Formation of terraces in a river valley with active gas-hydrothermal manifestations (the Geysernaya River valley, Kamchatka Peninsula as an example)

The morphology, structure and composition of sediments at low terraces which occur in the form of nonextended fragments in the Geysernaya River valley have been studied. Coarse, poorly sorted and weakly rounded debris flow material of different age generations are dominated in the sections. Layered sand and gravel deposits that accumulated under dammed reservoir conditions were exposed in some areas. Alluvial deposits are represented by thin layers of pebbles with boulders of better roundness and sorting with sand and gravel filler, underlying and/or overlying debris flow deposits. Some fragments of terrace-like surfaces are characterized by a smaller slope compared to the longitudinal profile of the river: apparently, they represent areas of former debris flow – landslide dams. Sediments of modern debris flows can be traced from 0 up to 50 m and of ancient once from 0.5 to 12 m above the river, which indicates the absence of a direct dependence of the age of sediments from the level of their occurrence. The change in loose material is due to the proximity and activity of thermal manifestations of the Geysernoe thermal field. Gas-hydrothermal processes lead to a significant transformation of the composition and properties of the analyzed sediments – mainly to their cementation, which makes it difficult to determine the time of sediment formation. The structure of the studied sections indicates the repeated occurrence of debris flows along the valley and the formation of temporary dammed reservoirs there as a result of the landslides and debris flow dams. The active supply of material from the slopes and its redeposition by debris flows causes poor rounding and sorting of sediment, and its weak disintegration. Among the rock-forming minerals of the fine sand fraction, magnetite and pyroxenes dominate with the participation of ilmenite. The light fraction is represented mainly by opal-smectite-zeolite aggregates, and to a lesser extent by geyserite. In the mineralogical spectra of sediments accumulated in dammed lake conditions, the set of secondary minerals and aggregates is expanding. In the alluvium units underlying the mudflow material there are signs of redeposition of ancient well-rounded sediments.

1. Ananyeva E.G. (1998) Litologo-mineralogicheskiy analiz pri geomorfologicheskikh i paleogeo-graficheskikh issledovaniyakh (Lithological and mineralogical analysis for geomorphologi-cal and paleogeographic studies). Moscow-Smolensk: SGU Publ. 140 р. (in Russ.)

2. Baldina E.A., Lebedeva E.V., and Anikina N.V. (2023) Activity of geomorphological processes on the slopes of river valleys in the conditions of gas-hydrothermal occurrences (based on multi-temporal images and DEM analysis). InterCarto.InterGIS. Vol. 29. P. 272-287 http://dx.doi.org/10.35595/2414-9179-2023-1-29-272-287 (in Russ.)

3. Baldina E.A., Lebedeva E.V., and Medvedev A.A. (2022) Technic for interpretation of archive and recent satellite images to study the slope processes dynamics in the Geysernaya River valley (Kamchatka). InterCarto.InterGIS. Vol. 28. No. 1. P. 266-283. http://dx.doi.org/10.35595/2414-9179-2022-1-28-266-283 (in Russ.)

4. Dvigalo V.N., and Melekestsev I.V. (2009) The geological and geomorphic impact of catastrophic landslides in the Geyser Valley of Kamchatka: Aerial photogrammetryGeological and geo-morphological consequences of catastrophic rockfall and rockfall – landslides processes in the Kamchatka Valley of Geysers (according to aerial photogrammetry). Journal of Vol-canology and SeismologyVulkanologiya i seysmologiya (Volcanology and Seismology). No. 5. P. 24–37. https://doi.org/10.1134/S0742046309050029 (in Russ.)

5. Dvigalo V.N., Svirid I.Yu., Shevchenko A.V., and Zharkov R.V. (2014) Monitoring and forecast-ing of mudflow processes in the Kamchatka Valley of Geysers based on photogrammetric studies. Selevye potoki: katastrofy, risk, prognoz, zashchita: materialy III Mezhdunarodnoi konferentsii, Yuzhno-Sakhalinsk, 22–26 sentyabrya 2014 g.Selevyye potoki: katastrofy, risk, prognoz, zashchita: Mat-ly III Mezhd. konf. (Mudflows: disasters, risk, forecast, pro-tection: Materials III Int. conf.). Yuzhno-Sakhalinsk: Sakhalinskiy filial Dal'nevostochnogo geologicheskogo instituta DVO RAN (Publ.)Sahal. Phil. Far East. Geol. Institute of FEB RAS. P. 105–108. (in Russ.)

6. Frolova Yu.V., Zerkal’ O.V., and Gvozdeva I.P. (2019) The influence of hydrothermal transfor-mations on the physicomechanical properties of tuffogenic rocks of the Valley of Geysers and their role in the formation of landslides. Geodinamicheskiye protsessy i prirodnyye ka-tastrofy: tezisy dokladov III Vserossiyskoy nauchnoy konferentsii s mezhdunarodnym uchastiyem. Yuzhno-Sakhalinsk: Yuzhno-Sakhalinsk: Institut morskoi geologii i geofiziki DVO RAN (Publ.). P. 186. (in Russ.)

7. Geologicheskaya karta (Geological map). Sheet N-57, scale 1: 1,000,000, 3rd edition, 2011 [Elec-tronic resourcedata]. Access wayURL: https://vsegei.ru/ru/info/ggk_1000ns/ (date of ac-cess: 10.11.2023).

8. Geologicheskaya karta (Geological map). Sheet N-57-XXI, N-57-XXII, scale 1:200,000, 1st edi-tion, 1981. [Electronic resourcedata]. Access wayURL: https: //vsegei.ru/ru/info/pub_ggk200-1/ (date of access: 10.11.2023).

