 | Ndongo, Alexis, Guiraud, Michel, Vennin, Emmanuelle, Mbina, Michel, Buoncristiani, Jean-François, Thomazo, Christophe, Flotté, Nicolas (2016) Control of fluid-pressure on early deformation structures in the Paleoproterozoic extensional Franceville Basin (SE Gabon) Precambrian Research, 277. 1-25 doi:10.1016/j.precamres.2016.02.003 | Journal (article/letter/editorial) | | Paleoproterozoic extensional Franceville Basin (SE Gabon) Alexis Ndongo a , Michel Guiraud a,∗ , Emmanuelle...et Techniques de Masuku, B.P. 943, Franceville, Gabon c AREVA Mining Business Group Tour AREVA, 1 place...Well-preserved outcrops may be found in quarries (i.e. Oklo, Mikouloungou and Socoba) and along roads and railways’...fluid-pressure related structures. Synlithification faults in Oklo quarry and sand injectites at M’vengue underlined...and stylolites) close to synsedimentary faults at Oklo and Mikouloungou suggest a near-surface postlithification |  | | Journal (article/letter/editorial) | | in micro-minerals bearing fission products in the Oklo and Bangombé natural reactors: A review of a natural...migration of fission products H. Hidaka ∗ , M. Kikuchi Department of Earth and Planetary Systems Science, Hiroshima...Natural reactor Gabon Migration a b s t r a c t In the Precambrian, parts of the Oklo, Okélobondo and...Republic of Gabon, central Africa, functioned as natural fission reactors. Many elements in the Oklo and Bangombé...analyses on micro-minerals found in and around the Oklo and Bangombé natural reactors are reviewed in this |  | | Journal (article/letter/editorial) | | uraninite in the natural fission reactors in Gabon J. ‘Department JANECZEK’ and R. C. EWING’ ‘Faculty of...uranium ore from the natural fission reactors in Gabon were studied by detailed electron microprobe analysis...Ru. INTRODUCTION it has also been recognized at Oklo (Havette et al., 1975; Lancelot et al., 1975; Devillers...loss from uraninite, the U-P\, ages of U ore at Oklo range from 1780 Ma to 2050 Ma (Naudet, 1991). A...1993b). The major episode of Pb mobilization at Oklo has been related to the intrusion of a dolerite |  | Préat, Alain, Bouton, Pascal, Thiéblemont, Denis, Prian, Jean-Pierre, Ndounze, Serge Simo, Delpomdor, Franck (2011) Paleoproterozoic high δ13C dolomites from the Lastoursville and Franceville basins (SE Gabon): Stratigraphic and synsedimentary subsidence implications. Precambrian Research, 189 (1) 212-228 doi:10.1016/j.precamres.2011.05.013 | Journal (article/letter/editorial) | | from the Lastoursville and Franceville basins (SE Gabon): Stratigraphic and synsedimentary subsidence implications...Serge Simo Ndounze d , Franck Delpomdor a a Department of Earth Science and Environmental Sciences,...des Mines et de la Géologie, BP 284 Libreville, Gabon b a r t i c l e i n f o Article history: Received...Stable isotopes Paleoproterozoic Francevillian Group Gabon a b s t r a c t New data for the isotopic composition...shallow-marine sedimentary carbonates in southeastern Gabon (Franceville and Lastoursville sub-basins) indicate |  | Hidaka, Hiroshi, Janeczek, Janusz, Skomurski, Frances N., Ewing, Rodney C., Gauthier-Lafaye, François (2005) Geochemical fixation of rare earth elements into secondary minerals in sandstones beneath a natural fission reactor at Bangombé, Gabon. Geochimica et Cosmochimica Acta, 69 (3) 685-694 doi:10.1016/j.gca.2004.07.019 | Journal (article/letter/editorial) | | beneath a natural fission reactor at Bangombé, Gabon HIROSHI HIDAKA,1,2,* JANUSZ JANECZEK,3 FRANCES N...RODNEY C. EWING,4 and FRANÇOIS GAUTHIER-LAFAYE5 1 Department of Earth and Planetary Systems Science, Hiroshima...University, Higashi-Hiroshima 739-8526, Japan 3 Department of Earth Sciences, University of Silesia, ul... Bedzinska 60, PL-41-200 Sosnowiec, Poland 4 Department of Geological Sciences, University of Michigan...beneath a natural fission reactor at Bangombé, Gabon. Phosphate minerals such as phosphatian coffinite |  | Mathieu, Régis, Zetterström, Lena, Cuney, Michel, Gauthier-Lafaye, François, Hidaka, Hiroshi (2001) Alteration of monazite and