The following research groups participate in the OSL Fellowship Program 2001.

1. Diel vertical migration of zooplankton in the Laptev Sea shelf waters
E. Abramova, D. Ivanova, I. Akhmetshina

2. Climate Changes and Sea Level Oscillations in the Laptev Sea Region in the Holocene as inferred from the data on the continental circumference (Taimyr Peninsula, Lena River delta, Severnaya Zemlya and New Siberian Islands Archipelagos)
D.Yu. Bolshiyanov, G. Fedorov, L. Savelieva

3. Thermal regime of the bottom water layer in the Laptev Sea in terms of submarine permafrost evolution
I. Dmitrenko, S.L. Berezovskaya, S.A. Kirillov

4. Acoustic pattern and physical properties of the top of submarine permafrost in the eastern Laptev Sea and their relationship to sea-bottom morphology and tectonic setting
S.S. Drachev, D.I. Chizhov, V. Kaulio

5. Hydrochemical structure in the Chukchi Sea in comparison to the Laptev Sea
E. Kirillova

6. Organic carbon isotope geochemistry in the Kara Sea as compared with the Laptev Sea
I.Yu. Mardanyan

7. Pollen in the Laptev Sea sediments as Holocene climate indicator
O. Naidina, Y.V. Kosenko, M.V. Tekleva

8. Nutrient fluxes into the East Siberian Sea in comparison to the Laptev Sea
E. Narkevsky

9. Balance model of the hydrochemical regime of the Laptev Sea
M.A. Nitishinsky

10. Quaternary biostratigraphy and paleoenvironmental reconstruction of the Laptev Sea shelf
Ye. Polyakova, O. Rudenko, T. Novichkova

11. Late Pleistocene development stage of the Laptev Sea continental margin
P.V. Rekant

12. Subsea periglacial processes in condition of recent thermal regime of the bottom water layer: Laptev Sea region, Russia
N.N. Romanovskii, A.L. Kholodov, V.E. Tumskoy

13. Last glacial environment and climate of the Laptev Sea shelf land
A.V. Sher, S.A. Kuzmina, T.V. Kuznetsova

14. Pathways and fluxes of natural and anthropogenic tracers in the Laptev Sea and adjacent Arctic Ocean
V. Shevchenko, A. Novigatsky, A. Klyuvitkin

15. Holocene transgression on the eastern Laptev Sea shelf: evidence from fossil assemblages and oxygen isotope studies
E.E. Taldenkova, A. Stepanova, S. Dem'yankov

16. The Bathymetry of the Laptev Sea continental margin and the main relief forms in the Late Cenozoic
A.V. Zayonchek, E.A. Gusev, A.A. Chernyh


1. Diel vertical migration of zooplankton in the Laptev Sea shelf waters

E. Abramova, D. Ivanova, I. Akhmetshina

Though daily vertical migrations of zooplankton caused by different factors, primarily light, have been long studied, they still remain largely unknown. There is no clear evidence about daily migrations of plankton in the polar seas. The published data on this item are scarce and rather contradictory. To study vertical distribution of planktic organisms, in August-September 2000 during the joint Russian-German expedition TRANSDRIFT VIII layer-by-layer zooplankton catches were carried out. ADCP and CTD records from bottom oceanographic stations were obtained. Analysis of vertical distribution of plankton based on layer-by-layer catches being correlated with analysis of ADCP data will give evidence for daily vertical migrations of zooplankton in polar seas. To understand mechanisms and peculiarities of daily vertical migrations during various seasons and, especially, polar day and polar night, the yearly ADCP records of bottom stations will be analyzed. The stations were deployed in the Laptev Sea from August 1998 till August 1999. In addition, the data on layer-by-layer zooplankton catches from previous expeditions (MERA-95, TRANSDRIFT V and VI) will be analyzed.

