The signs of inherited neotectonic development of the Mologo-Sheksna depression area

The artThe article is devoted to the consideration of the contribution of tectonic and neotectonic processes to the formation of the Mologo-Sheksna depression, as well as clarification of its structural features and the nature of the inheritance of its formation. Lineament, morphological and morphostructural analyzes are used as a methodological approach. The Mologo-Sheksna depression, currently filled with the Rybinsk Sea, has signs of an inherited developing morphostructure. It is a graben-shaped depression with linear northeastern and southwestern sides. The depression is located above the graben, which is well expressed in the basement and the lower part of the cover complexes, and, also has an expression in the top of pre-Quaternary rocks. A depression was formed on the site of an area of insignificant tectonic subsidence, and the origin of its contrasting relief is mainly associated with the activity of glaciers, the traces of which were then partly smoothed out by late-post-glacial lakes and water flows. The development of the depression was influenced by the surrounding faults. This impact was expressed not so much by high-amplitude displacements (corresponding to the range of the topography or top of the surface of pre-Quaternary deposits), but by the formation of zone of weakness with increased fracturing, which controlled the manifestation of exaration and abrasion processes. Field studies confirmed the existence of an additional landscape lineament along the southwestern side of the depression, the formation of which can be explained by the existence of another zone of weakness with fractures above the Rybinsk Fault. Measurements of the orientation of fractures in outcrops in the near-edge part of the Sit’ River valley showed the coincidence of the strike of the main systems of fractures, basement faults and the main morphological elements of the area, in particular, the side scarp of the reservoir, which indicates its tectonic predetermination.

1. Yudahin F.N., Shchukin Yu.K., and Makarov V.I. Glubinnoe stroenie i sovremennye geodinamicheskie protsessy v litosfere Vostochno-Evropeiskoi platformy (Deep structure and modern geodynamic processes in the lithosphere of the East European Platform). Ekaterinburg: UrO RAN (Publ.), 2003. 299 p.

2. Kopp M.L. Mobilisticheskaya neotektonika platform Jugo-Vostochnoi Evropy (Mobilistic neotectonics of platforms of southeastern Europe). Moscow: Nauka (Publ.), 2004. 304 p.

3. Novsky V.A. Pleistotsen Yaroslavskogo Povolzh’ya (Pleistocene of the Yaroslavl Volga region). Moscow: Nauka (Publ.), 1975. 236 p.

4. Kozhevnikov A.V., Naidina O.D., Semenov V.M., and Hamster S.V. Upper Pleistocene of the Onega NonHumus Region. Byull. MOIP. Otd. Geol. 1983. Vol. 58(1). P. 120–142. (in Russ.)

5. Borodin N.G., Shatalova O.N., Dashevsky V.V., Sokolova T.D., and Bastrakova N.V. Explanatory note to the state geological map of the USSR. Scale 1: 200000. Moscow series. Sheets O-37-XIV, XV, XVI, XXI. M.I. Lopatnikov (Ed.). Moscow: PGO Tsentrgeologiya MGRE (Publ.), 1985. 219 p. (in Russ.)

6. Trifonov V.G. Neotectonica Evrazii (Neotectonics of Evrasia). Trudy GIN RAN (Transactions of the GIN RAS). 1999. Vol. 514. 242 p.

7. Chamov N.P. Stroenie i razvitie Srednerussko-Belomorskoi provintsii v neoproterozoe (The structure and development of the Central Russian-Belomorian Province in Neoproterozoic). Moscow: GEOS (Publ.), 2016. 233 p.

8. Agibalov A.O. Neotektonicheskaya aktivizatsiya dokembriiskogo strukturnogo plana Severnogo Priladozh’ya (yugo-vostok Baltiiskogo shchita) (Neotectonic activation of the Precambrian structural plan of the Northern Ladoga (southeast of Baltic shield)). PhD thesis. Moscow: MSU (Publ.), 2019. 23 p.

9. Dmitrovskaya Yu.E. and Kheraskova T.N. Paleogeograficheskie i geodinamicheskie obstanovki formirovaniya pozdnevendskikh i kembriiskikh otlozhenii v tsentral’noi chasti Vostochno-Evropeiskoi platformy (Paleogeographic and geodynamic conditions of formation of late Vendian and Cambrian deposits in the Central part of the East European platform). Litologiya i poleznye iskopaemye (Lithology and mineral resources RAS). 1999. No. 6. P. 1–12. (in Russ.).

10. Zastrozhnova O.I., Krotova-Putintseva A.E., Lukyanova N.V., Kirikov V.P., Kossovaya O.L. et al. Ob’yasnitel’naya zapiska k gosudarstvennoi geologicheskoi karte Rossiiskoi Federatsii. Masshtab 1: 1000000 (tret’e pokolenie). List O-37 (Yaroslavl’) (Explanatory note to the state geological map of the Russian Federation. Scale 1: 1000000 (third generation). Sheet O-37 (Yaroslavl)). V.P. Kirikov (Ed.). SPb.: VSEGEI (Publ.), 2015. 356 p. (in Russ.).

