Home Oxygen isotopic composition of nano-scale uraninite at the Oklo-Okélobondo natural fission reactors, Gabon
Article
Licensed
Unlicensed Requires Authentication

Oxygen isotopic composition of nano-scale uraninite at the Oklo-Okélobondo natural fission reactors, Gabon

  • Mostafa Fayek EMAIL logo , Satoshi Utsunomiya , Rodney C. Ewing , Lee R. Riciputi and Keld A. Jensen
Published/Copyright: March 31, 2015
Become an author with De Gruyter Brill

Abstract

High spatial resolution (10-30 μm), in situ oxygen isotopic analyses by secondary ion mass spectrometry (SIMS), coupled with high-resolution transmission electron microscopy (HRTEM), were used to show that uraninite from the Oklo-Okélobondo natural fission reactors that occur in near surface environments, have low δ18O values and nanotextures that are consistent with interaction with ground water. These low δ18O values (-14.4 to -8.5‰) suggest that the minerals exchanged with meteoric groundwater. In contrast, reactor zones that occur at depth have largely retained their original O isotopic composition (-10.2 to -5.6‰) and uraninites are well-crystallized and essentially defect-free. These observations clearly demonstrate that by combining both HRTEM and in situ O isotopic analyses by SIMS, it is possible to characterize the nano-scale porosity and postdepositional alteration of U-bearing phases.

Received: 2003-1-13
Accepted: 2003-6-8
Published Online: 2015-3-31
Published in Print: 2003-10-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Structural systematics of hydrous ringwoodite and water in earth’s interior
  2. Compressibility of phase Egg AlSiO3OH: Equation of state and role of water at high pressure
  3. Synchrotron infrared spectroscopy of OH-chondrodite and OH-clinohumite at high pressure
  4. Structural deformation mechanisms of zeolites under pressure
  5. Variation of hydrogen bonded O···O distances in goethite at high pressure
  6. Pressure-controlled polytypism in hydrous layered materials
  7. OH– in synthetic and natural coesite
  8. Pressure-induced phase transformation of kalicinite (KHCO3) at 2.8 GPa and local structural changes around hydrogen atoms
  9. Potential docking sites and positions of hydrogen in high-pressure silicates
  10. Contrasting bonding behavior of two hydroxyl-bearing metamorphic minerals under pressure: Clinozoisite and topaz
  11. Experimental investigation of crystallization kinetics in a haplogranite system
  12. Assessment of cation substitutions along the gallium and fluorine analogue of the tremolite-glaucophane join
  13. Experimental hydrothermal alteration of partially metamict zircon
  14. On the origin of size-dependent and size-independent crystal growth: Influence of advection and diffusion
  15. Ordering in spinels—A Monte Carlo study
  16. Single-crystal in situ high-temperature structural investigation of the I1̅ –I2/c phase transition in Ca0.2Sr0.8Al2Si2O8 feldspar
  17. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho
  18. Fe and Ni impurities in synthetic diamond
  19. Phase transformations and reaction kinetics during the temperature-induced oxidation of natural olivine
  20. Thermal infrared spectroscopy and modeling of experimentally shocked plagioclase feldspars
  21. Oxygen isotopic composition of nano-scale uraninite at the Oklo-Okélobondo natural fission reactors, Gabon
  22. Clinopyroxenite from the Sulu ultrahigh-pressure terrane, eastern China: Origin and evolution of garnet exsolution in clinopyroxene
  23. Letters. An assessment of nuclear microprobe analyses of B in silicate minerals
  24. Incommensurate phase in the kosmochlor-diopside join: A new polymorph of clinopyroxene
  25. Elastic properties of hydrous ringwoodite
  26. Thermochemistry of guest-free melanophlogite
  27. A simple model for the pressure preservation index of inclusions in diamond
Downloaded on 9.9.2025 from https://www.degruyterbrill.com/document/doi/10.2138/am-2003-1021/html
Scroll to top button