers of 5-8 key-site (see fig. 4). 23 taxa of ostracods identified in the composition of the fauna. All of the representatives of this fauna are identified as modern species, and all are marked «ex gr.» and «aff.». Three types of shells are identified as unknown species of the genera Herpetocypris, Candoniella and Limnocythere. Based on these data, the author concludes an Early Pleistocene (in accordance with the stratigraphic scheme of 1983) age of the Korchevian fauna. In a later publication (Yelovicheva, Zubovich, 2007) S.F. Zubovich notes the presence of relicts of the Late Pliocene in the Korchevian fauna of ostracodes. .

5.

Discussion

Deposits of the Korchevo key-site were found near the surface on the Novogrudok Upland and were available for research in a quarry for clay extraction of a brick factory for a long time. Karchevo quarries are recultivated some years ago. The deposits of Korchevian Interglacial are also known in the section of Romanyuki on Novogrudok Upland at a depth of 188.5-192.0 m (Litvinyuk, Yakubovskaya, 2010). Significant differences in the depth of the Korchevo deposits, as well as the presence of Cretaceous rocks as erratic blocks on the Novogrudok Upland and in the vicinity of Korchevo, in particular, is an additional argument in favor of their displaced (erratic) position in the Quaternary thickness. Finding a deposits of the Korchevo Interglacial in a complex glaciotectonic structure gave rise to a discussion about the nature of glaciodislocations (erratic block or glacial scales), the age of deposits and even the possibility of using paleontological materials. The deposits are, of course, deformed, and in disturbed bedding, but it retained the main features of the sequence of stratification, the ratio of the underlying and overlapping glacial accumulations. This makes it possible to stratify sediments and consider it a key-site. Geological and paleontological materials obtained earlier and partly sanctified in this publication, let us go back to the original point of L.N. Voznyachuk and co-authors (Studies…, 1978) on the allocation of stratigraphic units in section Korchevo. We are talking about identification of the validity of the Alizarovian and Korchevian Interglacial horizons and intervening Novogrodokian (Nevdian) glacial horizon. The term «Novogrudok horizon» is used in the stratigraphic scheme of Quaternary deposits of Belarus 2010, so it is replaced with the «Nevda horizon». These vision are reflected in the new version of the stratigraphic scheme of Quaternary deposits of Belarus (Table 1). The establishment of the Augustovian Interglacial in Poland, near the Western border with Belarus (Ber, 2005) was a great affirmation of the proposed stratification of the Korchevo key-site. Augustovian deposits together with the Narev moraine were found in the lower part (at depths exceeding 100 m) of the Quaternary strata by a number of boreholes (see fig 1). Deposits of stratotypes of the Korchevian and Augustovian Interglacials are in the zone of perfect development of the Quaternary glacial formation, with the most complete set of glacial horizons of the Pleistocene in Belarus. Interglacial deposits of both stratotypes were rich in paleontological remains, which allows reconstructing the paleogeographic situation of that time with a high degree of reliability. The possibility of correlation between the stratotypes of the Korchevian and Augustovian Interglacials is due to the accumulation of the same (lacustrine) genetic type and similar stratification. At the same time, deposits in Augustovian Interglacial uncovered a series of boreholes at depths greater than 100 m in superposition (on the oldest Narev moraine of the Glaciopleistocene). Augustovian Interglacial, according to a comprehensive study of borehole cores is regarded by Polish geologists as a single interval (the

15

horizon) with two climatic Optima, separated by a phase of cooling. Lower climatic optimum on pollen and spore diagrams of Korchevian and Augustovian Interglacials refers to the type of oak and elm, the top is a type of hornbeam interglacial. The same type of spore-pollen diagrams describes for the Belovezhian interglacial of Belarus and Ferdinandovian Interglacial of Poland, which was the argument for palynologists (Mamakova, Rylova, 2007) to compare them in regard of the age. However, Augustovian and Ferdinandovian Interglacials, as shown by H. Winter (Winter, 2009), have significant differences (more «cold» lower and more «warm» upper climatic optimum, differences in the cyclicity of the appearance of thermophilic woody plants, as well as a significant role of spruce in the forests), which do not allow us to consider Augustovian and Ferdinandovian deposits of the same age. Table 1

Stratigraphy Cromer

Wester Europe (Zagwijn, 1996)

Bavel

Middle Pleistocene Early Pleistocene

Matuyama

Brunhes

Palaeomagnetism

Stratigraphic subdivision of the Early and Middle Pleistocene of Belarus and Poland and its correlation