zircon and lead migration as geochemical tracers of fluid paleocirculations around the Oklo–Okélobondo and Bangombé natural nuclear reaction zones (Franceville basin, Gabon) Chemical Geology, 171 (3) 147-171 doi:10.1016/s0009-2541(00)00245-x | Journal (article/letter/editorial) | | and zircon and lead migration as geochemical tracers of fluid paleocirculations around the Oklo–Okelobondo...natural nuclear reaction zones ´ žFranceville basin, Gabon/ Regis ´ Mathieu a,) , Lena Zetterstrom ¨ b, Michel...rue Blessig, Strasbourg Cedex F-67084, France ´ Department of Earth and Planetary Systems, Faculty of Science...sandstones of the Franceville basin ŽGabon. hosting Oklo natural nuclear reaction zones ŽRZ. in relation...uranium reserves from the Franceville basin. In zircon crystals, the cores are generally homogeneous, |  | | Journal (article/letter/editorial) | | recrystallization and Pb loss in the Oklo and Bangombé natural fission reactors, Gabon LENA Z. EVINS,1,* KELD A....Museum of Natural History, Stockholm, Sweden Department of Geological Sciences, University of Michigan...accepted in revised form July 19, 2004) Abstract—The Oklo and Bangombé natural fossil fission reactors formed...formed ca. 2 Ga ago in the Franceville basin, Gabon. The response of uraninite in the natural reactors...Uraninite and galena from two reactor zones, RZ16 at Oklo and RZB at Bangombé, were studied to clarify the |  | | Journal (article/letter/editorial) | | EOA3CO,Canada 21aboratory of Organic Geochemistry, Department of Geosciences, The University of Arizona, Tucson...kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium...to the 3 Ga old Witwatersrand and the 2.1 Ga old Oklo ore deposits. They have been regionally metamorphosed...uranium ores and natural fission reactors of Oklo, Republic of Gabon. Twenty-five maximum and minimum reflectance...some of the organic matter in the vicinity of the Oklo natural fission reactors ( NAGY et al., 199 1). |  | Kikuchi, M., Hidaka, H., Horie, K., Gauthier-Lafaye, F. (2007) Redistribution of REE, Pb and U by supergene weathering studied from in-situ isotopic analyses of the Bangombé natural reactor, Gabon. Geochimica et Cosmochimica Acta, 71 (19) 4716-4726 doi:10.1016/j.gca.2007.07.016 | Journal (article/letter/editorial) | | reactor, Gabon M. Kikuchi a, H. Hidaka a a,b,* , K. Horie a,c , F. Gauthier-Lafaye b Department of Earth...UMR7517-CNRS-ULP, 1 rue Blessig, 67084 Strasbourg, France c Department of Science and Engineering, National Science...shale layers above the Bangombé natural reactor, Gabon, were performed using a sensitive high-resolution...role in preventing fission products from spreading. Zircon crystals in the clays heterogeneously contain high-U...than reactor uraninite. The U–Pb systematics of zircon provide chronological information on the old igneous |  | | Journal (article/letter/editorial) | | reactors in Oklo were operating (Adam, 2007; Fig. 3). 3.2. Proterozoic natural nuclear reactor in Oklo, Gabon...uranium deposits of the Francevillian series in Gabon (Bodu et al., 1972; Neuilly et al., 1972). Since...reactor zones (RZs) have been found in the Oklo in Gabon, several of which are characterized in Table...within Okelobondo and Bangombe deposits close to Oklo (Hidaka and Kikuchi, 2010). The RZs consist of high-grade...2016). Summarizing the formation history of the Oklo natural reactors, detrital U-bearing minerals were |  | | Journal (article/letter/editorial) | | Kenji Horie a , Françoise Gauthier-Lafaye c a Department of Earth and Planetary Systems Science, Hiroshima...included in sandstone near the Oklo uranium deposit, Republic of Gabon, show extremely low 207Pb/206Pb... Keywords: radium; adsorption; illite; calcite; Oklo natural reactor; Pb isotopes 1. Introduction Radium...interest to understand the ⁎ Corresponding author. Department of Earth and Planetary Systems Science, Hiroshima...Fig. 1. (A) The location of reactor zone at the Oklo uranium deposit. (B) Cross section of gallery SD37 |  | | Report (chapter) | | 2015 Special cases of natural analogues: The Gabon and