Annually-laminated lake sediments (varves) are among the most reliable archives for high-resolution paleoenvironmental reconstruction. However, the Russian Plain has remained a gap in the global distribution of varve chronologies. This preliminary study presents the first Younger Dryas Early Holocene varve chronology from Lake Kasplya (western part of the Russian Plain). A 17.3 m sediment core (Kas-17) was retrieved in 2022, of which the 9.6-15.2 m interval revealed well-preserved biochemical varves. Thin-section microscopy and diatom identification confirmed the annual nature of laminations. Independent chronologies were developed through manual varve counting, and radiocarbon dating. The results indicate a floating varve chronology of 4745 +/- 325 annual layers (with cumulative uncertainties of 6.84%), spanning ca. 12.1-7.4 ka BP. Anchoring to radiocarbon age-depth models demonstrates a high level of agreement, with discrepancies within 10%. This record from Lake Kasplya provides a high-resolution terrestrial archive for the Russian Plain and underscores the potential of similar lakes to provide varve-based reconstructions of paleoclimate.

In the south of the East European Plain, within the boundaries of the city of Elista, a loess-paleosol sequence has been discovered in which the Late Pleistocene of the Salyn interglacial paleosol has been uncovered. The aim of the study is to obtain new knowledge about pedogenesis and conditions of paleosol formation in one of the poorly studied regions of the East European Plain during the Late Pleistocene. Multi-proxy analysis (particle-size distribution, magnetic susceptibility, loss on ignition, color, and micromorphology) with high-resolution sampling along the Elista section was applied to reconstruct the paleosol cover. Two OSL dates were obtained to refine the age, which confirmed the paleosol age consistent with MIS 5e. In the loess-paleosol sequence of the Elista section, the Salyn interglacial paleosol (MIS 5e) is morphologically similar to Calcic Kastanozems (or Aridisols), characteristic of the modern soil cover in the study area. It is revealed that the interglacial soil formation was passing into the << waning >> stage, which was a precursor of climate change and the onset of the ice age. In this transitional interval, the Salyn interglacial paleosol, due to increased climate aridization, developed according to the type of modern Calcic Gypsic Kastanozems (or Gypsids). In hyperarid conditions, its profile corresponded to Calcisols (or Calcids).

Hyperspectral imaging of lake sediment cores offers a promising analytical method being both high-resolution and non-destructive. In this study, we investigate the potential of an industry-standard hyperspectral (VNIR) camera combined with a custom developed software package to provide indirect data on past changes in sediment accumulation conditions of a mid-elevation lake in the Caucasus Mountains. The software allows for automated core fragment stitching, crack removal and spectral analysis. We introduce the technique of wavelength correlation mapping as a tool to trace within-core variations of spectral properties (i.e. absorption features). The absorption feature around 670 nm wavelength marks a characteristic distinction between organic-rich and organic-poor sections of the studied sediment core. This part of the spectrum corresponds to absorption of electromagnetic radiation by chlorophyll a , a pigment ubiquitous in photosynthetic organisms. In this study, we use the techniques of relative absorption band depth (RABD) and area (RABA) with various spectral spans to calculate and compare the 670 nm derived spectral indices. The selected RABD 660;670 index serves as a high-resolution (229 μm/px) proxy for downcore variations of autochthonous organic matter and provides the reconstruction of lake productivity for the period 3000–1000 BP with subannual resolution. The results are supported with independent biogenic proxies – total organic carbon, loss-on-ignition and concentration of bromine in the sediment.

Bottom sediments of the Lake Plescheevo is a valuable lake record for the central part of the East European Plain. During this study, we analyzed the lithological characteristics of the upper 4 m of the lake sediment and calculate the sedimentation rate and mass accumulation rate of the lace sediments during last 3500 years. We established that the main part of the increase in the mass accumulation of the Lake Plescheevo bottom sediments is due to the silicate deposits associated with the introduction of terrigenous material into its water area. High values of mass accumulation rates about 3500-3000 cal BP. correspond to a stage of high fluvial activity for the East European Plain. The rapid increase in the rate of mass accumulation rate in the last few decades may be associated with the anthropogenic impact - possibly with the influence of a dam on the Vyoksa River flowing into the lake.

The article presents the results of a palynological study of Lake Chukhlomskoye bottom sediments. Pollen analysis in combination with the results from 14C and 137Cs dating made it possible to reconstruct the main stages of changes in plant communities in the Kostroma Volga region at the end of the Pleniglacial and during the Late Glacial: 19.5–16.9 cal. ka BP – periglacial steppe, 16.9–14.7 cal. ka BP – birch periglacial forest-steppe, 14.7–12.7 cal. ka BP – spruce and birch-spruce forests and open woods with periglacial-steppe and meadow communities, 12.7–11.7 cal. ka BP – birch periglacial forest-steppe with rare participation of spruce.

