The structure of the Shura-Ozen’ river valley nearby the Sarykum aeolian-accumulative complex (Republic of Dagestan, Southern Russia)

The Shura-Ozen’ River originales in the low mountains of the northeast of the Great Caucasus and flows into the Caspian Sea in the north of the city of Makhachkala (Republic of Dagestan, Russia). The paper presents the results of its geomorphological study based on grain size and mineralogical analyzes, and geologicalgeophysical profiling. The study area is located near the aeolian-accumulative complex Sarykum, which is one of the largest isolated (i.e., formed away from deserts) aeolian sandy landforms in Eurasia. There are two principal groups of terraces differed sharply by their structure. The first group is presented by the floodplain and the high (V and VI) terraces, which are composed by overbank and riverbed alluvial   facies with normal thickness. The second group unites the terraces I, III and IV characterized by much higher thickness of alluvial overbank sands, evident especially in the terrace IV. The formation time of Terrace VI occurred before the Atelian regression (i.e. presumably in Late Girkan epoch (?), more than 44–41 cal.ka BP), Terrace V – in Early Khvalynian epoch (app. 40–33 cal.ka BP). Terrace IV formation coincided the Mid Khvalynian epoch (app. 33–(25)20 cal.ka BP), between the two deep incisions of the river correlated with the El’ton and Enotaev regressions of the palaeo-Caspian Sea. Terrace III formation occurred in Late Khvalynian epoch (app. (25)20–12 cal.ka BP), between the Enotaev and Mangyshlak regressions. All lower terraces and floodplain of the river valley are dated to the Holocene. Consequently, it could preliminarily be assumed that the Shura-Ozen’ River valley formation in its present form, as well as formation of the Sarykum sands originated from proluvial-deltaic deposits, occurred more than 44–41 cal.ka BP. (or 41-37 ka BP).

Analysis of granulometric spectra of the alluvial sediments made it possible to draw an important conclusion that the most active phase of dune formation within the aeolian-accumulative complex Sarykum took place in the epoch preceding the formation of the river terraces, i.e. after the formation of proluvial-deltaic sands, but before the valley formation. It is also assumed that the relic marine sandy spits and the pebble coastal bar (to the north of Sarykum) are genetically linked with the alluvial deposits of the terrace III and the terrace V, respectively.

1. Idrisov I.A. Features of development of the Dagestan’s river valleys. Izv. Dag. Ped. Univ. 2013. No. 3 (24). P. 84–90. (in Russ.)

2. Nikitin M. Yu. River terraces and recent tectonics of the mountainous Dagestan (the River Sulak basin). Bul. MOIP. Otd. Geol.1979. Vol. 54. Iss. 5. P. 88–104. (in Russ.)

3. Tulysheva E.V. and Khlopkova M.V. About some features of development of river valleys of orogenic and flat (Caspian lowland) parts of the Eastern Caucasus region. Tr. Ins. Geol. Dag. NC RAN. 2012. No. 58. P. 51–53. (in Russ.)

4. Fyodorov P.V. The stratigraphy of Quaternary deposits and the history of development of the Caspian Sea. Tr. GIN AN SSSR. Moscow: Academy of Sciences of the USSR (Publ.), 1957. Vol. 10. 155 p. (in Russ.)

5. Rychagov G.I.Pleistotsenovaya istoriya Kaspiyskogo morya (The Pleistocene history of the Caspian Sea). Moscow: MGU (Publ.), 1997. 267 p.

6. Gusarov A.V. Aeolian-accumulative complex Sarykum as a unique geomorphic object of Russia: research history and hypotheses of origin. Geomorfologiya (Geomorphology RAS). 2015. No. 2. P. 54–71. (in Russ.). doi: 10.15356/0435-4281-2015-2-54-71.

7. Gusarov A.V. Aeolian-accumulative complex Sarykum as a unique geomorphic object of Russia: the structure, genesis and sources of its sands. Geomorfologiya (Geomorphology RAS). 2016. No. 3. P. 52–78. (in Russ.). doi: 10.15356/0435-4281-2016-3-52-78.