Holstein Elster Noordbergum Glacial C Rosmalen Glacial B Westerhoven Dorst Leerdam Linde Bavel Menap Waal Eburon Tiglian Pretiglian

Belarus, A.F. Sanko

Poland, according to L. Lindner, A. Ber with addition

Alexandrian Berezian Magilevian Nizniskian Borkian Yaseldinian Korchevian Nevdian Alizarrovian Narevian Rogachevian Zhlobinian Elnian Vselubskian Dvoretskian Olhovian

Mazoveckian Sanian 2 Ferdinandow 2 Ferdinandow 1/2 Ferdinandow 1 Sanian 1 (Nidian) Augustovian Bebzhian Zharnovian Narevian ? ? Celestynovian Otvockian Ponuzhycian Różcian

We have an opportunity to compare malacofauna of Korchevian stratotype and Augustovian. The malacofauna of both units are freshwater-lacustrine. It characterizes flowing water bodies. The Pliocene relics of Fagotia wuesti Meijer and Parafossorulus crassitesta (Brömme) are of interest in these fauna in a stratigraphic way. Shells of both species have been found in Polish sections. At the same time, it was found that Fagotia wuesti Meijer occupies an ecological niche only in the «lower climatic optimum», and in the «upper climatic optimum», judging by the section of Żarnowo, behaves as an extinct species. Apparently, for this reason the species was not recorded by S. Skompski in the composition of the Augustovian malacofauna of the Szczebra, as well as malacofauna Sucha Wies and Czarnucha (Skompski, 2009). The species Parafossorulus crassitesta (Brömme) lived in Augustovian and Korchevian reservoirs for two «climatic Optima». Both species disappeared, and most likely became extinct at the beginning of Yaselda (Nida) glaciations. They do not appear in the younger interglacials, including the Belovezhian in Belarus and Ferdinandovian in Poland.

16

Stratigraphic rank of Korchevian and Augustovian Interglacials in the understanding of «lower climatic optimum», «intermediate cooling», «upper climatic optimum» can not be considered accurate and correspond to the real paleogeographic situation. The experience of paleogeographic reconstructions of the Quaternary of the zone of continental glaciations testifies to the need to be based on one optimum in the interglacial intervals of the Pleistocene. Two optimum in interglacial is a erroneous paleogeographic performance. Here is an example as an analogy. Thermokarst depressions common in the modern relief of the vicinity of Minsk, filled with lacustrine-boggy sediments of Muravian (Eemian), Poozerje (Vistulian) and Holocene age. Paleontologists never attribute the deposits of such a section to «Interglacial with two Optima» and intermediate cooling. The Augustovian stratoregion of Poland is unique in that between its two «climatic Optima» or two interglacials there is a real cold Pleistocene interval in the rank of an independent glacial horizon. A similar sequence of horizons previously mentioned by L.N. Voznyachuk (Studies…, 1978), to be shown on the Korchevo location on territory of Belarus. Based on the principle of one optimum in the interglacial, we propose the following interpretation of the stratigraphic subdivisions occupying the position between the Narev and Yaselda Glacial (Sanko, 2017a). Correlation of deposits of the Korchevian and Augustovian key-sites looks convincing on paleontological data. Now let us pay attention to the data of paleomagnetic studies. Deposits the Korchevo key-site is, apparently, in the area of the polarity change of paleomagnetic chrons Brynhes-Matuyama following correlation with Augustovian and Zharnovian Interglacials. Paleomagnetic studies of the Korchevian Interglacial deposits in the old quarry, performed by E.I. Moiseev, showed their direct magnetization corresponding to the Brunhes chron (Sanko, Moiseev, 1996). Deposits of other stratigraphic units of the key-site were not studied due to their dislocation. As shown by A. Ber (Ber, 2005), lacustrine deposits in the Augustovo stratoregion of Poland accumulated in the interval, where there was a polarity change from Brunhes to Matuyama chron. J. Nawrocki (Nawrocki, 2009) performed paleomagnetic analysis of the full series of lacustrine deposits of Czarnucha section in the Augustów stratoregion. He notes that lacustrine sediments have mainly secondary magnetization as a result of diagenetic processes. But single samples with a minus inclination, found in the lower part of the section, represent the original paleomagnetic record. The presence of such samples indicates that part of the sequence was accumulated during the reverse magnetization of the Matuyama chron. The data of paleomagnetic and paleontological studies allow us to make an assumption concerning the stratigraphy and correlation of the Korchevo and Augustów sections. Since Augustovian and Korchevian Interglacial are perfectly correlated according to paleontological data, it can be assumed that the paleomagnetic boundary of Brunhes-Matuyama is also present among the deposits of the Korchevo key-site. The upper interglacial strata (Korchevian Interglacial in Belarus and Augustovian in Poland) have a direct magnetization (chron Brunhes). Lower interglacial strata (Alizarovian Interglacial in Belarus and Zharnovian in Poland) have a reverse magnetization (chron Matuyama). In this regard, we can assume that the change (transition) of two chrons occurred in the interval separating them, that is Nevda Glacial in Belarus or Bebzha Glacial in Poland. The obtained data allow to conduct correlation on the basis of the ratio paleomagnetism with marine isotope stages based on the SPECMAP curve (Bassinot et al., 1994) and Stratigraphic chart for the Quaternary-2011, published by the Subcommission on Quaternary Stratigraphy. According to these data, the direct-magnetic deposits of the Korchevian Interglacial should be compared with MIS 18-19 or Interglacial 1 Waardenburg of the Cromer series of North-Eastern Europe. In this case, the Nevda Glacial horizon (Belarus) and its Polish analog, Bebzha Glacial (Augustovian I/II), should be compared with the first (upper) division of Bavel, namely, the Dorst interval (MIS 20). The reverse magnetized deposits of the Zharnovo Interglacial in Poland and its analog Alizarovian Interglacial in Belarus should be correlated with