Based on the lithostratigraphic and geomorphological approach, the study of lake level fluctuations in Nero and Seliger over the past 15,000 years was conducted. Common features of level changes were revealed: deep regression at the end of the late glacial period and early Holocene, intensive rise in level in the early-middle Holocene, stabilization (with a slight upward trend) in the late Holocene. Similar features in level changes were revealed in the history of a number of lakes in Germany and Scandinavia. A connection was found between lake level fluctuations and the intensity of fluvial processes in the center of the East European Plain.

In the center of the East European Plain, lake sediments provide the most detailed and high-resolution paleoarchives of the Late Pleistocene and Holocene periods. However, not all lake sediments can be used to reliably reconstruct regional paleoclimate and landscape changes. Factors such as the shape of the lake basin, the type of rocks beneath it, the number and flow of tributaries, and the vegetation present all play a role in determining the rate and composition of sedimentation in lake deposits, creating a unique record of the local environmental conditions. The Sarskoe Bog Basin has promising potential for providing a high-resolution record of the Late Pleistocene period. The core sample collected from the central part of the swamp met all expectations, but during the geophysical study of the geological structure and search for the maximum depth of lake sediments, it was found that the reference well was not in the most appropriate location. The first geophysical surveys conducted in the bog have improved our understanding of the paleorelief of the basin and will allow us to choose a location for the main well that is suitable for our research objectives.

The climatostratigraphic scale of the Upper Middle Pleistocene in the northwest of the East European Plain contains a number of controversial issues, one of which is the position of the Likhvin (Holstein) Interglacial and lesser warm (interstadial) climatic events. To approach this problem, we have studied two sections of Quaternary deposits, Bolshaya Kosha (a well-known and long-studied natural exposure) and Nazarovo (a new, previously unknown section studied in a borehole), in which warm intervals of the Middle Pleistocene are recognized. In both sections, we performed lithological and paleobiological (carpological, spore-pollen) analyses and luminescence dating. In the Bolshaya Kosha section, seeds of the extinct species Caulinia goretskyi were revealed, which allowed us to attribute the obtained IRSL (ca 250–260 ka) dates to the post-Likhvin Bolshaya Kosha interstadial. The sum of data let us propose that both our IRSL and recently published 230Th/U dates (ca 240–290 ka) underestimate the age by 10–15%, and the post-Likhvin Kosha interstadial deposits were formed in the late MIS 9. In the Nazarovo section, palynological study showed the conditions of a relatively warm interstadial, with a change in the composition of vegetation from northern to middle taiga forests. According to IRSL dating, the section was formed in the MIS 10 late glacial between 330–370 ka. The two studied interstadials bracket the Likhvin (Holstein) Interglacial and sedimentary units in the Bolshaya Kosha section are proposed to have formed in MIS 9e.

Presented study aims to investigate paleolimnological conditions of Lake Kasplya in northwestern European Russia. An annually-laminated deposits were analyzed with 14C dating, thin section study and varve counting using a semi-automated method. An annual structure is expressed in one or two pairs of layers per year (light – diatomite and calcite, dark – organomineral detritus with pyrite concretions). Differences in the structure of Early Holocene and Middle Holocene varves indicate changing paleolimnological conditions of the water body, while the disappearance of varves around 6.7 thousand years ago suggests the cessation of stable lake stratification. Due to the peculiarities of sediment structure, the obtained varve chronology is older compared to the radiocarbon sedimentation model (3,5 thousand years versus 2,5 thousand years).

The paper discusses new palynological data obtained from the bottom sediments of Lake Chukhlomskoye (Kostroma region). The location of the lake beyond the limits of the Late Valdaian ice sheet made it possible to reconstruct the vegetation changes during the maximum phase of the glaciation and compare them with previously obtained data from sediments of Lake Galichskoye. 25-21 thousand calibrated years BP, the region was occupied by open periglacial steppe with limited participation of birch and spruce open forests in the most protected habitats, with continuous spread of permafrost. Climatic reconstructions based on the modern geographical analogue of the fossil pollen flora indicate that mean annual temperature in the region was about ˗4 °C (7 °C below modern), and annual precipitation was at near-present level.