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2. Climate Changes and Sea Level Oscillations in the Laptev Sea Region in the Holocene as inferred from the data on the continental circumference (Taimyr Peninsula, Lena River delta, Severnaya Zemlya and New Siberian Islands Archipelagos)

D.Yu. Bolshiyanov, G. Fedorov, L. Savelieva

The aim of the project is to reconstruct climate oscillations and the levels of the basins in the Laptev Sea region during the Holocene and at the Late Pleistocene/Holocene boundary. Objectives: To carry out palynological, diatom, chemical, lithological and radiocarbon analyses of Quaternary deposits sampled during the joint Russian-German expeditions in 1993-2001. Generalize all available materials on the structure of the Holocene deposits of the land surrounding the Laptev Sea. Create a database of the results of spore-pollen and radiocarbon analyses of the Holocene and the Late Pleistocene deposits of the land surrounding the Laptev Sea. Construct the curves of summer air temperature and sea level oscillations for the different coast areas of the Laptev Sea region. Generalize all available materials in the form of maps of landscape zones for different time slices of the end of Late Pleistocene and Holocene. The results obtained using the methods developed along with new data are inconsistent with traditional understanding. The Holocene Climatic Optimum for the archipelagos of Severnaya Zemlya and the New Siberian Islands occurred about 10.5-9 kyr BP similar to the Putorana Plateau area. The most favorable climatic conditions in the territory of the Taimyr Peninsula formed 8.5-7.5 kyr BP. The last noticeable level rise in the Laptev and Kara seas (of 5-10 m) occurred between 1500 and 800 years BP. Therefore, to achieve the goals of the project it is necessary to continue addressing the problems of methodological character and update the geochronological scale based on the new results.

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3. Thermal regime of the bottom water layer in the Laptev Sea in terms of submarine permafrost evolution

I. Dmitrenko, S.L. Berezovskaya, S.A. Kirillov

The submarine permafrost is one of the most sensible components of the Arctic climatic system. Its stability strongly depends on the bottom temperature regime which still remains poorly studied. This project would aim at a determination of the influence of a certain amount of physical processes on the thermal regime of the bottom layer in the Laptev Sea in terms of submarine permafrost evolution. The sea currents regulating vertical fluxes of heat exert control over a number of important environmental processes, in particular, bottom thermal regime, bottom and coastal erosion, resuspension of bottom sediments. Acoustic Doppler current profiler observations carried out in the Laptev Sea in 1998-1999 within the frame of the Russian-German project "Laptev Sea System" for the first time revealed the turbulent rate of vertical exchange across the density interface and Atlantic warm water intrusions onto the shelf due to wind-forced bottom circulation. It should be noted that up to now these processes have not been taken into account for the bottom thermal regime. The study would focus on convective mixing, wind-forced and thermohaline circulation, solar radiation, fresh warm water input via river runoff as critical processes controlling the thermal condition of bottom water and evolution of submarine permafrost. Based on the analysis of the very extensive hydrographic data set from 1960 up to 2000 and unique acoustic Doppler current profiler records by statistical and thermodynamic methods vertical and horizontal fluxes of heat through the density interface will be calculated for the annual cycle. For further understanding of the relationships between these fluxes and the Laptev Sea submarine permafrost these data will be analyzed in conjunction with the general atmospheric circulation over the Arctic Ocean, multiannual average hydrography, suspended matter records as well as regional meteorological information. Owing to the importance of the bottom layer thermal regime for a wide variety of coastal processes, the study could provide important baseline information to the Laptev Sea System project and at the same time help extend our understanding of the impact of bottom hydrography on the environmental interactions in the Laptev Sea.

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4. Acoustic pattern and physical properties of the top of submarine permafrost in the eastern Laptev Sea and their relationship to sea-bottom morphology and tectonic setting