17

the MIS 21 (Leerdam) of the Bavel complex. Narev interval (deposits of the Narevian Glacial) is stratigraphically below. It should be compared with the Linge division of the Bavel complex (MIS 22). If the Narev horizon is correlated with the Menap interval (MIS 34-40), as suggested by A. Ber (Ber, 2005) and L. Lindner (Lindner et al., 2004), in this case, we should allow a long hiatus between Narev moraine and Interglacial deposits of Zharnovian Interglacial (see table 1). But geological studies suggest a close connection in the accumulation of these deposits. A large stratigraphic hiatus is clearly absent in this interval.

6.

Conclusions

Geological and paleontological materials obtained from the Korchevo key-site allow us to draw the following conclusions. 1. The result of this study was to clarify the relative age and reconstruct the sequence of accumulation close to the original, lake. 2. The dislocated lacustrine strata in shallow quarries near village Korchevo is estimated as a glacial erratic block of the scale-thrust structure. Deposits of the same age and genesis were found in situ near the key-site at a depth of about 100 m. They lie here on one (Narev moraine) and overlap with three moraine horizons (see figure 5, borings 211 and 212). 3. Geological and paleontological research on the key-site was the basis for stratigraphic units of the erratic block: Narevian Glacial, Alizarovian Interglacial, Nevdian Glacial, Korchevian Interglacial, Yaseldian Glacial horizons. 4. The stratigraphic rank of interglacial deposits of the key-site as «Lower climatic optimum», «Intermediate cooling», «Upper climatic optimum» (Yakubovskaya et al., 2014a, b) cannot be considered accurate and correspond to the real paleogeographic situation for the zone of continental glaciations, which is the central part of the territory of Belarus. We believe that climatic optimums and intermediate cooling of the Korchevo section have the rank of independent stratigraphic subdivisions as a horizon. Deposits of Nevdian Glacial, exactly like the deposits of Poozerje (Vistulian) Glacial in the Novogrudok Upland presented only periglacial (stadial and interstadial) layers. Nevdian Glacial is the so-called «small glaciation» in the territory of Central Belarus. 5. Interglacial deposits of the Korchevo key-site have more ancient age, than Belovezhian and especially Mogilevian Interglacial deposits. This conclusion is confirmed by paleontological materials of both climatostratigraphic and evolutionary nature. At the same time deposits of the Korchevoy key-site are an integral part of the Middle Pleistocene of Belarus, which is considered as the glacial Pleistocene or Glaciopleistocene. 6. Interglacial deposits of the Korchevo key-site turned out to be similar, but not identical with the Belovezhian and Mogilevian Interglacial deposits of Belarus by the type of palynological diagrams. Alizarovian and Belovezhian Interglacial spore-pollen diagrams have oak-elm type diagrams, and Korchevian and Mogilevian – hornbeam type. This was the starting point of palynologists K. Mamakova and T.B. Rylova (Mamakova, Rylova, 2007) to combine them by age. However, this is an erroneous belief. T.V. Yakubovskaya rightly pointed to this error in an article (Yakubovskaya, 2006). Different age of the Alizarovian and Belovezhian Interglacial deposits also follows from the fact that Alizarovian sediments were formed in Matuyama paleomagnetic ortozone and Belovezhian sediments - in Brunhes ortozone. 7. Correlation of the Korchevo key-site deposits is almost certain with the Augustovian series of deposits of Poland. The section of the Augustovo stratoregion complement in some aspects of geological pattern appearing in the Korchevo section. Seed flora, palynology and malacofauna of Augustovian units in Poland (Winter, 2001, 2009; Khursevich et al., 2005; Khursevich, Marciniak, 2007; Ber et al., 2009; Stachowicz-Rybka, 2011) have a great similarity with paleontological data from the Korchevo key-site. Although Polish geologists consider the Augustovian Interglacial to be a single stratigraphic subdivision, they compare it with the