This research focuses on the reconstruction of Lake Kasplya (Smolensk oblast) history in Holocene based on the interpretation of the bulk inorganic and organic geochemistry records. We derived bulk inorganic geochemistry for the lake bottom sediment record using X-ray fluorescence and conducted a principal component analysis (PCA) using geochemistry and lithogenic data. Based on PCA, we obtained a three-component model, which describes 73% of the variance. Each component represents a factor that contributes to the geochemical and lithogenic records: lithogenic, chemically altered matter, and organic matter inputs to the lake.

The paper discusses the structure of the bottom sediments of Lake Chukhlomskoye (Kostroma region, Russia). The results of complex lithological analysis and 14C AMS dating (TOC) of the sediments revealed in two boreholes located in different geomorphological positions of the bottom relief allowed to reconstruct stages and conditions of sedimentation in the lake. Mass accumulation rate (MAR) was calculated. High values of MAR correspond to 25.4–17.5 cal ka BP (up to 0.192 g/cm2 per year), a sharp decrease of MAR corresponds to 17.9–16.7 cal ka BP, and another stage of sediment influx occurred in Younger Dryas. Holocene MAR is low (0.001–0.053 g/cm2 per year).

For the first time, a high-resolution record of natural events of the Late Glacial and Early Holocene (14150–9730 cal BP) was obtained for the Upper Kama basin based on sedimentary succession in Novozhilovo Lake (Kama–Keltma lowland). The results of the reconstruction of sedimentation setting, based on paleobotanical and sedimentological analyses, as well as radiocarbon dating, are presented. The beginning of formation of the lake was apparently preceded by a period of predominantly alluvial morpholithogenesis, which presumedly corresponded to the Late Pleniglacial. There are four stages in the evolution of the lake basin: the first three were characterized by lacustrine-alluvial sedimentation that was predominantly minerogenic, and the fourth stage was marked by typical lacustrine organogenic sedimentation. The first stage covered the Bølling–Allerød interstadial period from 14 150 to 13 500 cal BP, which was characterized by the accumulation of sand under conditions of high water flow. At the Allerød–Younger Dryas boundary, bioproductivity increased significantly. During the second stage (13 500–12 420 cal BP), water exchange slowed down and organomineral lake sediment formed. The third stage of the transitional sedimentation refers to the Younger Dryas–Early Holocene (12 420–10 700 cal BP). During that time, alluvial inputs predominated, with a decrease in the organic matter content. Finally, the fourth stage of the eutrophic lake (10 700–9730 cal BP) was characterized by a high organic matter content in the sediment and the aleurite fraction increased in the grain-size composition.

The article presents the results of a multiproxy study of a sedimentary sequence located on the lacustrine-alluvial plain west of Lake Nero (Yaroslavl region). The investigated 2 m-long core made it possible to reconstruct environmental changes since the Allerød to the Late Holocene. Previously poorly studied Preboreal deposits in this area have a significant thickness in the core (0.4 m). The obtained materials help fill the gap in understanding of the vegetation history in the Rostov lowland at the turn of the Late Glacial and Holocene and during the Early Holocene. The study is based on several paleogeographic methods: spore-pollen analysis, botanical composition analysis of peat, diatom analysis, loss-on-ignition, and radiocarbon dating. It was found that after 14.3 cal. ka BP sparse spruce-birch forests were widespread, open spaces were occupied by herbaceous communities. Since 13.7 cal. ka BP, as a result of a significant cooling, the open areas expanded, sparse birch forests dominated in combination with steppe and tundra associations. About 12.1 cal. ka BP a lowland reed wetland began to form at the site. It transformed into a reed-sedge wetland after 10.9 cal. ka BP. During the interval of 12.1–11.5 cal. ka BP, the landscapes of the periglacial forest-steppe were gradually replaced by pine-birch forests. The climate was colder than today, but with the tendency to warming compared to the Late Glacial stage. Short-term cooling 11.5–11.2 cal. ka BP led to a new expansion of open herbaceous communities, but the spread of forests continued after 11.2 cal. ka BP. Starting from 9.8 cal. ka BP, the role of broadleaf species increased in the woods; mixed pine-birch forests with oak, elm, and linden dominated in the surrounding area. In the interval 7.9–5.2 cal. ka BP, climate conditions were warmer than modern ones. This led to the spread of spruce-pine forests with birch and thermophilous deciduous trees. After 5.2 cal. ka BP the vegetation cover was dominated by spruce forests with pine, birch, and broadleaf species.

