Hydrogeochemical zoning of uranium isotopes (²³⁴U/ ²³⁸U) in the Southern Siberian paleocontinent: the role of the South Baikal reservoir in the groundwater formation

The southern deformed edge of the Siberian paleocontinent is studied for zoning the disturbance of ²³⁴U/²³⁸U cyclic equilibrium in groundwaters discharged to the accreted Khamardaban terrane. A relationship is established between vertical variations of ²³⁴U/²³⁸U (ОА4/8) activity ratios and the hydrogeochemical zoning of groundwaters. Lateral ОА4/8 zoning of groundwaters in the basement rocks and sedimentary cover of the Siberian platform is described. It is emphasized that an important role is played by the water propagating from the South Baikal reservoir (SBR) (ОА4/8 = 1.95–1.99; U content = 0.44–0.46 μg/L) under the shore of Lake Baikal. It is suggested that the lateral advancement of the SBR water is facilitated by the development of low-angle (weakened by rifting) fractures of the Angara thrust fault, as well as subvertical fractures in the shear zone of the Main Sayan Fault. Monitoring data on the study area show that the ratios of the groundwaters components vary in time due to Cherdyntsev – Chalov deformational effect, chemical interaction of the waters and evaporites, and mixing of the groundwaters with contrasting hydrogeochemical signatures.

1. Alekseeva L.P., Alekseev C.V., 2019. Geochemistry of Underground Ice, Salt Water and Brines of Western Yakutia. GEO, Novosibirsk, 214 p. (in Russian) https://doi.org/10.21782/B978-5-6043021-2-5.

2. Chabaux F., Bourdon B., Riotte J., 2008. U-Series Geochemistry in Weathering Profiles, River Waters and Lakes. Radioactivity in the Environment 13, 49–104. https://doi.org/10.1016/S1569-4860(07)00003-4.

3. Chabaux F., Granet M., Larqué Ph., Riotte J., Skliarov E.V., Skliarova O., Alexeieva L., Risacher F., 2011. Geochemical and Isotopic (Sr, U) Variations of Lake Waters in the Ol’khon Region, Siberia, Russia: Origin and Paleoenvironmental Implications. Comptes Rendus Geoscience 343 (7), 462–470. https://doi.org/10.1016/j.crte.2011.07.004.

4. Chalov P.I., 1975. Isotopic Fractionation of Natural Uranium. Ilim, Frunze, 236 p. (in Russian)

5. Chebykin E.P., Rasskazov S.V., Vodneva E.N., Ilyasova A.M., Chuvashova I.S., Bornyakov S.A., Seminsky A.K., Snopkov S.V., 2015. The First Results of Monitoring 234U/238U in Water from Active Faults of the Western Coast of Southern Baikal. Doklady Earth Sciences 460, 464–467. https://doi.org/10.1134/S1028334X15020075.

6. Chebykin E.P., Sorokovikova L.M., Tomberg I.V., Vodneva E.N., Rasskazov S.V., Chuvashova I.S., Khodzher T.V., Grachev M.А., 2018. Seasonal Variability of Major and Trace Elements and the 234U/238U Ratio in the Selenga River – Main Tributary of Lake Baikal (Russian Part of the River). In: P. Vossen, D. Karthe, B. Gunsmaa, S. Enkhjargal (Eds), Book of Abstracts GMIT Symposium on Environmental Science and Engineering. GMIT, Nalaikh, 64–65.

7. Chebykin E.P., Sorokovikova L.M., Tomberg I.V., Vodneva E.N., Rasskazov S.V., Khodzher T.V., Grachev M.A., 2012. Current State of Waters of the Selenga River in the Territory of Russia According to the Main Components and Trace Elements. Chemistry in the Interests of Sustainable Development 20, 613–631 (in Russian)

8. Cherdyntsev V.V., 1969. Uranium–234. Atomizdat Press, Moscow, 308 p. (in Russian)

9. Cherdyntsev V.V., 1973. Nuclear Volcanology. Nauka, Moscow, 208 p. (in Russian)

10. Chipizubov A.V., Smekalin O.P., 1999. Paleoseismodislocations and Related Paleoearthquakes at the Main Sayan Fault Zone. Geology and Geophysics 40 (6), 936–947 (in Russian)

11. Danilovich V.N., 1949. New Data on the Angarsk Thrust. Bulletin of the Academy of Sciences. Geology Series 4, 69–77 (in Russian)

12. Danilovich V.N., 1963. Arkogenic Type of Thrusts. Geology and Geophysics 2, 3–11 (in Russian)

13. Edgington D.N., Robbins J.A., Colman S.M., Orlandini K.A., Gustin M.-P., 1996. Uranium-Series Disequilibrium, Sedimentation, Diatom Frustules and Paleoclimate Change in Lake Baikal. Earth and Planetary Science Letters 142 (1–2), 29–42. https://doi.org/10.1016/0012-821X(96)00085-4.

14. Finkel R.C., 1981. Uranium Concentrations and 234U/238U Activity Ratios in Fault-Associated Groundwater as Possible Earthquake Precursors. Geophysical Research Letters 8 (5), 453–456. https://doi.org/10.1029/GL008i005p00453.

