From the geological point of view, the White Sea is one the best studied basins. The first schemes of its evolution were put forward by I.K. Avilov based on the data obtained before 1950, and by M.A. Lavrova based on the results of studying coastal outcrops on the Kola and Onega peninsulas and in Karelia. Research activities of the Institute of Oceanology, Academy of Sciences of the USSR, in the White Sea in 1964–1968 under the leadership of E.N. Nevesskii made it possible to present the first lithostratigraphic scheme of its Quaternary sequence and to distinguish the following stages in its evolution: glacial, glacial-marine, transitional, and marine. The onset of the first periglacial basins dates back to the Middle Dryas, while the glacier with surrounding ice shelves occupied a significant part of the White Sea basin. Besides extensive geological sampling, research activities of VSEGEI and Moscow State University in 1970–1986 included seismoacoustic profilingand side scan sonar survey, which were for the first time applied for the shelf geological survey. New data on the distribution of varved glaciolacustrine beds gave evidence for the initiation of water basin in the White Sea depression, which was later filled with the Barents Sea waters since the Allerød until the Boreal. Further studies (MAGE, Sevmorgeo, IO RAS, VSEGEI) made it possible to obtain fundamentally new geological and geophysical materials and to build geological maps at a scale of 1 : 1000000 for the entire seabed of the White Sea. These research activities included specific biostratigraphic studies and dating of the Quaternary sediment sequences. Specialists from KSC RAS, Institute of Lacustrine Research RAS, Moscow State University, Herzen Russian State Pedagogical University, and Institute of Geography RAS carried out coastal research that included drilling of lakes recently isolated from the sea. The latter made it possible to clarify the age and number of Postglacial transgressive-regressive cycles of the White Sea and to establish the limits of marine basins on land. Also, the peculiarities of neotectonic processes on the Kola Peninsula and their influence on the development of underwater gravity processes are highlighted.

In the course of fieldwork in 2019–2021 on the southern coast of the White Sea, the authors of the article collected representative material for tectonophysical research—measurements of spatial orientation of geological stress indicators: sliding mirrors, separation, veins and fractures. To analyze the collected material, a complex of tectonophysical methods was applied, namely, the method of cataclastic analysis of discontinuous displacements, the structural-paragenetic method, the structural-geomorphological method and the SimSGM program, fracture analysis. Data on the stress state throughout the Kuzokotsky Archipelago and the adjacent territories of the Great Salma Strait were obtained. By the method of cataclastic analysis, 10 local stress states were obtained, 11 by the structural-paragenetic method, and 10 by the structural–geomorphological method. On the territory of the Kindo Peninsula, Veliky Island, and the Kuzokotsky Archipelago, local stress states of different ages have been reconstructed, which were tied to the tectonic history of the Kandalaksha graben. Variations of stress-strain states for different sites are revealed. And a hypothetical model of the gradual evolution from the north-west compression to the north-east during the latest tectonic stage is proposed. Local stress conditions confirm the presence of transtension conditions in the axial part of the rift structures of the Great Salma Strait. The identification of voltage sources made it possible to update the history of the development of the Kandalaksha graben. According to the expanded database of fracturing and other geological stress indicators, it will be possible to reach regional geodynamic regimes, which in turn is useful for predicting earthquakes.

The article presents the main results on the stratigraphy and geochronology of Quaternary sediments, as well as data on neotectonics, seismicity and the movement of the coastline of the White Sea obtained in recent decades by geological-geomorphological, biostratigraphic, paleoseismological methods, numerical dating methods and allowing us to present a paleogeographical model of the Kola-Karelian region. The lack of one for the White Sea coastal area located within the Fennoscandian Shield caused the relevance of the presented synthesis. Interglacial marine and glacial deposits of the Middle and Late Pleistocene and Holocene were identified. Only the sediments of the Last Glacier and its meltwater, as well as Postglacial marine and aeolian deposits in some places, are of landform-forming importance. During the last glaciation, the marine regime in the White Sea basin was interrupted. Extensive freshwater lakes appeared in the White Sea basin due to glacial meltwaters during the deglaciation. These proglacial lakes became brackish-water in the Allerod as Atlantic waters entered. In contrast to earlier study, only two marine transgressions have been identified here, which took place at the Late Glacial–onset of the Holocene and at the late Early Holocene–early Middle Holocene. The Kandalakshsky and Tersky Coasts of the White Sea are characterized throughout the Holocene by a different-amplitude glacioisostatic and tectonic uplift, especially active in the western part of the Kandalakshsky Coast. Within the Karelian Coast, in the last 4000 years tectonic block, rather than domeshaped glacioisostatic uplift of the Earth’s crust prevails. Due to the glacial rebound, strong earthquakes occurred on the coasts of the White Sea, which were manifested by visible deformations of the continuity of rocks and deposits. In the eastern Fennoscandian Shield, the most tectonically active part is the coastal areas of the Kandalaksha Bay. The stress and relaxation of the Earth’s crust during the Last Glaciations, along with the tectonic movements, provoked the migration of the coastal line, differing in its rates in different parts of the White Sea depression.