The article presents the results of a multiproxy study of a sedimentary sequence located on the lacustrine-alluvial plain west of Lake Nero (Yaroslavl region). The investigated 2 m-long core made it possible to reconstruct environmental changes since the Allerød to the Late Holocene. Previously poorly studied Preboreal deposits in this area have a significant thickness in the core (0.4 m). The obtained materials help fill the gap in understanding of the vegetation history in the Rostov lowland at the turn of the Late Glacial and Holocene and during the Early Holocene. The study is based on several paleogeographic methods: spore-pollen analysis, botanical composition analysis of peat, diatom analysis, loss-on-ignition, and radiocarbon dating. It was found that after 14.3 cal. ka BP sparse spruce-birch forests were widespread, open spaces were occupied by herbaceous communities. Since 13.7 cal. ka BP, as a result of a significant cooling, the open areas expanded, sparse birch forests dominated in combination with steppe and tundra associations. About 12.1 cal. ka BP a lowland reed wetland began to form at the site. It transformed into a reed-sedge wetland after 10.9 cal. ka BP. During the interval of 12.1–11.5 cal. ka BP, the landscapes of the periglacial forest-steppe were gradually replaced by pine-birch forests. The climate was colder than today, but with the tendency to warming compared to the Late Glacial stage. Short-term cooling 11.5–11.2 cal. ka BP led to a new expansion of open herbaceous communities, but the spread of forests continued after 11.2 cal. ka BP. Starting from 9.8 cal. ka BP, the role of broadleaf species increased in the woods; mixed pine-birch forests with oak, elm, and linden dominated in the surrounding area. In the interval 7.9–5.2 cal. ka BP, climate conditions were warmer than modern ones. This led to the spread of spruce-pine forests with birch and thermophilous deciduous trees. After 5.2 cal. ka BP the vegetation cover was dominated by spruce forests with pine, birch, and broadleaf species.

We describe materials from a new Paleolithic site, discovered in 2020 on the right bank of Mius estuary, near its confl uence with the Taganrog Bay of the Sea of Azov, in the southern outskirts of the village of Nikolaevo-Otradnoye, which is in the Neklinovksky District of the Rostov Region. The clearing of a 10-meter-high river-bluff revealed a complex stratigraphy of subaqueous and subaerial Late and Middle Pleistocene rocks. Horizons with lithics and faunal remains were identifi ed. Cultural remains found in the coastal exposure and in the stratigraphic section belong to the Early and Middle Paleolithic. The early stage in the peopling of the Northeastern Azov and the Lower Don regions is documented by Early Paleolithic artifacts found in the subaqueous deposits of layers 5 and 6 (MIS 9–11, ~420– 270 ka BP). Heavil y waterworn patinated lithics include a core-shaped artifact, variou s types of side-scrapers, a scaled piece, fl akes, and chips. This complex is an informative addition to known complexes from the region, including contemporaneous ones. The most interesting is the Middle Paleolithic industry of layer 4 under the Kamenka (?) soil— layer 3, MIS 7. The toolkit consists of a diagonal side-scraper and a chip found in the section, as well as radial and Levallois cores, various side-scrapers, a par tly bifacial tool, spalls , and chips found in the denudation. Technological and typological criteria (primarily the Levallois technology) and the tentative date of non-waterworn patinated lithics make it possible to attribute them to the Early Middle Paleolithic of the southern Russian Plain. It is concluded that cultural remains of the Early Middle Paleolithic, dating to ~243–191 ka BP, have been found in the region for the fi rst time, fi lling the gap in the local Early Middle Paleolithic sequence. In adjacent regions, similar industries have been known since the late 1900s.

The results of morphometric analysis based on the SRTM digital elevation model of large enclosed depressions (LEDs) of controversial origin, commonly found on the loess interfluves in the Northern Black Sea region, around the Sea of Azov, at the Western flanks of Caucus Mountains and in the Lower Don basin, are presented in the paper. We have registered 312 LEDs landforms. The morphometric characteristics of landforms vary from 0.4 to 216 km2 for area, from 1 to 21 m for depth, from 0.5 to 13.3 km for width, from 0.7 to 27.5 km for length, from 1 to 4 for elongation coefficient, and from 3.3 to 103.3 m a.s.l for height. The most common depressions have the following parameters: area 24 km2; depth 23 m; width 1.01.5 km; length 2.53.0 km; elongation coefficient 1.21.4; height 1520 m a.s.l. There is a correlation between the area and depth of the depressions. The depressions' shape is mostly elongated, e. g. teardrop-shaped, eggshaped, elliptical, triangular, and rarely round. The sharp ends of the egg-shaped depressions always tend to point to the north, and the blunt ones to the south. We grouped the depressions into seven restricted sites where the differences in size and other morphological features of the LEDs are very small. Within all sites, there is a high consistency of orientation of the long axes of the depressions. The largest depressions around the Sea of Azov and the Western flanks of Caucus Mountains are characterized by longitudinal ridges confined to western side of LEDs. Comparison analysis of sites demonstrated a fan-shaped pattern in changing of the long axes orientation from the NW in the Northern Black Sea region; to the East in the Azov Sea region; to the N in the Western flanks of Caucus Mountains; and the NE in the Central flanks of Caucus Mountains. A radial-centripetal pattern of the erosion network is observed across the territories where LEDs are distributed. Small erosive forms flowing into the center of depressions are represented by very flat and wide gullies and hollows with intermitted channel flow. Such morphological characteristics suggest the relict origin of the erosional forms and, as a result, indicates the pre-Holocene age of the depressions themselves. Morphological and geological data suggests that wind erosion was probably the main factor in the formation of LEDs.