S.S. Drachev, D.I. Chizhov, V. Kaulio

The submarine permafrost (SMP) in the Laptev Sea was initially discovered in the 1970s by shallow exploration drilling around the New Siberian Islands, and then was numerically modeled and, finally, verified in 2000 by drilling in the northeastern part of the shelf under implementation of the TRANSDRIFT VIII expedition. 42 m of sedimentary cores in all were recovered from 5 holes at 3 sites by the Russian drilling vessel KIMBERLIT. The cores show the top of SMP of both ice-bearing and ice-bonded types to occur at only 9 to 12 m below the seafloor. Revealing the different characteristic facies of the uppermost part of the SMP developed in the eastern Laptev Sea, how they are reflected in the acoustic record and, where available, physical properties, constitutes the main goal of the proposal. The following analysis of possible relationships between these acoustic facies of the upper SMP with seafloor morphology and structural elements of the active rift system represents a subordinate task. The complete set of the PARASOUND profiles recorded during RV Polarstern ARK-IX/4 (1993), ARK-XI/1 (1995) and ARK-XIV/b (1998) missions into the Laptev Sea and the drill cores recovered in the year 2000 constitute the basic data set, which is fully available for the research team. These results of the proposal implementation will be of significance for the scientists engaged in the Arctic environmental studies and particularly for further investigations of the SMP in the Laptev Sea.

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5. Hydrochemical structure in the Chukchi Sea in comparison to the Laptev Sea

E. Kirillova

The proposed research constitutes a study of the hydrochemical structure of the Chukchi Sea in comparison to the Laptev Sea. The Chukchi Sea occupies the extreme eastern portion on the huge Siberian shelf. The high nutrient inflow with Pacific waters entering through the Bering Strait greatly influence the processes in the Chukchi Sea. The Chukchi Sea is one of the most productive seas on the Arctic Shelf. The Laptev Sea is strongly influenced by an immense riverine inflow of freshwater. Its topography, oceanography and ice dynamics differ considerably from that of the Chukchi Sea. The Lena River discharges its enormous load of sediment and organic carbon onto the Laptev Sea shelf. Thus the Chukchi and Laptev seas are complex, different systems. The water column structures of the seas form under the influence of different physical, chemical, and biological conditions. But there are some common features, which are determined by their location at a high latitude, severe climatic conditions, and almost permanent ice cover. The main aims are to investigate the hydrochemical structure of the Chukchi Sea and to determine the main differences between the water column structure of the Chukchi and Laptev seas. The proposed studies will be based upon the high quality data set obtained during the unique TRANSDRIFT expeditions and AARI's archive data set. The work will be done as a part of the PhD thesis, which is planned to be finished next year.

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6. Organic carbon isotope geochemistry in the Kara Sea as compared with the Laptev Sea

I.Yu. Mardanyan

The proposed project is devoted to the investigation of the geochemical environment and diagenetic processes in sediments, which do not properly belong to the local characteristic of the Kara Sea. Some of them, for example those related to authigenic minerals precipitation and the methane cycle, are typical of the low-temperature polar areas, arctic shelf seas and the Laptev Sea in particular. Our experimental approach in the present study consists of organic carbon isotope analysis of sediments and particulate load coupled with a study of the stable isotope ratios in dissolved inorganic carbon (DIC) as a carbon source for primary bioproducers. Pyrolytic express technique will be used to get independent evidence for the genesis and source of organic matter. Stable carbon isotope analysis enables us to investigate the main elements of the carbon biogeochemical cycle in sediments by using the unified technique. Sedimentary organic matter, particulate material of sea ice and sea water, organic carbon of primary producers (phytoplankton), hydrocarbon gases (methane and its higher homologues), dissolved inorganic carbon as a photosynthesis substrate, organic and inorganic carbon of different carbonate inclusions in sediments – all these are the objects of our investigation. The natural conditions in the Laptev and Kara seas are very similar. There is a large river discharge with a huge volume of freshwater and terrestrial load being delivered to both seas, a high level of ice production, low temperatures – they all contribute to the common character of geochemical processes. There exists a similarity in geology and palaeoenvironment at the Holocene-Pleistocene boundary in the eastern Kara and Laptev seas. The similarity of the water body structure in both seas enables us to carry out a comparative study and to make evident special features for each of them in distribution pattern, composition and sources of sedimentary organic matter and particulate organic matter, and to elucidate the role of phytoplankton communities in the organic carbon pool in the basins under consideration. Taking into account that the advective transport of the Kara Sea waters eastward and northeastward is considered to be a pronounced source of sedimentary material to the Laptev Sea, it is felt that the system investigations in the Kara Sea might be important to get a more penetrating insight into the geochemistry and palaeoenvironment of the Laptev Sea.

