Role of organic matter in the Proterozoic Oklo natural fission reactors, Gabon, Africa
- Univ. of Arizona, Tucson (United States)
- Centre de Geochemie de la Surface, Strasbourg (France)
- Centre d`Etudes Nucleaires de Cadarache (France)
- Mount Allison Univ., Sackville, New Brunswick (Canada)
- Geological Survey, Denver, CO (United States)
Of the sixteen known Oklo and the Bangombe natural fission reactors (hydrothermally altered elastic sedimentary rocks that contain abundant uraninite and authigenic clay minerals), reactors 1 to 6 at Oklo contain only traces of organic matter, but the others are rich in organic substances. Reactors 7 to 9 are the subjects of this study. These organic-rich reactors may serve as time-tested analogues for anthropogenic nuclear-waste containment strategies. Organic matter helped to concentrate quantities of uranium sufficient to initiate the nuclear chain reactions. Liquid bitumen was generated from organic matter by hydrothermal reactions during nuclear criticality. The bitumen soon became a solid, consisting of polycyclic aromatic hydrocarbons and an intimate mixture of cryptocrystalline graphite, which enclosed and immobilized uraninite and the fission-generated isotopes entrapped in uraninite. This mechanism prevented major loss of uranium and fission products from the natural nuclear reactors for 1.2 b.y. 24 refs., 4 figs.
- OSTI ID:
- 140074
- Journal Information:
- Geology, Vol. 21, Issue 7; Other Information: PBD: Jul 1993
- Country of Publication:
- United States
- Language:
- English
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