We present a composite section of the Upper Quaternary sediment beds and preliminary reconstructions of the Late Pleistocene sedimentation environments in the southeastern White Sea Region, obtained as a result of field and analytical research on the coast of the Kuloi Plateau, generalization of published evidence and geological survey reports, together with correlation of existing continental and marine palaeoarchives. The studies included lithostratigraphic descriptions of sediment sections, linking lithological boundaries to the absolute heights, diatom and malacofaunistic analyses, and OSL dating of deposits. Until now, many questions of the Late Pleistocene history of the region remained open: the age and amplitude of marine transgressions, the boundary and the very fact of the penetration of the Early Valdai glaciation into the territory of the Kuloi Plateau, the eastern boundary of the last glaciation and the distribution of glacial, glaciofluvial, glaciomarine and marine deposits accumulated during the period of its degradation. On the basis of the obtained data, preliminary conclusions were made concerning the relationship between glacial and marine paleoenvironments in the southeastern White Sea Region in the Late Quaternary. Apparently, marine sedimentation environments prevailed during almost the entire Late Pleistocene (except for MIS 2). The multiplicity of the local early Valdai glaciations is still doubtful and does not correspond to the obtained lithological and geochronometric data. The most complete Late Quaternary sediment sequences are exposed in the outcrops on Zimnii Coast. On Abramovskii Coast, the number of sediment beds decreases, here deposits of the maximum stage of the last glaciation overlie clays and sands of the Mezen’ transgression. It can be assumed that Abramovskii Coast, in contrast to Zimnii Coast, undergoes less amplitude and rates of glacioisostatic uplift.

Paleolimnological studies have been performed at 9 lakes at the Anzer Island (Solovetsky Islands, the White Sea). Changes in lithostratigraphy and organic matter content in the sediment sequences reflect changes in sedimentation environments related to the isolation from larger basins. Based on the Holocene dynamics of organic matter content, three periods of the organic accumulation were distinguished in the lakes located below 22 m a.s.l. corresponding to the main stages of the lakes’ evolution. At the earliest stage, lake basin was incorporated into a larger basin (glaciolacustrine or marine), and the lowest organic matter content is characteristic for its sediments. At the isolation stage, laminated sediments form, and organic matter content rapidly increases. At the isolated-lake stage, organic-rich sediments are accumulated. The calculated rate of the lacustrine (gyttja) sedimentation is ca. 0.2–0.3 mm year–1. Organic sedimentation in the lakes located at 22– 35 m a.s.l. at Solovetsky Islands have been taking place since 10500–11000 cal. years BP. The age of the lakes’ isolation was found to correlate to their elevation above sea level. Based on the time of the isolation and the onset of the lacustrine sedimentation, the shoreline displacement curve for the Anzer Island was constructed for the second half of the Holocene. Ca. 4800–4400 cal. years BP, the relative sea level was below 11 m a.s.l., while ca. 1900–1700 cal. years BP the shoreline regressed below 2 m a.s.l. The calculated rate of the shoreline retreat is ca. 2–3 mm year-1. The Holocene marine limit at the Solovetsky Islands was corrected, and established at 17–21 m a.s.l.

diatom analysis and radiocarbon dating of samples of bottom sediments of Lake Konyukhovskoye (64.882° N, 36.586° E) with a hypsometric level 15.8 m and a runoff threshold of 17.0 m a.s.l. are presented. The results of the analysis of bottom sediments allowed reconstructing the history of the lake and changes in the level of the White Sea in the Holocene. For the first time, Lake Konyukhovskoye was isolated during the Early Holocene regression earlier than 10.2 thousand cal. years BP. Sea conditions and the connection with the White Sea arise during the Tapes transgression ~9.0–8.8 thousand cal. years BP. The relative sea level during the maximum of the transgression was ~17.5 m a.s.l. The final separation of Lake Konyukhovskoye occurred as a result of a drop in sea level below 17.0 m earlier 6.9–6.8 thousand. cal. years BP.