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7. Pollen in the Laptev Sea sediments as Holocene climate indicator

O. Naidina, Y.V. Kosenko, M.V. Tekleva

In connection with the Russian-German investigation of the Siberian Arctic environment and its present and past role in global climatic changes a detailed pollen analysis of Laptev Sea shelf sediments is proposed. For the first time a high-resolution record of marine sediment sequence from the Laptev shelf area is analyzed by palynological means in order to investigate the relationship between past climate changes in the high Arctic on the basis of the dynamics in vegetation and marine-fluvial depositional environment. As our studies within the framework of the Russian-German project "Laptev Sea System" have shown, in suitable sedimentary setting pollen records from near-coastal marine sediments can give reliable information on climate-related vegetational changes on land. We propose to study the temporal link age between high-Arctic vegetational dynamics and shelf sedimentation processes. The study will focus on the western and the northeastern Laptev Sea – on sediment samples of radiocarbon-dated cores, collected during the Russian-German expeditions. The proposed research will focus on the investigation of pollen as indicators of source areas and climatostratigraphic interpretation of palynological data. The microsporogenesis of arboreal plants is influenced by Arctic climatic conditions. Therefore we intend to carry out the study of the sporoderm and protoplast of pollen indicators using electron microscopy (SEM, TEM).

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8. Nutrient fluxes into the East Siberian Sea in comparison to the Laptev Sea

E. Narkevsky

The proposed research consists of a study of nutrients distribution and variability in the Laptev Sea and the East Siberian Sea. The aim of investigation is to study the nutrient fluxes into the East Siberian Sea and determine the dominant mechanisms of nutrient exchange between the East Siberian Sea and the Laptev Sea. The East Siberian Sea is an open sea; it is the most shallow, the most sunny and most ice-covered sea, and is located on the huge Arctic shelf. It is separated from the Chukchi Sea by Wrangel Island in the east and from the Laptev Sea by the New Siberian Islands in the west. The East Siberian Sea is the less known sea among the seas of the Arctic region due to its remoteness and heavy climate conditions. Phosphate, nitrate, ammonium, and silicate are the mineral basis of primary production in seawater. The distribution of hydrochemical characteristics is determined by water mass circulation, vertical mixing and biogeochemical processes.

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9. Balance model of the hydrochemical regime of the Laptev Sea

M.A. Nitishinsky

In carrying out the project it is planned to finish the preparation of the PhD thesis. The main focus will be made on the studies of the hydrochemical regime and processes occurring in the Laptev Sea marine ecosystems. It is expected to obtain the mean annual nutrients distribution in the Laptev Sea, their seasonal and annual fluctuation, and to estimate nutrient fluxes on the sea shelf. For the realization of the project the following material will be used: the hydrochemical observations database including data collected in the Laptev Sea during the expeditions carried out by AARI and the joint German-Russian expeditions carried out within the framework of the "Laptev Sea System" project and the balance hydrochemical model of the Laptev Sea regime (Nitishinsky, 1999). As project result it is expected to generalize all available data on the Laptev Sea hydrochemical regime; to obtain nutrients fluxes and transformation estimation and their mean annual distribution within the sea maps creation. It is the first time that the Laptev Sea biochemical oxygen demand data will be analyzed.

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10. Quaternary biostratigraphy and paleoenvironmental reconstruction of the Laptev Sea shelf

Ye. Polyakova, O. Rudenko, T. Novichkova

The project is planned as a contribution to the multidisciplinary Russian-German Laptev Sea System Project for the joint study of the Quaternary sediments obtained during the TRANSDRIFT VIII expedition to the eastern Laptev Sea in 2000. The main goal of the proposed study is a detailed stratigraphic investigation of the Quaternary of the Laptev Sea and its paleoenvironmental reconstruction on the basis of microfossils in sediments from the Eastern Laptev Sea shelf. The proposed research activities will focus on the establishment of a Quaternary stratigraphy for the eastern Laptev Sea, reconstructions of the vegetational evolution in the Laptev Sea hinterland as linked to glacial-interglacial climate fluctuations in the Arctic. These investigations of Quaternary Laptev Sea sediments will help to solve a number of principal problems of paleoceanography and paleogeography of the Siberian Arctic.

