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Geology of Ore Deposits

, Volume 56, Issue 5, pp 315–321 | Cite as

Fractionation factor of 238U and 235U isotopes in the process of hydrothermal pitchblende formation: A numerical estimate

  • I. V. Chernyshev
  • E. O. DubininaEmail author
  • V. N. Golubev
Article

Abstract

Owing to the rapid increase in available data on the natural variations of the 238U/235U ratio, new isotopic geochemical mark of redox processes are beginning to emerge. In this connection, numerical estimates of the 238U and 235U fractionation factor (α(UIV−UVI)) accompanying the reduction UVI → UIV are needed. Such an estimate has been obtained for hydrothermal pitchblende formation based on results of high-precision (±0.06‰) measurements of the 238U/235U ratio in local microsamples of coarse spherulitic pitchblende from carbonate-pitchblende veins at the Oktyabr’sky deposit (Strel’tsovsky uranium ore field, eastern Transbaikal region). For this purpose, we used the formation temperature of hydrothermal pitchblende and a maximum estimate of the fractionation factor for 238U and 235U isotopes in the solution-solid phase system under normal (25°C) conditions (Murphy et al., 2014). The most probable isotopic fractionation factor accompanying pitchblende crystallization from hydrothermal solution at T = 320−250°C falls into the interval α(UIV−UVI) = 1.00020−1.00023.

Keywords

Uranium Fractionation Factor Uranium Deposit 235U Ratio 235U Isotope 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Pleiades Publishing, Ltd. 2014

Authors and Affiliations

  • I. V. Chernyshev
    • 1
  • E. O. Dubinina
    • 1
    Email author
  • V. N. Golubev
    • 1
  1. 1.Institute of Geology of Ore Deposits, Petrography, Mineralogy, and GeochemistryRussian Academy of SciencesMoscowRussia

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