Dry cover peatlands have been investigated on 11 islands of the Kandalaksha Bay in the White Sea. The peatlands occupy the central convex parts of islands or some of their capes and gentle slopes up to 5° following the mineral surface of the island. Their modern vegetation is represented by xeromorphic Empetrum heaths. Peatlands develop directly on rocky surfaces, as well as on sand and pebbles that overlap them. The peat formation on the island surfaces begins as they go beyond the supralitoral zone due to the land uplift continued at the present time. The peat deposit thickness, on average, is about 30 cm, reaching a maximum of 71 cm. Botanical macrofossil analysis of peat showed that peat accumulation begins both at the stage of coastal meadows and at the stage of Empetrum heaths. The main peat forming plants are crowberries, blueberries, cloudberries, green mosses and some other species present in modern xeromorphic communities. Accordingly radiocarbon dating of the bottom layers of peat, the vertical uplift rate of the islands’ surface is relatively uniform and is estimated at 4 (to 5) mm per year, which corresponds to the uplift rate of the mainland coasts of the bay. The measured radiocarbon age of peatlands ranges from 425 to 1840 years, the estimated age is up to 2760 years. The peat accumulation rate is relatively constant throughout the existence of peatlands and is estimated, on average, at 0.14–0.15 mm per year. The study disproof the previously made assumption about the relict nature of Empetrum heath peatlands.

We studied three cores of peat bogs in the interfluve of the Varzuga and Strelna rivers and the depression of Sergozero Lake with palynological method. Thus allows us an assessment of characteristics of the main stages of vegetation development during the Holocene and Post Glacial time. An assumption has been made about the Preboreal age of the limnoalluvial strata in the interfluve of Varzuga and Strelna, which covers on the sediments of the Last Glacial till. Two radiocarbon dates were obtained, the beginning of peat accumulation in the studied area is dated. The bottom part of peat exposed in slope of the Sergozero Lake terrace dated to 11645–11589 cal. BP. At the same time, pine forests developed in the surrounding area. Peat accumulation reached its maximum development in the Atlantic period. At that time, spruce-pine communities with boreal flora elements dominated the territory. In the pollen spectra correlated to Subboreal time, the thermophilic flora disappears. For the correct interpretation of the results of palynological analysis, subrecent surface samples were taken. Their spectra show a high degree of correlation with each other, reflecting the existence of modern pine communities in the studied area.

In the 1930s, a scientific group from the White Sea Methodological Station of the State Hydrological Institute studied in detail a relict reservoir in the eastern part of the Porya Bay under the local name “Ozerki.” It consists of three reaches, one is connected to the sea at high tide, the next is connected with the first through a narrow shallow strait, and the last, apex reach communicates with the middle one. A re-examination almost 90 years later showed that due to the ongoing post-glacial uplift of the coast, the thresholds separating the “Ozerki” from the sea became shallower. With the help of pressure loggers, it has been established that the tide in the lagoon now begins at a sea level 20–30 cm higher than in the 1930s. As a result of progressive isolation, a stable vertical stratification has developed in the apex reach indicating possible meromoxis, and an anoxic zone with a high hydrogen sulfide concentration has appeared, which occupies a third of the depth of the reservoir; the concentration of mineral phosphorus increased by two orders of magnitude. In the reaches, an increase in the total abundance of zooplankton is traced with distance from the sea, an additional ecological niche appears—a chemocline, in which marine rotifers dominate in the early stages of isolation, and polychaete larvae from the order Spionidae dominate after the formation of a permanent hydrogen sulfide zone.