18

Waardenburg interval of the Kromer complex and all the divisions of the Bavel s. I. of the Netherlands (Ber, 2005; Lindner, Marks, 2008; Ber et al., 2009). 8. Correlation of the Korchevo key-site deposits looks less certain with deposits in the other neighboring countries. Analogues of Korchevian Interglacial (in the old sense) in Russia are either the 15th MIS (Borisov, 2009), or the 17th MIS (Velichko et al., 2005, 2012), or together the 17th-19th isotope-oxygen stages (Zubakov, 1992, 1993; Ber et al., 2009). Korchevian Interglacial has similarities with several strata of interglacial rank of Russia in the composition of seed flora and features of spore-pollen diagrams. Akatovian Interglacial is considered as an analogue of Korchevian Interglacial by many researchers (Fursikova et al., 1992; Shik, 2003; Velichko et al., 2005). F.Yu. Velichkevich (Velichkevich, 1982) correlates Korchevian Interglacial with Akulovian Interglacial of Russia. The seed flora of the Korchevo type was found in the sediments of the lower part of the Kyamenian Interglacial in Lithuania (Velichkevich et al., 1998; Kisieliene, 2002). O.P. Kondratene (Kondratene, 1996) compares Korchevian Interglacial with younger Interstadial Bine on the basis of palynological data. References Аgadzhanyan A.K., 2009. Small mammals of Pliocene-Pleistocene of the Russian plain (Melkie mlekopitayushchie pliotsen-pleistotsena Russkoj ravniny). M.: Science, 1-676 (in Russian). Alexandrowicz, S.W., 1991. The malacofauna of the Ferdynandovian interglacial in the Belchatow outcrop (Central Poland). Folia quaternaria. № 61-62. 93–99. Bassinot, E.C, Labeyrie, L.D., Vincent, E. et al., 1994. The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal. Eard Planet. Sci. Lett. Vol. 126. 91-108. Ber, A., 2005. Polish Pleistocene stratigraphy. A review of interglacial stratotypes. Geologie en Mijnbouw. Vol. 84, № 2. 61-76. Ber, A., Lisitsky, St. Winter, H., 2009. Lower Pleistocene stratigraphy of northeastern Poland on the basis of studies of lake deposits from the Sucha Wies (Elk lakeland) and Czarnucha (Augustów plain) sections with reference to the areas of Russia, Lithuania and Belarus (Stratygrafia dolnego Pleistocenu Polnocno-wschodniej Polski na podstawie badan osadow jesiornych z profili Sucha Wies (Pojezierze Elckie) i Czarnucha (Rownina Augustowska) w nawiazaniu do obszarow Rosji, Litwy i Bialorusi). No. 435. 23-36 (in Polish). Borisov B. A. 2009. General stratigraphic scale of the Ouarternary. Key-site of the European part of Russia (Obshchaya stratigraficheskays shkala kvartera. Opornye razrezy evropejskoj chasti Rossii). VI Vserssijskoe soveshchanie po izucheniyu chetvertichnogo perioda, Novosibirsk, 1923 Oct. 2009, Novosibirsk, 84-88 (in Russian). Fursikova, I.V., Pisareva, V.V., Vlasov V.K., Kulikov, O.I., Yakubovskaya T.V., 1992. Key site of the Pleistocene at the village of Okatovo in Western Moscow suburbs (Opornyj razrez pleistotsena u d. Okatovo v Zapadnom Podmoskov’e). Stratigrafiya fanerazoya tsentra Vostochno-Evropejskoj platformy). Edited by S.M. Shik. M., 59-82 (in Russian). Goretsky, G.I., 1971. About the main directions of the study of the Anthropogene of Belarus in the nearest years (Ob osnovnych napravleniyach izucheniya antropogena Belarusi v blizhajshie gody). Antropogen Belarusi. Minsk: Science and technology, 235-245 (in Belarus). Goretsky, G.I., 1980. Features of the paleopothamology of glacial areas (on the example of Belarusian Poneman). (Osobennosti paleopotamologii lednikovych oblastej (na primere Belorusskogo Poneman’ya). Minsk: Science and technology, 1-288 (in Russian). Janchik-Kopikowa, Z., 1996. Warm periods in mezoplejstocenie North-Eastern Poland (Ciepłe okresy w mezoplejstocenie północno-wschodniej Polski). State Inst. Geol. 373: 49-66 (in Polish). Khursevich, G., Nita, M., Ber, A., Sanko, A., Fedenya, S., 2005. Palaeoenvironmental and climatic changes during the Early Pleistocene recorded in the lacustrine-boggy-fluvial sediments at Komorniki, NE Poland. Polish Geological Institute. № 16. 35-44. Khursevich, G., Marciniak, B., 2007. Diatom succession in lacustrine sediments of the lower and middle Pleistocene sediments inboderland of Poland and Belarus. Materials of the V-th Polish-Belarus seminar, Warszawa, Poland, 2-5 July, 2007. Warszawa, 4-8.

