GRAIN-SIZE ANALYSIS OF BOTTOM SEDIMENTS FROM IVASHKINA LAGOON, BYKOVSKY PENINSULA
O.V. Levochkina1, V.E. Tumskoy2,3, O.V. Dudarev3,4
1Earth Cryosphere Institute, Tyumen Scientific Centre of Siberian Branch of the Russian Academy of Sciences, Tyumen, Russia
2Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russia
3Tomsk State University, Tomsk, Russia
4Il’ichev Pacific Oceanological Institute, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia
Keywords: thermokarst lagoons, Laptev Sea, lake sediments, lagoon sediments, sedimentological analysis, Passega diagram
Abstract
The results of sedimentological analysis of bottom sediments of the Ivashkina Lagoon on the southern coast of Bykovsky Peninsula (southeast of the Laptev Sea) are presented. Core samples from boreholes drilled in the Holocene thermokarst depression now occupied by the lagoon have been analyzed. The use of grain-size distribution data and Passega C-Md diagrams makes it possible to refine the genetic interpretation of the sediments obtained from field descriptions. The Holocene lacustrine-lagoon and taberal formations and the underlying Middle and Late Pleistocene alluvial sediments have been identified, and their grain-size characteristics have been determined. We have further reconstructed the sequence of their formation while a thermokarst depression had been transformed into a lagoon.
|