For the first time the taxonomic composition and vertical structure of phototrophic protist (PhP) communities were determined in a meromictic water body of the Russian coast of the Arctic, namely a lagoon Lake Kislo-Sladkoe, using DNA metabarcoding. Temperature, salinity, oxygen concentration, pH, Eh, illumination, and functional parameters of chlorophyll fluorescence were measured at different depths. 140 operational taxonomic units of PhP belonging to major taxa Dinoflagellata, Chlorophyta, Cryptophyta, Haptophyta, Ochrophyta, Cercozoa were identified. PP predominated over heterotrophic protists at depths of 0– 1.0 and 2.5–3.5 m reaching a maximum in the chemocline, especially in the 3.0 m horizon, above the redox transition. The taxonomic composition of the PhP in different layers differed according to the hydrological and hydrochemical stratification. In addition to abiotic factors, the composition and distribution of PP was influenced by predatory protists such as the cercozoan flagellate Ebria tripartita and the dinoflagellate Oxyrrhis marina, which significantly reduced the abundance of PhP while their mass distribution. Five layers were identified with different sets of dominant PhP. The surface 0−0.5 m layer of freshened water was featured the dominance of cryptophytes Teleaulax sp. and Hemiselmis cryptochromatica. The photosynthesis activity here was lower compared to the underlying layers that may be determined by photoinhibition. In the 1.0–2.0 m layer of seawater below the pycnocline Chlorophyta dominated, which are typical for picoplankton of the northern seas, as well as representatives of Cryptophyta, Haptophyta, Pedinellida, and diatoms. The PhP community at the lower boundary of the oxycline (2.5 m) had a specific structure with the mass development of the mixotrophic dinoflagellate Heterocapsa rotundata, for which the most favorable conditions were formed here facilitating the transition from photosynthesis to phagotrophic consumption of bacteria. In the chemocline, a maximum of chlorophyll was recorded, which was formed by cryptophyte Rhodomonas sp., demonstrating high rates of photosynthesis efficiency, despite the presence of hydrogen sulfide and low illumination. In the deeper anaerobic zone, cysts and DNA of dead protists were preserved apparently, whereas the remains of the protist cells settled in the bottom layer.

The hydrological and geomorphological processes occurring in the macrotidal Mezen and Kuloy estuaries are completely subject to the effects of the tidal wave. The main purpose of studying the dynamics of suspended matter and sedimentation processes is to determine the river and marine factors affecting sediment transport and the features of lithodynamic processes. Expeditionary studies of the Mezen and Kuloy estuaries, which were conducted by the author in 2005−2019s, showed that a high concentration of suspended sediments compared to the adjacent areas of the river and sea is observed in areas of reversible currents. The concentration of sediments was determined by weighting of the filtered samples taken during the tidal cycle, while simultaneously recording the hydraulic parameters of the water flow. The maximum value of spring tides in the of Mezen estuary reaches 9.8 m, in the neap tides—5.0 m; in the Kuloy estuary during of the spring tides is 10 m, in the neap tides—4.8 m. Tidal velocities during of the spring tides reach 2.5 m/s. The salinity of water in the estuaries of Mezen and Kuloy varies from 3.5 to 24.0 ups. The greatest values of turbidity are noted in the lower part of the estuaries during the low water and in the top of the studied estuaries in the high water. The maximum turbidity in the Mezen estuary reaches 56.3 kg/m³ during the low water due to the concentration of suspended sediments in the bottom horizon. In the surface horizon, even with a change in the direction of the flow and during the period of slack water, fine clay particles are not deposited to the bottom, but are in suspension. The turbidity of water in the surface horizon is stored in the range of 0.05–0.10 kg/m³. The increase in turbidity is facilitated by wind wave on the offshore and intense abrasion of the banks in the estuaries. The conditions for the economic use of the mouths of the Mezen and Kuloy rivers depend on the tides. Navigation can be carried out only during the period of high water, and requires taking into account the dynamics of the fairway. When designing the Mezen tidal power plant, it is important to know the areas of greatest sedimentation in the open and separate parts of the tidal basin.