9. Kolosova G.N., and Ananyeva E.G. (1974) Methods of mineralogical analysis of unconsolidated deposits for paleogeomorphological studies (with reference to the North-East of the USSR). Geomorfologiya (Geomorphology RAS). No. 4. P.26-35. (in Russ.)

10. Lebedeva E.V. (2021) Gas-hydrothermal activities impact on the relief formation of river valleys geothermal zones // Geomorfologiya (Geomorphology RAS). Vol. 53. No. 5. P. 116- 126. https://doi.org/10.31857/S043542812205008X

11. Lebedeva E.V., Baldina E.A., Medvedev A.A. (2022) Dynamics of Slope Processes in the Gey-sernaya River Valley (Kamchatka) According to the Interpretation Data of Multi-Temporal Space Images. Doklady Earth Sciences. 507 (Suppl 1), S9–S18. http://dx.doi.org/10.1134/S1028334X22601262

12. Lebedeva E.V., Sugrobov V.M., Chizhova V.P., and Zavadskaya A.V. (2020) The valley of the river Geysernaya (Kamchatka): hydrothermal activity and features of relief forming. Geo-morfologiya (Geomorphology RAS). No. 2. P. 60-73. (in Russ.). https://doi.org/DOI: 10.31857/S0435428120020066 (in Russ.)

13. Lebedeva E.V., and Chernomorets S.S. (2023) Debris flow activity and specificity of debris flow formation in the Geysernaya River valley (Kamchatka). Vestnik KRAUNTC. Nauki o Zemle. No. 3. Vol. 349. Iss. 59. P. 5-19. https://doi.org/10.31431/1816-5524-2023-3-59-5-19 (in Russ.)

14. Lebedeva E.V., Zakharov A.L., and Mikhalev D.V. (2023) The Geysernaya River Alluvium (Kamchatka): Composition and Features of Formation. Doklady Earth Sciences. Vol. 513 (Suppl 1), S1–S11. https://doi.org/10.1134/S1028334X23602432

15. Lebedeva E.V., and Zharkov R.V. (2022) Accumulative Landforms in Valleys with Gas-Hydrothermal Occurrences (from the Example of Watercourses of Some Volcanic Massifs in the Kuril—Kamchatka Region). Doklady Earth Sciences. Vol. 506 (Suppl 1), S7–S18 (2022). https://doi.org/10.1134/S1028334X22700131

16. Leonov V.L., Grib E.N., Karpov G.A., Sugrobov V.M., Sugrobova N.G., and Zubin M.I. (1991) Caldera Uzon and the Valley of Geysers. Deystvuyushchiye vulkany Kamchatki (Active volcanoes of Kamchatka). Moscow: Nauka (Publ.). Vol. II. С. 94-141 (in Russ.)

17. Pinegina T.K., Delemen’ I.F., Droznin V.A., Kalacheva E.G., Chirkov S.A., Melekestsev I.V., Dvigalo V.N., Leonov V.L., and Seliverstov N.I. (2008) Kamchatka Valley of Geysers af-ter the catastrophe on 3 June 2007. Vestnik DVO RAN. No. 1. P. 33-44. (in Russ.)

18. Shevchenko A.V., Dvigalo V.N., and Svirid I.Yu. (2018) Remote Studies of Geomorphological Processes at Volcanic Objects of Kamchatka. ХХХVI Plenum GK RAN: Vserossiyskaya nauchno-prakticheskaya konferentsiya s mezhdunarodnym uchastiyem «Geomorfologiya – nauka XXI veka»Plenum Geomorfologicheskoi komissii RAN: Vseros. nauchno-praktich. konf. s mezhd. uchastiyem «Geomorfologiya – nauka XXI veka». Barnaul: ASU Publishing House,. P. 403-410. (in Russ.)

19. Sugrobov V. M., Sugrobova N. G., Droznin V. A., Karpov G. A., and Leonov V. L. (2009) Zhemchuzhina Kamchatki – Dolina Geyzerov. Nauchno-populyarnyy ocherk, putevoditel' (The Pearl of Kamchatka is the Valley of Geysers. Popular science essay, guide). Petropav-lovsk-Kamchatsky: Kamchatpress (Publ.) 108 p. (in Russ.)

20. Ustinova T.I. (1955) Kamchatskiye geyzery (Kamchatka geysers). Moscow: Geografgiz (Publ.). 120 p. (in Russ.)

21. Zavadskaya A.V. (Ed.). (2015) Atlas doliny reki Geyzernoy v Kronotskom zapovednike (Atlas of the valley of the River Geysernaya in Kronotsky Reserve). M.: KRASAND (Publ.). 88 p. (in Russ.)

22. Zerkal’ O.V., Gvozdeva I.P., and Frolova Yu.V. (2019) The development of landslide processes in the valley of the river Geysernaya. Geodinamicheskie protsessy i prirodnye katastrofy: tezisya dokladov III Vserossiyskoi nauchnoi konferentsii s mezhdunarodnym uchastiem, g. Yuzhno-Sakhalinsk, 27– 31 maya 2019 g.Geodinamicheskiye protsessy i prirodnyye ka-tastrofy: tezisy dokladov III Vserossiyskoy nauchnoy konferentsii s mezhdunarodnym uchastiyem. Yuzhno-Sakhalinsk: Institut morskoi geologii i geofiziki DVO RAN (Publ.). P. 138. (in Russ.)