Morphodynamics and Morphotectonics of the Mouth Area of the Varzuga River in the Late Glacial and Holocene (Terskii Coast of the White Sea)

Repkina, T.Y.; Zaretskaya, N.E.; Shvarev, S.V.; Lugovoy, N.N.; Alyautdinov, A.R.; Shilova, O.S.

Авторы: Repkina T.Y., Zaretskaya N.E., Shvarev S.V., Lugovoy N.N., Alyautdinov A.R., Shilova O.S.
Журнал: Doklady Earth Sciences
Том: 513
Номер: Suppl.1
Год издания: 2023
Издательство: Maik Nauka/Interperiodica Publishing
Местоположение издательства: Russian Federation
Первая страница: s24
Последняя страница: s46
DOI: 10.1134/S1028334X2360250X
Аннотация: Abstract—The late-glacial and post-glacial history of the development of the White Sea coastal zone in thearea of the mouth of the Varzuga River is considered as a result of the interaction of endogenous and exogenousfactors of coastal morpholithogenesis. Based on the field and office geomorphological investigations onthe study of Holocene deposits by lithostratigraphic, diatom, and radiocarbon analyses, as well as collectionand analysis of published data, new results on the development of relief for the area for ~13 cal ka BP havebeen obtained. The features of the regional hierarchical morphostructure and local post-glacial tectonics ofthe territory—the spatial relationships of blocks and the speed of vertical movements—were determined. Thesuperimposed linear Nizhnevarzugskaya Depression, which determined the configuration of the VarzugaRiver estuary in the late-glacial and post-glacial periods, was identified for the first time. The influence of thespatial ratio of blocks and differentiated post-glacial uplift on the coastal morpholithogenesis was established.The course of changes in the relative sea level (RSL), development conditions, and morphodynamics of theopen coast and the estuary of the Varzuga River were reconstructed, and new data on the rhythms of coastalmorpholithogenesis processes (coastal, estuarine, and eolian) were obtained. Three stages of development ofthe coastal zone were identified, which corresponded to regional rhythms of changes in the relative sea leveland climate. They are (I) the Late Glacial transgression and Early Holocene regression (~12 to 9.8 cal ka BP),(II) the Middle Holocene Tapes transgression (7.8 to 4.9 cal ka BP), and (III) the Late Holocene regression(after 4.9 cal ka BP). The upper marine boundary of the Late Glacial transgression was traced at heights of~54 or 55 m to the west of the Nizhnevarzugskaya depression, 39 or 40 m to its east, and 22 to 25 m a.s.l inthe depression. The shores of lower morphostructural blocks up to ~10.2–9.8 cal ka BP were probablyblocked by dead ice. During the Tapes transgression, the RSL reached a maximum (~20 m a.s.l.) of ~7.8 to7.6 cal ka BP and slowly decreased to ~15 m a.s.l. in the interval of ~7.6 to 4.9 cal ka BP. The prevailing directionsof sediment fluxes and the approaches of winds and waves became similar to those of today and havenot changed significantly since that time. The main source of the coastal sediment supply was the erosion ofglaciofluvial sediments and the input of sands from the seabed. In the interval of ~4.9 to 1.7 cal ka BP, theRSL decreased to ~5 m a.s.l. and then slowly approached the modern one. Activation of coastal (~5–1 cal ka BP)and channel (~4.9–4.7 to 3.6–3.4 cal ka BP) processes contributed to rapid filling of the estuary and formationof accumulative sand terraces on exposed banks. The sediment runoff of the Varzuga River became themain source of coastal sediment supply. After ~2.3 cal ka BP, several stages in the intensification of eolianprocesses were revealed.
Добавил в систему: Шварев Сергей Валентинович

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Morphodynamics and Morphotectonics of the Mouth Area of the Varzuga River in the Late Glacial and Holocene (Terskii Coast of the White Sea)статья

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