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11. Late Pleistocene development stage of the Laptev Sea continental margin

P.V. Rekant

The proposed project presents the final stage of the author's work on the thesis on this topic. The work has been continued for the last 5 years and is based on the interpretation of available geophysical data on the area and their correlation with data of direct geological observations on the islands. It is possible at present to compare the accumulated geophysical material on the shelf of the area, continental slope and its foot with drilling data and direct geological observations on the mainland and the islands. In the course of the work it is planned to:- determine the main parameters of the sediment flux across the continental slope to the deep-sea basin and relate their change to the global ocean level oscillations.- perform regioning of the sedimentary mantle by the character of acoustic features and delineated areas with different types of a seismic-acoustic section.- relate the identified seismic-acoustic section features to the changed natural conditions in the course of sedimentary mantle accumulation. - reconstruct the character of natural conditions in the area during the Late Pleistocene-Holocene. The work will result in creating a set of maps and schemes characterizing the peculiarities of the region development for the last 75 kyr.

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12. Subsea periglacial processes in condition of recent thermal regime of the bottom water layer: Laptev Sea region, Russia

N.N. Romanovskii, A.L. Kholodov, V.E. Tumskoy

The Laptev Sea region is a unique cryosphere system with a very specific land-sea interaction. This proposal is directed at co-operative processing and using results of multidisciplinary investigation, especially new data about thermal regime of the bottom water layer in terms permafrost evolution. The aims of the project are: - to study the impact of the thermal regime of the bottom water layer on evolution of the upper part of offshore permafrost, on processes of subsea taliks re-freezing and subsea pingo formation for different regions of the shelf, - to estimate the seafloor thermoerosion rate; - to evaluate physical and chemical properties of terrestrial and marine deposits changing under influence of sea water and freshwater, respectively; - to make a prediction of the main subsea permafrost sections from the position of their modern state including temperature field, presence of ice-bonded, ice-bearing, cryotic and non-cryotic deposits, salinity of pore-ice and others. The project includes computer simulation, creation of new mathematical models and lab-investigation of deposits. The authors are planning to work in close co-operation with members of the project led by Dr. I. Dmitrenko.

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13. Last glacial environment and climate of the Laptev Sea shelf land

A.V. Sher, S.A. Kuzmina, T.V. Kuznetsova

New evidence on the Late Pleistocene geology, fauna and flora of the Laptev Sea Shelf Land, obtained in the course of the Russian-German cooperative research ("Laptev Sea System 2000" Program) and the current Otto Schmidt Laboratory project ("The LAPPAL Database"), provides a new insight into environment and climate of the East Siberian Arctic. A preliminary analysis of fossil insects, mammals, vegetation record and other paleontological and physical data invites a major revision of the existing concept of environmental history of unglaciated shelf land and adjacent areas during the LGM (Sartanian Glaciation, MIS 2) and the preceding "interstadial" (Karginian, MIS 3). The general climatic trend pronounced itself on this huge arctic territory in a very peculiar way. Our current hypothesis is that the special character of environmental changes on the shelf land resulted from interaction between the global climatic changes and extreme continentality of this land, combined with its position in the high Arctic. The proposed research can for the first time find a reasonable explanation for the flourishing of the fauna of herbivorous mammals in the high Arctic, which now seems so inhospitable for mammalian grazers. The project outlined in this proposal implies the analysis of the LAPPAL Database and development of a new concept of Last Glacial environment and climate of the Laptev Shelf Land by way of further study of fossil fauna and flora of the East Siberian Arctic. Testing our hypothesis and refinement of this concept will allow to understand how broadly it can be applied in this sector of the Arctic during the Last Glacial, and in the earlier Quaternary history.

