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Uranium Isotopic Fractionation (234U, 238U) in the Formation of Ice Crystals. C. 15–23

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Section: Geosciences




Evgeniy Yu. Yakovlev*, Georgiy P. Kiselev*, Sergey V. Druzhinin*, Sergey B. Zykov*
*Federal Center for Integrated Arctic Research, Russian Academy of Sciences (Arkhangelsk, Russian Federation)


Since the discovery of the uranium even isotopes fractionation (Cherdyntsev – Chalov effect) some of the researchers have developed a firm conviction that the separations of uranium isotopic pairs 234U and 238U does not occur in mineral systems, and the fractionation is possible only in the transition from the solid phase to the liquid one because of the different isotopic mobility. The observed excess 234U isotope in the total uranium of various minerals and rocks, with the significantly higher age than the period of the secular equilibrium establishment, was explained by the authigenic origin or background whitening of the migrational uranium. Disequilibrium uranium was found later in ore minerals; its origin was difficult to explain by the authigenic nature. However, now the problem of the 234U kinetics and formation of variations of isotopic ratio 234U/238U in natural environments remains unsolved. In this context, we have got the idea of an experiment to monitor the formation of non-equilibrium uranium in the solid phase formation from the solution with a known isotopic composition through the example of water crystallization at freezing, as the most accessible experimental system. The experimental studies of uranium isotopic fractionation in the formation of ice crystals at the partial freezing of trapped fluid are carried out. The forming ice is depleted by isotope 234U, and the residual water is enriched by the radiogenic uranium atoms. A parent nuclide 238U and a daughter product 234U, connected by a single decay chain, in the solid phase formation behave differently, which confirms the existence of uranium in water in two forms: dissolved uranium in the form of individual compounds and uranium, which is in a mineral particle separated by a recoil nucleus 234Th from the rock at entering the water.