The paleoclimatic reconstruction of the last 14 ka was carried out by GPR sounding, spore–pollen analysis, and radiocarbon dating of a peat section (7 m) located in the model bog of Valdai National Park (Novgorod oblast). The peat accumulation rates varied from 0.075 mm/yr during the Late Glacial to 0.15–1.15 mm/yr during the Boreal stage (when the level of the Valdai lakes dropped by 10 m) and up to 4.25 mm/yr in recent centuries. Numerous cycles of the Holocene warming/cooling events were within ±1–2°C compared to the current ones and were accompanied by moderate fluctuations in annual precipitation (±25–50 mm). The forest composition changes were the most considerable during the Atlantic period, when spruce–broad-leaved forests and oak woods were predominant. Over the last two thousand years, the regional vegetation dynamics has mainly been influenced by agricultural activity.

The paleohydrological condition in the Rostov depression (Yaroslavl region) has been the subject of many years of discussions. The ideas about the Holocene fluctuations of the Lake Nero level differ among researchers. We have studied the structure of bottom sediments and bottom topography in the deepest northeastern part of the lake. A bathymetric survey was carried out. Drilling with the selection of undisturbed columns, GPR profiling, radiocarbon dating and a set of lithological analyzes were performed. Stratigraphic unconformities in the structure of bottom sediments indicate a drop in the lake level during the Lateglacial and the early Holocene. The level dropped to 87 m asl, which is 7 m lower than the current water level in the lake. The size of the lake at this stage was reduced several times. From 9 to 6.5 ka BP a transgressive stage was established: the average level of the lake could have risen to 91–94 m asl, which is close to its modern level. From 6.5 to 2.4 ka BP a decrease in the level by 1–3 m below the current one is revealed, followed by a gradual increase in the level. The current level was reached 300–500 years ago. The main factor in the fluctuations in the level of Lake Nero in the Holocene is the change in the height of the runoff threshold, caused by the transformation of the Ustye, Veksa, and Kotorosl river sistems. This transformation was associated both with regional changes in fluvial activity and with the processes of self-development of river channels.

The article discusses the first results of studying the structure of the bottom topography and bottom sediments of Chukhlomskoe Lake (Kostroma Region, Chukhlomsky District). We analyzed the lake bottom topography based on the results of our bathymetric survey and discovered two hollows with maximum depths diverging from the lake’s center towards the city of Chukhloma. The maximum depth inside the hollows (and for the entire lake) reaches 5.4 m, and the average lake depth is 2.2 m. There are two steps seen in the bottom topography; 2.0–2.4 m and 1.5–1.8 m. The bottom sediment structure of Chukhlomskoe Lake was revealed by drilling from the ice with two boreholes (with lengths of 9.45 and 7.45 m, located in the area of background depths and inside the hollow, respectively). Five radiocarbon AMS dates were obtained for the core from the hollow’s bottom. The sedimentary sequences of the pre-Holocene part of both cores show high similarity in structure and depths of the marker horizons identified by a set of lithological analyses. The structure and thickness of Holocene sediments differ significantly. In the area of background depths, the Holocene organo-mineralogenic silt is 3.8 m, and inside the hollow, the thickness of this layer is only 1.45 m. Moreover, hiatuses in sedimentation were documented in the structure of the Holocene sediment inside the hollow. The age of hiatuses, based on the sedimentary model, was estimated as 10.6–5.3 and 4.9–0.06 thousand years ago. A probable mechanism for the origin of hollows is localized erosion caused by wind currents in a highly shallow lake. An additional erosion factor can be the degassing of bottom sediments, which leads to the loosening of the bottom layer of sediments, which makes them susceptible to erosion. The cutoff of sediment erosion inside the hollow coincided in time with the construction of a dam on the Veksa River and a rise in the lake level by 1.0–1.5 m in the 1960s.