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14. Pathways and fluxes of natural and anthropogenic tracers in the Laptev Sea and adjacent Arctic Ocean

V. Shevchenko, A. Novigatsky, A. Klyuvitkin

We would like to study the role of atmospherically derived elements and compounds, suspended matter, ice-rafted sediments, vertical particle fluxes in the processes taking place in the Laptev Sea and in the adjacent Arctic Ocean. This project is the continuation of the OSL 2000-2001 project "Atmospheric input of natural and anthropogenic tracers in the Laptev Sea and adjacent Arctic Ocean". We plan to do some new analyses of aerosol and suspended matter samples, collected during the ARK-XI/I expedition of the RV "Polarstern" (July-September 1995), to analyze aerosols and suspended matter collected during the 17th expedition of the RV "Akademik Fedorov", unpublished data on aerosol size distribution (ARK-XIV/la expeditions of the RV "Polarstern"), surface snow, water from melt ponds and ice-rafted sediments from the northern Laptev Sea and adjacent Arctic Ocean (expedition ARK-XIV/la of the RV "Polarstern"), sedimentary matter collected in the studied area by sediment traps during the ARK-XI/I and ARK-XIV/la expeditions of the RV "Polarstern" and the 17th expedition of the RV "Akademik Fedorov", soils, moss and lichens from the Russian Arctic hinterland. From the data of the Russian Center for Hydrometeorology we will be able to calculate trajectories of air masses. Analytical facilities of the Otto Schmidt Laboratory, P.P. Shirshov Institute of Oceanology and AWI-Bremerhaven could be used. It will be our contribution to the research program "Laptev Sea System 2000".

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15. Holocene transgression on the eastern Laptev Sea shelf: evidence from fossil assemblages and oxygen isotope studies

E.E. Taldenkova, A. Stepanova, S. Dem'yankov

The proposed research is a continuation of the currently running project "Detailed paleontological and paleoenvironmental studies on the Eastern Laptev Sea shelf" (OSL Fellowship 2000). Fossil molluscs, ostracods and benthic foraminifers were studied in two AMS14C-dated cores from the middle shelf area in the Lena (PS-51/138) and Yana (PS-51/135) paleovalleys. Such studies have never been performed earlier. Downcore succession of fossil assemblages revealed a definite change in depositional environment and bottom water properties caused by sea-level rise – from 1) near-deltaic environment with depths less than 10 m (around 11.1-11.3 cal.ka) to 2) transitional shallow-water environment with depths of 10-15 m 10.2-10.3 cal.ka and 3) abrupt change at 8.1-8.2 cal. ka to the onset of "polynya", i.e. normal marine conditions in this area. Recent molluscs, ostracods and foraminifers were studied in 18 surface samples from different parts of the sea, and general changes in their spatial distribution related to water depth, bottom relief, grounds, salinity and currents were revealed. During this year the research will be focused on fossil assemblage study on the inner shelf (core PS-51/092) and reconstruction of spatial changes in composition of fossil assemblages during different phases of post-glacial sea-level rise. Another focus is the study of oxygen isotope ratios in fossil and recent benthic ostracods and foraminifers along the Lena paleovalley to reconstruct temporal and spatial variations in river input. A combination of AMS14C stratigraphy, fossil assemblages and, if successful, d18O/16O variations will allow to reconstruct the Holocene paleoenvironmental history of the eastern Laptev Sea.

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16. The Bathymetry of the Laptev Sea continental margin and the main relief forms in the Late Cenozoic

A.V. Zayonchek, E.A. Gusev, A.A. Chernyh

Lately the Laptev Sea shelf has become an arena of intense scientific investigations. However there are no results based on all data available for this region. That is why one of the fundamental tasks of the "Laptev Sea System" project is the generalization of all available information and its compilation as a GIS dataset. The task is suggested to be solved based on bathymetry data interpretation that is the basis for geomorphology analysis and Quaternary geological study. All available data, collected during the last 10 years by Russian researchers and obtained during international expeditions, will be used for this purpose. The analysis of the geomorphology of the region combined with seismoacoustic and seismic data will allow to perform a retrospective morphostructural analysis to reconstruct the paleogeography of the Laptev Sea continental edge for the late Cenozoic. The main results will be a set of bathymetric, geomorphological, Quaternary deposits maps, paleoeographical schemes and transects. All the products will be created in GIS.

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