11. International tectonic map of Europe and adjacent areas. Scale 1: 2500000. A.A. Bogdanov and V.E. Hain (Eds.). M.: GUGK (Publ.), 1981.

12. Gavrilov V.P., Dvoretsky P.I., Dunaev V.F., Ponomarev V.A., and Rudnev A.N. Geologiya i neftegazonosnost' Moskovskoi i Mezenskoi sinekliz (Geology and oil and gas potential of the Moscow and Mezen syneclises). Moscow: Gazprom (Publ.), 2000. 157 p.

13. Moskvitin A.I. Mologo-Sheksninskoe mezhlednikovoe ozero (Mologo-Sheksna interglacial lake). Proceedings of the Institute of Geological Sciences of the USSR Academy of Sciences. Issue 88. Geological series (No. 26). 1947. P. 5–18.

14. Breslav S.L. Chetvertichnaya sistema. Geologiya SSSR. T. IV. Centr Evropeiskoi chasti SSSR: (Moskovskaya, Vladimirskaya, Ivanovskaya, Kalininskaya, Kaluzhskaya, Kostromskaya, Ryazanskaya, Tul’skaya, Smolenskaya i Yaroslavskaya oblasti): geologicheskoe opisanie (Quaternary system. Geology of the USSR. Vol. IV: Center of the European part of the USSR: (Moscow, Vladimir, Ivanovsk, Kalinin, Kaluga, Kostroma, Ryazan, Tula, Smolensk and Yaroslavl regions): geological description). A.V. Sidorenko (Ed.). Moscow: Nedra (Publ.), 1971. P. 489–637.

15. Barashkova Z.K. Karta chetvertichnykh otlozhenii. List O-37(38): Nizhnii Novgorod. Gosudarstvennaya geologicheskaya karta Rossiiskoi Federatsii. Masshtab 1:1000000 (novaya seriya) (Quaternary sediment map. Sheet O-37 (38): Nizhny Novgorod. State geological map of the Russian Federation. Scale 1: 1000000 (new series)). S.M. Shik, V.P. Kirikov (Eds.). S.-Petersburg: VSEGEI (Publ.), 1999.

16. Spiridonov A.I. Geomorfologiya Evropeiskoi chasti SSSR (Geomorphology of the European part of the USSR). Moscow: Vysshaya shkola (Publ.), 1978. 336 p.

17. Kvasov D.D. Pozdnechetvertichnaya istoriya krupnykh ozer i vnutrennikh morei Vostochnoi Evropy (Late Quaternary history of large lakes and inland seas of Eastern Europe). Leningrad: Nauka (Publ.), 1975. 278 p.

18. Simonova G.F. and Borodin N.G. Karta chetvertichnykh otlozhenii. Moskovskaya seriya. List O-37-XIV: Krasnyi kholm. Gosudarstvennaya geologicheskaya karta SSSR. Masshtab 1:200000 (Quaternary sediment map. Moscow series. Sheet O-37-XIV: Krasnyj holm. State geological map of the USSR. Scale 1:200000). M.I. Lopatnikov (Ed.). Leningrad: VSEGEI (Publ.), 1985.

19. Shatskii N.S. Sravnitel’naya tektonika drevnikh platform. St. 5. O proiskhozhdenii Pachelmskogo progiba. (Comparative tectonics of ancient platforms. Paper. 5. On the origin of the Pachelm trough). Byull. MOIP. Otd. geol. 1955. T. 30. No. 5. P. 5–26.

20. Khavin E.I. Geologicheskoe opisanie marshruta po uchastkam Rybinsk–Cherepovets–Beloe ozero (Geological description of the route along the sections Rybinsk–Cherepovets–Beloe Ozero). Geologicheskii putevoditel' po kanalu im. Moskvy i Volgo-Baltiiskomu vodnomu puti im. V.I. Lenina (Geological guide to the Moscow Canal and the Volga-Baltic waterway named after V.I. Lenin). Leningrad: Nauka (Publ.), 1968. P. 113–119. (in Russ.)

21. Lobanov A.I. Korrelyatsionnye priznaki tillov tsentra Rossii (Correlation signs of tills in the center of Russia). Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya Geologiya. 2002. No. 2. P. 27–40. (in Russ.)

22. Kiselev D.N., Baranov V.N., Muravin E.S., Novikov I.V., and Sennikov A.G. Atlas geologicheskikh pamyatnikov prirody Yaroslavskoi oblasti (Atlas of geological natural monuments of the Yaroslavl region). Yaroslavl: YAGPU (Publ.), 2003. 120 p. (in Russ.)

23. Makarova N.V. and Sukhanova T.V. Geomorfologiya. Uchebnoe posobie (Geomorphology. Tutorial). M.: KDU (Publ.), 2007. 414 p.

24. Meshcheryakov Yu.A. Strukturnaya geomorfologiya ravninnykh stran (Structural geomorphology of lowland countries). Moscow: Nauka (Publ.), 1965. 390 p.