AGE, GENESIS, AND SEISMOGENIC DEFORMATIONS OF THE VUOKSA RIVER TERRACES ON THE KARELIAN ISTHMUS (northwestern Russia)
S.V. Shvarev1,2, D.A. Subetto3,4,5, N.E. Zaretskaya1,2,6, A.N. Molodkov7
1Institute of Geography, Russian Academy of Sciences, Staromonetnyi per. 29/4, Moscow, 119017, Russia
2Sсhmidt Institute of Physics of the Earth, Russian Academy of Sciences, ul. B. Gruzinskaya 10/1, Moscow, 123242, Russia
3Herzen State Pedagogical University of Russia, nab. Reki Moika 48, St. Petersburg, 191186, Russia
4Immanuel Kant Baltic Federal University, ul. Aleksandra Nevskogo 14, Kaliningrad, 236016, Russia
5Institute for Water and Environmental Problems, Siberian Branch of the Russian Academy of Sciences, ul. Molodezhnaya 1, Barnaul, 656038, Russia
6Geological Institute, Russian Academy of Sciences, Pyzhevskii per. 7/1, Moscow, 119017, Russia
7Tallinn University of Technology, Ehitajate tee 5, Tallinn, 19086, Estonia
Keywords: Terraces, sediment deformations, active tectonics, late Neopleistocene, Holocene, paleoearthquakes, Karelian Isthmus, Vuoksa River, northwestern Russia
Abstract
Terraces at four hypsometric levels were studied in the Vuoksa River basin (northern part of the Karelian Isthmus, NW Russia). New data on nine sections of late Quaternary-Holocene sediments have been obtained. Their age has been determined (for the first time for surface deposits in the studied region) in the interval from 90 to 2 ka. The terrace sediments are disturbed by deformations (faults, folds, and liquefaction) caused by six strong earthquakes in that period. The relationships among the terrace levels, ages, stratigraphy, and structures of loose sediments point to their formation under the impact of differentiated tectonic motions triggered by the activation of the ancient “Vuoksa” fault zone in the late Neopleistocene and Holocene.
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