15. Grudinin M.I., Chuvashova I.S. (Eds), 2011. Baikal. Geology. Human Being. ISU Publishing House, Irkutsk, 239 p. (in Russian)

16. Logatchev N.A., Zorin Yu.A., 1992. Baikal Rift Zone: Structure and Geodynamics. Tectonophysics 208, 273–286.

17. Odintsova M.M., Gutova L.N., Bogdasheva L.I., 1967. Stratigraphy. In: Jurassic Continental Sediments in the Southern Siberian Platform. Nauka, Moscow, 19–118 (in Russian)

18. Pampura V.D., Sandimirov I.V., Gapon A.E., Chernaya L.I., Ulybusheva E.I., 1996. Distribution and Isotopic Composition of Uranium in the Calculated Runoff and Water of Lake Baikal. Reports of the Academy of Sciences 350 (6), 672–676. (in Russian)

19. Pinneker E.V., Pisarsky B.I., Lomonosov I.S., Koldysheva R.Ya., Didenko A.A., Sherman S.I., 1968. Hydrogeology of the Baikal region. Nauka, Moscow, 170 p. (in Russian)

20. Rasskazov S.V., Chebykin E.P., Ilyasova А.М., Vodneva Е.N., Chuvashova I.S., Badminov P.S., Orgilyanov A.I., Kryukova I.G., Ageev A.O., 2015a. Concentrations and Isotopic Composition of Uranium and Strontium in Water of Lake Baikal. In: Geological Evolution of Water–Rock Interaction. Proceedings of Second All-Russia Scientific Conference with International Participation (September 06–11, 2015). Dal’nauka, Vladivostok, 397–399 (in Russian)

21. Rasskazov S.V., Chebykin E.P., Ilyasova А.М., Vodneva Е.N., Chuvashova I.S., Bornyakov S.А., Seminsky А.К., Snopkov S.V., Chechel’nitsky V.V., Gileva N.А., 2015b. Creating the Kultuk Polygon for Earthquake Prediction: Variations of (234U/238U) and 87Sr/86Sr in Groundwater from Active Faults at the Western Shore of Lake Baikal. Geodynamics & Tectonophysics 6 (4), 519–553 (in Russian) https://doi.org/10.5800/GT-2015-6-4-0192.

22. Rasskazov S.V., Ilyasova A.M., Chuvashova I.S., Chebykin E.P., 2018. The 234U/238U Variations in Groundwater from the Mondy Area in Response to Earthquakes at the Termination of the Tunka Valley in the Baikal Rift System. Geodynamics & Tectonophysics 9 (4), 1217–1234 (in Russian) https://doi.org/10.5800/GT-2018-9-4-0392.

23. Salnikova E.B., Sergeev S.A., Kotov A.B., Yakovleva S.Z., Steiger R.H., Reznitskiy L.Z., Vasil’ev E.P., 1998. U–Pb Zircon Dating of Granulite Metamorphism in the Sludyanskiy Complex, Eastern Siberia. Gondwana Research 1 (2), 195–205. https://doi.org/10.1016/S1342-937X(05)70830-3.

24. Seminsky K.Zh., Gladkov A.S., Lunina O.V., 2001. Tectonophysical Characteristics of the Angarsk Fault Zone (South of the Siberian Platform). Geology and Geophysics 42 (8), 1252–1262 (in Russian)

25. Seminsky K.Zh., Radziminovich Y.B., 2007. Seismicity of the South of the Siberian Platform: Spatio-Temporal Characteristics and Genesis. Physics of the Earth 9, 18–30 (in Russian)

26. Skoblo V.M., Lyamina N.A., Rudnev A.F., Luzina I.V., 2001. Continental Upper Mesozoic of the Pribaikalie and Transbaikalia. SB RAS Publisher, Novosibirsk, 332 p. (in Russian)

27. Suvorov V.D., Mishen’kina Z.R., 2005. Structure of Sedimentary Deposits and Basement under the Southern Basin of Lake Baikal According to Correlated Seismic Refraction Data. Geology and Geophysics 46 (11), 1159–1167 (in Russian)

28. Tokarev I., Zubkov A.A., Rumynin V.G., Polyakov V.A., Kuznetsov V.Yu., Maksimov F.E., 2006. Origin of High 234U/238U Ratio in Post-Permafrost Aquifers. In: B.J. Merkel, A. Hasche-Berger (Eds), Uranium in the Environment. Mining Impact and Consequences. Springer, Berlin, Heidelberg, 847–856. https://doi.org/10.1007/3-540-28367-6_88.

29. Ulomov V.I., Bogdanov M.I., 2016. Set of General Seismic Zoning Maps for the Territory of the Russian Federation, OSR-2016 (in Russian)

30. Votintsev K.K., 1961. Hydrochemistry of Lake Baikal. Proceedings of the Baikal Limnological Station, USSR Academy of Sciences 20, 311 p. (in Russian)

31. Yamamoto M., Sato T., Sasaki K., Hama K., Nakamura T., Komura K., 2003. Anomalously High 234U/238U Activity Ratios of Tatsunokuchi Hot Spring Waters, Ishikawa Prefecture, Japan. Journal of Radioanalytical and Nuclear Chemistry 255 (2), 369–373. https://doi.org/10.1023/a:1022573208205.

32. Zamaraev S.M., Sizykh V.I., Meshalkin S.I., Novokshonov Yu.A., 1983. Structural Features of the Angarsk Thrust. Geology and Geophysics 5, 126–129 (in Russian)

33. Zverev V.L., Dolidze N.I., Spiridonov A.I., Cheshko A.L., Chkhenkeli Sh.M., 1975. Anomaly of the Even Uranium Isotopes in the Groundwater of Seismically Active Regions of Georgia. Geochemistry 11, 1720–1724 (in Russian)