8. Idrisov I.A. To the history of formation and development of the Sarykum sandy massif. Tr. Dos. Prir. Zap. Dag. 2010. Vol. 3. P. 19–27. (in Russ.)

9. Barbot de Marni N.N. The report on geological studies in the Temirkhan-Shurinsky district of the Dagestan region, in Materialy po geologii Kavkaza (Proc. on the geology of Caucasus). Tiflis. 1894. Vol. 2. Book 8. P. 228–409.

10. Gusarov A.V., Sharifullin A.G. and Dzhamirzoev G.S. The contemporary height of aeolian accumulative complex Sarykum (Republic of Dagestan) and the causes of its change. Izv. Akad. Nauk. Ser. Geogr. 2017. No. 6. P. 147–156 (in Russ.). doi: 10.7868/s0373244417060081.

11. Frolov V.T.Litologiya(Lithology). Moscow: MGU (Publ.), Vol. 2. 1993. 432 p.

12. Yapaskurt O.V.Litologiya (Lithology). Moscow: Akademiya (Publ.), 2008. 336 p.

13. Krasheninnikov G.F.Uchenie o fatsiyah (Doctrine of facies). Leningrad: Vysshaya shkola (Publ.), 1971. 368 p.

14. Rychagov G.I. Girkan stage in the history of the Caspian Sea. Geomorfologiya (Geomorphology RAS). 2016. No. 1. P. 3–17. (in Russ.). doi: 10.15356/0435-4281-2016-1-3-17.

15. Bezrodnykh Yu.P., Sorokin V.M. and Yanina T.A.About the Atelian regression of the Caspian Sea. Vestn. Mosk. Univ. Ser. 5. Geogr.2015. No. 2. P. 77–85. (in Russ.)

16. Vereshchagina V.S. The stratigraphy of Quaternary sediments of western slope of the Central Ural Mountains and Cis-Ural, in Stratigrafiya chetvertichnykh(antropogenovykh) otlozheniy Urala(The Quaternary (Anthropogenic) stratigraphy of deposits of the Ural Mountains). Moscow: Nedra (Publ.), 1965. P. 106–129.

17. Varuschenko S.I., Varuschenko A.N. and Klige R.K.Izmenenie rezhima Kaspiyskogo morya i besstochnykh vodoemov v paleovremeni (Changing of regime of the Caspian Sea and closed lakes in paleotime). Moscow: Nauka (Publ.), 1987. 240 p.

18. Bezrodnykh Yu P., Romanyuk B.F., Deliya S.V., Magomedov R.D., Sorokin V.M., Parunin O.B., and Babak E.V. Biostratigraphy and structure of the Upper Quaternary deposits and some paleogeographic features of the North Caspian region. Stratigraphy and Geological Correlation. 2004. No. 12. P. 102–111.

19. Ollivier V., Fontugne M., and Lyonnet B. Geomorphic response and 14 C chronology of base-level changes induced by Late Quaternary Caspian Sea mobility (middle Kura Valley, Azerbaijan). Geomorphology.2015. Vol. 230. P. 109–124. DOI: 10.1016/j.geomorph.2014.11.010.

20. Butakov G.P. From Kazan to the Sviyaga River mouth, in Srednyaya Volga: geomorfologicheskiy putevoditel (Middle Volga: geomorphic guidebook). A.P. Dedkov. Ed. Kazan: Izd-vo Kazan Un-ta (Publ.), 1991. p. 41–48.

21. Svitoch A.A. Regressive periods of the Great Caspian. Water Resources. 2016. Vol. 43. Issue 2. P. 270–282. DOI: 10.1134/S0097807816020160.

22. Sayadyan Yu.V. Structure of river terraces of the Minor Caucasus. Geomorfologiya (Geomorphology RAS). 2015. No. 3. P. 102–108. (in Russ.). doi: 10.15356/0435-4281-2015-3-102-108.