uranium isotope, alpha decay, ice crystal, isotopic fractionation, 234U/ 238U
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  1. Ferronskiy V.I., Polyakov V.A. Izotopiya gidrosfery Zemli [Isotopy of the Earth’s Hydrosphere]. Moscow, 2009. 632 p. 
  2. Vasil’chuk Y.K. Ehksperimental’noe izuchenie izotopnogo frakcionirovaniya pri konzhelyacionnom l’doobrazovanii [Experimental Study of the Isotopic Fractionation During the Congelation Ice Formation]. Kriosfera Zemli [Earth Cryosphere], 2011, vol. XV, no. 3, pp. 51–55. 
  3. Cherdyncev V.V., Chalov P.I. Estestvennoe razdelenie 234U/238U [The Natural Separation of 234U and 238U]. Otkrytiya v SSSR [Discoveries in the USSR]. Moscow, 1977, pp. 28–31. 
  4. Cherdyncev V.V. Uran-234 [Uranium-234]. Moscow, 1969. 299 p. 
  5. Chalov P.I. Izotopnoe frakcionirovanie prirodnogo urana [Isotopic Fractionation of Natural Uranium]. Frunze, 1975. 236 p. 
  6. Koide M., Golberg E. 234U/238U ration in Sea Water. Prog. Oceanography, 1965, vol. 3, p. 173. 
  7. Kiselev G.P. Chetnye izotopy urana v geosfere [Even Uranium Isotopes in the Geosphere]. Yekaterinburg, 1999. 220 p. 
  8. Riotte J., Chabaux F. (234U/238U) Activity Ratios in Freshwaters as Tracers of Hydrological Processes: The Strengbach Watershed (Vosges, France). Geochimica et Cosmochimica Acta, 1999, vol. 63(9), pp. 1263–1275. 
  9. Roback R.C., Johnson T.M., McLing T.L., Murrell M.T., Luo S., Ku T.-L. Uranium Isotopic Evidence for Groundwater Chemical Evolution and Flow Patterns in the Eastern Snake River Plain Aquifer, Idaho. Geological Society of America Bulletin, 2001, vol. 113, no. 9, pp. 1133–1141. 
  10. Luo S., Ku T.-L., Roback R.C., Murrell M.T., McLing T.L. In-situ Radionuclide Transport and Preferential Groundwater Flows at INEEL (Idaho): Decay-Series Disequilibrium Studies. Geochimica et Cosmochimica Acta, 2000, vol. 64, no. 5, pp. 867–881. 
  11. Maher K., DePaolo J.C., Christensen J.N. U–Sr Isotopic Speedometer: Fluid Flow and Chemical Weathering Rates in Aquifers. Geochimica et Cosmochimica Acta, 2006, vol. 70, pp. 4417–4435. 
  12. Osmond J.K., Rydell H.S., Kaufman M.I. Uranium Disequilibrium in Groundwater: an Isotope Dilution Approach in Hydrologic Investigations. Science, 1968, vol. 162, no. 3857, pp. 997–999. 
  13. Grzymko T.J., Marcantonio B.A., McKee C.M., Stewart C.M. Temporal Variability of Uranium Concentrations and 234U/238U Activity Ratios in the Mississippi River and Its Tributaries. Chemical Geology, 2007, vol. 243, pp. 344–356. 
  14. Maher K., DePaolo J.C., Lin F. Rates of Silicate Dissolution in Deep-Sea Sediment: In Situ Measurement Using 234U/238U of Pore Fluids. Geochimica et Cosmochimica Acta, 2004, vol. 68, no. 22, pp. 4629–4648. 
  15. Andersen M.B., Erel Y., Bourdon B. Experimental Evidence for 234U–238U Fractionation During Granite Weathering with Implications for 234U/238U in Natural Waters. Geochimica et Cosmochimica Acta, 2009, vol. 73, pp. 4124–4141. 
  16. Kiselev G.P. Prognoz mestorozhdeniy poleznykh iskopaemykh i zagryazneniya geologicheskoy sredy uranizotopnymi metodami: avtoref. dis. ... d-ra geol.-mineral. nauk [The Forecast of Mineral Deposits and Contamination of the Geological Environment by the Uranium-Isotope Methods: Dr. Geol.-Mineral. Sci. Diss. Abs.]. Arkhangelsk, 2005. 50 p. 
  17. Ezhova M.P., Polyakov V.A. Sposob poiska kimberlitov v rayonakh proyavleniya kimberlitovogo magmatizma [The Method of Kimberlites Exploration in the Areas of Kimberlite Magmatism Evidence]. Certificate of Authorship USSR, no. SU 970 986, 1981. 
  18. Malov A.I., Kiselev G.P. Uran v podzemnykh vodakh Mezenskoy sineklizy [Uranium in the Mezen Syncline Groundwaters]. Yekaterinburg, 2008. 238 p. 
  19. Metodika izmereniy ob”emnoy aktivnosti izotopov urana (238U, 234U, 235U) v probakh prirodnykh (presnykh i mineralizovannykh), tekhnologicheskikh i stochnykh vod al’fa-spektrometricheskim metodom s radiokhimicheskoy podgotovkoy [Methods of Measurement of Volumetric Activity of Uranium Isotopes (238U, 234U, 235U) in the Samples of Natural (Fresh and Salt), Process and Waste Waters by Alpha Spectrometry with Radiochemical Preparation]. Moscow, 2013. 15 p. 
  20. Metodicheskoe rukovodstvo po uran-izotopnomu modelirovaniyu dinamiki podzemnykh vod v usloviyakh aktivnogo vodoobmena [A Guidelines for Uranium Isotope Modeling of the Groundwaters Dynamics in Terms of Active Water Exchange]. Bishkek, 1991. 88 p. 
  21. Trapeznikov A.V., Molchanova I.V., Karavaeva E.N., Trapeznikova V.N. Migratsiya radionuklidov v presnovodnykh ekosistemakh [The Radionuclide Migration in the Freshwater Ecosystems]. Yekaterinburg, 2007. 480 p.