STRUCTURAL-TECTONIC MODEL OF THE BASEMENT AND SEDIMENTARY COVER OF EAST ARCTIC WATER AREAS

Background. For a long time, deep deflections present in the Arctic basin seafloor have been a site for accumulating a thick sedimentary cover and a subsidence epicentre. Issues associated with the geological structure and tectonics of these formations have been addressed in numerous publications devoted to the East Arctic shelf.

Aim. To discuss the question of the geological and tectonic structure of Mesozoic-Cenozoic East Arctic water areas by analysing the existing geological and geophysical data on the Arctic shelf. Information on the structural evolution of the sedimentary basin is important from a practical point of view, since these areas contain a large number of extractable resources, in particular, hydrocarbon deposits.

Materials and methods. The present work reviews the results of exploration works using modern  technologies of basin analysis and numerical basin modelling. A structural-tectonic model of the East Arctic sedimentary basin was developed using the structural representations of the 1:5,000,000 scale performed by VSEGEI specialists in 2014. The developed model includes four main sedimentary complexes: pre-Aptian, Apt-Upper Cretaceous, Paleogene and Neogene-Quaternary. The modelling strategy was determined by the geological structure and evolution features of the sedimentary basin under study, as well as by the quality of available geological, geophysical and geochemical information. The East Arctic water areas were combined into a single model, since their sedimentary basins are part of the same continental margin and their boundaries do not always coincide with the conventional boundaries.

Results. On the basis of the conducted analysis of initial data, we developed a structural-tectonic model of the East Siberian and Chukchi Seas, as well as their surrounding areas. This model describes the  distribution of the main structural elements, their spatial relationships, as well as their regional hierarchical nomenclature. The developed model includes four main sedimentary complexes: pre-Aptian, Apt-Upper Cretaceous, Paleogene, and Neogene-Quaternary. The structural model covering the aquatic areas of the Laptev Sea, East Siberian and Chukchi Seas includes five main surfaces: the basement of the sedimentary cover; the Pre-Aptian unconformity; the Cenozoic base; the unconformity in the lower part of the Oligocene and the basement of the Quaternary sediments; as well as the modern bottom  topography.

Conclusion. Using the technology of basin modelling, a structural-tectonic model of the basement and sedimentary cover of East Arctic water areas was created, which can be used for planning exploration works.

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