19 Kisieliene, D., 2002. Palaeocarpological complexes of Lithuania Quaternary and their stratigraphical significance: Abstract of doctoral dissertation. Instytute of Geology and Geography. Vilnius, 128. Kondratene, O.P., Zus, M.E., 1979. Palynological characteristics of the Korchevo section (Palynologicheskaya charakteristika razreza Korchevo). Novoe v geologii antropogena Belarusi. Minsk: Science and technology 30-34 (in Belarus). Kondratene, O. 1996. Stratigraphy and paleogeography of the Lithuania Quaternary on paleobotanical data (Stratigrafiya i paleogeogtafiya kvartera Litvy po paleobotanicheskim dannym. Vilnius, 1209 (in Russian). Krasnenkov, R.V., 1984. Land and freshwater mollusks (Nazemnye i presnovodnye molluski). Opornye razrezy nizhnego pleistotsena bassejna Verchnego Dona. Voronezh, VGU, 150-164 (in Russian). Krasnenkov, R.V., Agadzhanyan, A.K., 1975. The Lower Pleistocene of Middle Don (Nizhnij pleistotsen Srednego Dona). Byulleten’ Komissii po izucheniyu chetvertichnogo perioda. No. 44. 69-83 (in Russian). Lindner, L, Gozhik, P., Marciniak, В., Marks, L, Yelovicheva, Ya., 2004. Main climatic changes in the Quaternary of Poland, Belarus and Ukraine. Geological Quaterly. Vol. 48, № 2. 97-114. Lindner, L., Marks, L., 2008. Pleistocene stratigraphy of Poland and its correlation with stratotype sections in the Volhynian upland (Ukraine). Geochronometria. 31. 31-37. Litvinyuk, G.I., Yakubovskaya T.V., 2010. Sediments of the Korchevian Interglacial and stratigraphy of the Quaternary strata of the Novogrudok upland in the Nevda river basin (Otlozheniya korchevskogo mezhlednikov'ya i stratigrafiya chetvertichnoj tolshchi Novogrudskoj vozvyshennosti v bassejne r. Nevda). Litosfera. No. 1 (32). 31-42 (in Russian). Mamakowa, K., Rylova, T.B., 2007. The interglacial from Korchevo in Belarus in the light of new palaeobotanical studies. Acta palaeobotanica. Vol. 47, № 2. 425-453. Matveev, A.V., Sanko, A.F., Velichkevich, F.Yu., Rylova T.B. et al., 2010. Quaternary system (Quaternary). (Chetvertichnaya sistema (kvarter)). Stratigraficheskie schemy dokembrijskich i fanerozojskich otlozhenij Belarusi: ob’yasnitel’naya zapiska. Ed. S.A. Kruchek, A.V. Matveev, T.V. Yakubovskaya etc. Minsk: GP "Belnigri", 186-204 (in Russian). Meijer, T., Preece, R.C., 1996. Malacological data relating to the stratigraphical position of the Cromerian. The early Middle Pleistocene in Europe. Ed. C. Turner, Balkema (Rotterdam): 53-82. Motuzko, A.N., 1977. The first finding of the Lower Pleistocene fauna of mammals in Belarus (Pervaya nachodka nizhnepleistotsenovej fauny mlekopitayushchich v Belorussii. Vestnik MGU. Ser. Geografiya. No. 4. 13-15 (in Russian). Motuzko, A.N., 1984. Lower Pleistocene fauna of rodents on the territory of Belarus (Nizhneplejstotsnovaya fauna gryzunov na territorii Belarusi). Antropogen Evrazii. M., 194-199 (in Russian). Motuzko, A.N., 1985. Rodents of the Anthropogene of Belarus and adjacent territories (Gryzuny antropogena Belorussii i sopredel’nych territorij. Problemy pleistotsena. Minsk: Science and technology, 173-188 (in Russian). Nadachowski, A., Motuzko, A.N., Ivanov, D.L., 2003. Stratigraphy of Quaternary deposits of Belarus, Poland and neighboring territories based on the study of small mammals (Stratigrafiya chetvertichnych otlozhenij Belarusi, Pol'shi i sosednich territorij na osnovanii izucheniya melkich mlekopitayushchich). Stratigrafiya i paleontologiya geologicheskich formatsij Belarusi. Edited by A.A. Makhnach and others. Minsk: Institute of geological sciences of NAS of Belarus, 217-224 (in Russian). Nawrocki, J., 2009. The results of palaeomagnetic investigations of lacustrine deposits from the Czarnucha section (Augustów plain, northeastern Poland). Wyniki badañ paleomagnetycznych osadów jeziornych z profilu Czarnucha (równina Augustowska, pólnocno-wschodnia Polska). Biuletyn pañstwowego Instytutu geologicznego. 435, 69-74 (in Polish). Nazarov, V. I., 1990. About the first findings of Early Pleistocene insects on the territory of Novogrudok upland (O pervych nachodkach rannepleistotsenovych nasekomych na territorii Novogrudskoj vozvyshennosti). Doklady AN BSSR. Vol. 34, No. 1. 75-78 (in Russian). Sanko, A.F., 2017a. Correlation of the Korchevo Interglacial deposits of Belarus and Augustovian Interglacial of Poland (Korrelaciya otlozhenij korchevskogo mezhlednikov’ya Belarusi iavgustovskogo interglaciala Pol’shi). Sovremennye problemy geochimii, geologii i poiskov mestorozhdenij poleznych iskopaemych: materialy Mezhdunarodnoj nauchnoj konferetsii,