Marine sedimentation was studied using dispersed sedimentary material of the water column in sediment traps in comparison with the surface layer of bottom sediments. Based on the generalization of long-term studies of a small inland sea of the Arctic Ocean, it was possible to establish new regularities of the sedimentary process in the conditions of the Subarctic and Arctic zones. The quantitative transition of dispersed forms of sedimentary matter into concentrated forms (bottom sediments) in the White Sea fluxes a linear relationship, with a local maximum in the deep nepheloid layer. Areas of ultrafast sedimentation are distinguished— marginal filters (Northern Dvina River). Direct quantitative data on the fluxes of sedimentary matter in the water column of the White Sea, obtained using sediment traps at the ADOS observatories over 15 years of research, gave the following values: under the active layer in the range of 48–214 with an average of 74 g/m²/year; in the intermediate layer 54–298 with an average of 132 g/m²/year; in the near-bottom horizon 149–1814 with an average of 335 g/m²/year. The sedimentation rates (for ²¹⁰Pb, ¹³⁷Cs) of the surface layer of bottom sediments in terms of the mass accumulation rate (MAR) of dry sediment correspond to the interval 93–1260 with an average of 310 g/m²/year. Long-term data on the concentration of suspended matter and the flux of dispersed sedimentary matter clearly record stable year-round nepheloid layers, i.e. the distribution of scattered forms of sedimentary matter (suspension) in the water column occurs according to new patterns, which can be more clearly identified.

One of the topical issues in studying the adaptation of the ancient population to the natural conditions of the White Sea is to identify the features of the development of the shores of the Kandalaksha Bay by primitive hunters, where, due to the constant movement of the coastline, a process of transformation of part of the sea bays into freshwater reservoirs is observed. The data published in this article were obtained by studying the topography, altitudinal location and chronology of the ancient settlements in the study region and comparing them with the rates of glacioisostatic uplift established in the last two decades for the western coast of the White Sea. In the course of the analysis of the materials of the archaeological sites explored on Nizhnee Nilmozero Lake, data were obtained on the presence in this microregion of a large group of Chalcolithic sites that existed here for a relatively short period (second–third quarter of the 3rd millennium BC), which, in turn, turn, allows us to clarify the time of formation of this large reservoir located in the northwestern part of the Kandalaksha Bay of the White Sea. The specifics of the topography of the Eneolithic sites on Nizhnee Nilmozero Lake indicate that they functioned under the continued influence of tidal fluctuations in sea level, at a time when this reservoir began to separate from the sea basin. The analysis of the bone remains allows us to conclude that the main occupation of the ancient population of Nizhnee Nilmozero Lake was hunting sea animals (seals). Fish bones were not found at the sites, so fishing probably did not play any significant role in the economy of the Chalcolithic population of Nizhnee Nilmozero Lake. The slate dart tips found at the Eneolithic sites of Nizhnee Nilmozero Lake were probably used by ancient people for to hunt pinnipeds. The connections of the Chalcolithic population of the Northwestern White Sea region with the more southern regions are traced by the finds of fragments of chopping tools of the Russian-Karelian type, apparently from metatuff; and various flint tools, among which the most significant is a series of arrowheads.

According to the interpretation of satellite images and field observations, 15 large areas where anthropogenic activity intensifies aeolian morphogenesis were identified. The area of each site varies from 0.3 to 8.7 km² (~27 km² in total). The aeolian landforms developing under anthropogenic pressure have been studied in 3 key-areas: the Terskiy coast (mouth of the Varzuga River), Letniy coast (mouth of the Yarenga River) and Zimny coast (from the mouth of the Ruchyi River to Cape Intsy). Geomorphological and GPR profiling, aerial photography by drone aircraft, lithostratigraphic description of coastal deposits and radiocarbon dating of dead tree fragments were carried out. The response of aeolian processes to the anthropogenic load and its dependence on coastal dynamics and sediment balance in the coastal zone over the past hundreds of years were considered. Disturbances in the natural relief and vegetation increased the removal of sand from the coastal zone at coasts of all dynamic types. If the budget of sediments in the coastal zone is negative or balanced, then deflation increases on coastal terraces. If the budget of sediments is excessive, then aeolian accumulation is increased. In the area of Kuzomen Village (the mouth of the Varzuga River), where the degradation of the natural relief is most significant, the directions of wind-sand flows have changed; the mass movement of sands begins at wind speeds lower than in undisturbed coastal areas. At least 20000 thousand m³ of sands were transferred towards the land in the areas affected by anthropogenic influence. The activation of aeolian morphogenesis at the mouths of the Yarenga and Varzuga rivers approximately coincides with the initial emergence of settlements (the middle of the 16th and the 17th centuries). The greatest changes in the coastal aeolian relief and processes are caused by the passage of vehicles and have occurred in recent decades.