Neotectonics and Geological Structure of the Sevan Intermountain Basin (Armenia): New Structural and Paleontological Data

Abstract

The article presents new data obtained as a result of field research in 2022 Sevan intermountain depression in Armenia. The emergence of the Sevan intermountain depression in the Miocene was associated with the development of the Sevan almond-shaped structure, bounded by the right-lateral Pambak‒Sevan‒Syunik fault zone in the northeast, the Garni zone in the south, and the Arpa‒Zangezur zone in the southwest. Within the Sevan almond-shaped structure, strike-slip structures of Small Sevan (western part of Lake Sevan) and Gavar almond-shaped structure, Gavar horst, a number of faults, as well as extension zones were formed, including the southern part of Greater Sevan (eastern part of Lake Sevan) and axial zone of the Geghama Range. The development of the Sevan intermountain depression continued in the Pliocene under the influence of the uplift of the Lesser Caucasus and the Armenian Highlands. We have summarized the available data on the geological structure and geodynamics of the Sevan intermountain depression, presented the obtained data on the stratigraphy of the Pliocene–Quaternary deposits and their position, and showed that during the Akchagyl transgression at the Pliocene–Pleistocene boundary, sedimentary accumulations did not occur in the Sevan intermountain depression.