20 posvyashchennoj 110-letiyu so dnya rozhdeniya akademika K.I. Lukasheva, 23-25 maya 2017 g. Ed. O.V. Lukashev [i dr.]: Minsk: Law and Economics. Part 1. 116-119 (in Russian). Sanko, A.F., 2017b. Augustovian Interglacial of Poland according to study of mollusk fauna (Аvgustovskij interglacial Pol’shi po dannym izucheniya fauny molluskov). Zhurnal Belorusskogo gosudarstvennogo universiteta. Geografiya i geologiya. No. 2, 163-174 (in Russian). Sanko, A.F., Moiseev, E.I., 1996. The first definition of paleomagnetic boundaries Brunhes - Matuyama in Belarus (Pervoe opredelenie paleomagnitnoj granitsy Brunes - Matuyzma v Belarusi). Doklady AN Belarusi. Vol. 40, No. 5, 106-109 (in Russian). Skompski, S., 2009. Pleistocene fauna in the Sucha Wies (Elk lakeland) and Czarnucha (Augustów plain) sections, northeastern Poland (Fauna z osadów plejstoceńskich w stanowiskach Sucha Wieś (Pojezierze Ełckie) i Czarnucha (Równina Augustowska), pólnocno-wschodnia Polska. Biuletyn Panstwowego Instytutu Geologicznego. 435. 85–96 (in Polish). Stachowicz-Rybka, R., 2011. Flora and vegetation changes on the basis of plant macroremains analysis from an early Pleistosene lake of the Augustow Plain, NE Poland // Acta Palaeobotanica. № 51 (1). 39-103. Studies of the Anthropogene of Belarus, 1978. (Dasledavanni antrapagenu Belarusi). Ed. V.A. Kuznetsov. Minsk: Science and technology, 1-200 (in Belarus). Steklov, A.A., Chepalyga, A.L., 1969. The main stages of development of the continental mollusks of the Anthropogene of the USSR (Osnovnye etapy razvitiya kontinental’nych molluskov antropogena SSSR). Osnovnye problem geologii antropogene Evrazii. M.: Nauka, 71-81 (in Russian). Shik, S.M., 1961. New data on the Middle Pleistocene Interglacial deposits of the Smolensk region (Novye dannye o srednepleistotsenovych mezhlednikovych otlozheniyach Smolenskoj oblasti). Materialy Vsesoyuznogo coveshchaniya po izucheniyu chetvertichnogo perioda. M.: Publishing house of the USSR, Vol. 2. 252-258 (in Russian). Val'chik, M.A., Zus, M.E., Fedenya, V.M., Karabanov, A.K., 1990. End moraine of the Belarusian ridge (Kraevye obrazovaniya Belorusskoj gryady). Minsk: Science and technology, 1-162 (in Russian). Velichkevich, F.Yu., 1982. Pleistocene floras of glacial regions of the East European plain (Plejstotsenovye flory lednikovych oblastej Vostochno-Evropejskoj ravniny). Minsk: Science and technology, 1-230 (in Russian). Velichkevich, F.Yu., 1986. About Early Pleistocene Interglacial flora of Korchevo section in Novogrudok Upland (О ranneplejstotsenovoj mezhlednikovoj flore razreza Korchevo na Novogrudskoj vozvyshennosti). Doklady AN BSSR. Vol. 30, No. 3, 255-258 (in Russian). Velichkevich, F.Yu, Sanko, A.F., Rylova, T.B., Nazarov, V.I., et al., 1996. Stratigraphic scheme of Quaternary (Anthropogene) deposits of Belarus (Stratigraficheskaya schema chetvertichnych (antropogenovych) otlozhenij Belarusi). Stratigraphy. Geological correlation. Vol. 4, No. 6, 75-87 (in Russian). Velichkevich, F, Kondratiene, O., Kisieliene, D., 1998. The new data on Early Pleistocene paleocarpology in Lithuania. Geologija. Vilnius, № 25, 92-101. Velichko, A.A., Pisareva, V.V., Faustova, M.A., 2005. Glaciation and interglacial East European plain in the early and middle Pleistocene. Stratigraphy (Oledeneniya i mezhlednikovya VostochnoEvropejskoj ravniny v rannem i srednem pleistocene. Stratigraphy. Geological correlation. T. 13, No. 2. 84-102 (in Russian). Velichko, A.A., Pisareva, V.V., Faustova, M.A., 2012. Correlation of glacial events of glacial and periglacial Pleistocene in Eastern Europe in connection with problems of chronostratigraphy (Korrelaciya lednikovycj sobytij lednikovogo i periglacialnogo pleistotsena Vostochnoj Evropy v svyazi s problemami chronostratigrafii). Byulleten' Regionalnoj mezhvedomstvennoj stratigraficheskoj komissii po tsentry i yugu Russkoj platform. Issue. 5, 149-161 (in Russian). Voznyachuk, L.N., 1981. Main stratigraphic subdivisions of Quaternary deposits (Osnovnye stratigraficheskie podrazdeleniya chetvertichnych otlozhenij). Materialy po stratigrafii Belorussii. Minsk, 137-151 (in Russian). Voznyachuk, L.N., 1985. Problems of Glaciopleistocene of the East European plain (Problemy glaciopleistotsena Vostochno-Evropeiskoj ravniny). Problemy pleistocena. Ed. M.A. Val'chik, A.F. Sanko. Minsk: Science and technology, 8-55 (in Russian). Voznyachuk, L.N., Makhnach, N.A. Motuzko, A.N., Velichkevich, F.Yu. et al., 1977. Lower Pleistocene deposits of v. Korchevo on Novogrudok Upland in Belarus and their stratigraphic and

21 paleogeographic significance (Nizhnepleistocenovye otlozheniya d. Korchevo na Novogrodskoj vozvyshennosti v Belorussii i ich stratigraficheskoe i paleogeograficheskoe znachenie. Doklady AN BSSR. Vol. 21, No. 11, 1025-1028 (in Russian). Voznyachuk, L.N., Makhnach N.A., Motuzko, A.N., Velichkevich, F.Yu. et al., 1978. New data on paleogeography of the Early Pleistocene of the glacial region of the East European plain (Novye dannye po paleogeografii rannego pleistotsena lednikovej oblasti Vostochno-Evropeiskoj ravniny). Doklady AN SSSR. T. 239, No. 1, 154-157 (in Russian). Voznyachuk, L. N., Kovalev, V. A. 1979. About the possibility of using pyrite nodules to specify the age of Late Cenozoic freshwater sediments of the Russian plain (O vozmozhnosti ispolzovaniya konkretsij pirita dlya utochneniya vozrasta pozdnekajnozojskich presnovodnych otlozhenij Russkoj ravniny. Doklady AN BSSR. Vol. 23, No. 2, 164-167 (in Russian). Yakubovskaya T.V., 2006. About question of age of the Korchevian Interglacial (К voprosu o vozraste korchevskogo mezhlednikov’ya). Litosfera. № 2 (25). 155-158 (in Russian). Yakubovskaya, T.V., Litvinyuk, G.I., Motuzko, A.N., 2014а. Korchevian Interglacial of Belarus (Korchedckoe mezhlednikov’e Belarusi). Minsk). 1-161 (in Russian). Yakubovskaya, T.V., Litvinyuk, G.I., Motuzko, A.N., 2014b. Correlation of Korchevian Interglacial of Belarus and neighboring regions on the results of the study of fauna and flora (Korelaciya korchevskogo mezhlednikov’ya Belarusi i sosednich regionov po rezultatam izucheniya fauny i flory). Litosfera. 1(40). 125-135 (in Russian). Yelovicheva Ya., Zubovich S., 2007. Features of paleogeographic development of the territory of Belarus and Ukraine in the Pleistocene (Osobennosti paleogeograficheskogo razvitiya territorii Belarusi i Ukrainy v pleistotsene. Problemy srednepleistotsenovogo interglaciala, Lutsk, 12-16 sept. 2007 г. Lviv: LNU, 129-162 (in Ukraine). Winter, H., 2001. New section of the Augustovian Interglacial in North-Eastern Poland. (Nowe stanowisko interglacialu awgustowskiego w polnocno-wschodniej Polsce). UAM, Ser. Geogr., 64: 439–450. Winter, H., 2009. A pollen succession from the Czarnucha section (Augustów plaine) and its significance for the Lower Pleistocene stratigraphy of northeastern Poland (Sukcesja pylkowa z profilu Czarnucha (Rownina Awgustowska) i jej znaczenie dla stratigrafii dolnego plejstocenu polnoczno-wschodniej Polski). Biuletyn Panstwowego Instytutu Geologicznego. № 435. 109-120 (in Polish). Winter, H., Khursevich, G., Fedenya, S., 2008. Pollen and diatom stratigraphy on the lacustrine-fluvialboggy sediments from the profile at Domuraty, NE Poland. Geological Quarterly. Vol. 52, № 3. 269-280. Zagwijn, W.H., 1996. The Cromerian Complex Stage of the Netherlands and correlation with other areas in Europe. In: Turner, C. (ed.): The Early Middle Pleistocene in Europe. Balkema (RotterdamBrookfield): 145-172. Zubakov, V.A., 1992. Glacial-interglacial cycles of the Pleistocene of the Russian and Siberian plains in pollen diagrams (Lednikovo-mezhlednikovye tsikly Pleistocene Russkoj i Sibirskoj ravnin v pyl’tsevych diagrammach). SPb. 1-122 (in Russian). Zubakov, V.A., 1993. Climate and stratigraphy correlation of the common scale of the European Pleistocene (Klimatostratigraficheskaya korrelatsiya i obshchaya shkala evropeiskogo pleistotsena). Stratigrafiya. Geologichskaya korrelatsiya. Vol. 1, No. 3. 109-119 (in Russian). Zubovich, S.F., 1979. The first data on the fossil ostracodes of the Korchevo section (Pervye dannye ob iskopaemych ostrakodach razreza Korchevo). Novoe v geologii antropogena Belarusi. Minsk: Science and technology, 51-53 (in Belarus). Zus, M. E., 1980. Geological situation of the Korchevo glaciodislocations (Geologicheskaya situatsiya rajona korchevskich glatsiodislokatsij. Problemnye voprosy geologii antropogena i neogena Belorussii. Minsk: Science and technology, 28-36 (in Russian). Zus, M.E., 1989. Paleogeography and palaeogeomorphology of the Novogrudok upland (Paleogeografiya i paleogeomorfologiya Novogrudskoj vozvyshennosti. Paleogeografiya kajnozoya Belorussii. Minsk: Science and technology, 31-40 (in Russian). Zus, M.E., 1991. Novogrudok upland: geological structure, glaciotectonics, relief, stages of formation (Novogrudskaya vozvyshennost’: geologicheskoe stroenie, glaciotektonika, rel’ef, etapy formirovaniya). Minsk: Science and technology, 1-126 (in Russian).

Conflict of interest 1.

2.

We assume that the Korchevian Interglacial (in the old sense) is a complex system consisting of three stratigraphic units: Alizarovian Interglacial (horizon), Nevdian Glacial (horizon) and Korchevian Interglacial (horizon). T.V. Yakubovskaya (Yakubovskaya et al., 2014) continues to consider Korchevian Interglacial in the old sense as a single horizon with two climatic optima. The deposits of the Korchevian Interglacial in Korchevo key-site lie at depth of about 100 m in central Belarus. Therefore, we regard that the outcrops of Korchevo Interglacial deposits are an erratic block, in contrast to the point of view of some authors about their occurrence in situ.