Cigar Lake U ore deposits F. G A U T H I E R... Tokai-mura, Ibaraki-ken, Japan Abstract: The Gabon and Cigar Lake uranium deposits may be used as natural...clay matrix. Futhermore, the Oklo and Bangomb6 uranium deposits in Gabon were natural nuclear fission...explain the preservation of the natural reactors of Gabon and of the Cigar Lake deposit. The mineralogy of...Cigar Lake deposit and in the natural reactors of Gabon. Coffinitization may be related to hydrothermal |  | | Journal (article/letter/editorial) | | Review A Review of In Situ Isotopic Studies of the Oklo and Bangombé Natural Fission Reactors Using Microbeam...Microbeam Analytical Techniques Hiroshi Hidaka Department of Earth and Planetary Sciences, Nagoya University...fission products, have been found in and around the Oklo and the Bangombé natural reactors. In the past two...compositions of various elements in and around the Oklo and Bangombé natural reactors vary significantly...like to review the isotopic results related to the Oklo and Bangombé reactors mainly based on my works using |  | | Journal (article/letter/editorial) | | chain reactions such as have been identified in Gabon, West Africa, has prompted a re-examination of very...preserved in uranium ore deposits at the Oklo mine in the Republic of Gabon, West Africa (Proceedings, 1975)...1975). In some samples of ore from this mine the 235U/238U atomic ratio, R, is as low as 0.374 compared to...rare, there is little reason to believe that the Oklo occurrences were unique. If similar reactors have...R have, in fact, been observed and, prior to the Oklo discovery, could be attributed entirely to isotope |  | | Journal (article/letter/editorial) | | Ma ago. The model explaining the formation of the Oklo uranium deposits suggests that at the time of sediment...Paleoproterozoic; Uranium; Manganese; Atmosphere; Oklo; Gabon; Carbon isotopes; Black shales 1. Introduction...Introduction The natural nuclear fission reactors in Gabon are unique. The possibility that nuclear fission reactions...occur 2.0 Ga ago in the Oklo uranium deposit of the Francevillian Series, Gabon (Neuilly et al., 1972)...in the Paleoproterozoic uranium ore deposits of Gabon. This observation raises the question whether this |  | | Journal (article/letter/editorial) | | fissiogenic platinum group elements in the Oklo natural reactor, Gabon Makiko Kikuchi a, Hiroshi Hidaka a,*...*, Francßois Gauthier-Lafaye b a Department of Earth and Planetary Systems Science, Hiroshima University...acid residue of SD37-S2/CD uraninite taken from Oklo natural reactor zone (RZ) 13. Quantitative analyses...Smellie, 1992). Among the natural analogues, the Oklo uranium de* Corresponding author. Tel.: +81 82 424...et al., 1972), 16 RZs have been identified in the Oklo uranium deposit and numbered in the chronological |  | Bankole, Olabode M., El Albani, Abderrazak, Meunier, Alain, Gauthier-Lafaye, François (2015) Textural and paleo-fluid flow control on diagenesis in the Paleoproterozoic Franceville Basin, South Eastern, Gabon. Precambrian Research, 268. 115-134 doi:10.1016/j.precamres.2015.07.008 | Journal (article/letter/editorial) | | Paleoproterozoic Franceville Basin, South Eastern, Gabon Olabode M. Bankole a,∗ , Abderrazak El Albani a...Basin Gabon a b s t r a c t The Paleoproterozoic (∼2.15 Ga) Franceville Basin, South Eastern Gabon, is...Franceville Basin (Fig. 1), located in south-eastern Gabon, represents one of the world oldest petroleum systems...2010, 2014) and natural nuclear fission reactors at Oklo, and widely explored for uranium and manganese ore...Regional geological map of Franceville Basin in Gabon (Ossa et al., 2013) that shows location of the study |  | | Journal (article/letter/editorial) | | fissiogenicREEs from a natural fission reactor at Bangomb6,Gabon hxusz JlNsczrrt .nxoRonNrv C. Ewrxc2 'Faculty of...monazite-(Ce),apatite, TiO, (probably anatase),zircon, and illite. Grains of florencite-(Ce)contain inclusions...deposits of the Franceville Basin in southeastern Gabon at approximately2 Ga andlasted 105-106yr, producinga...fission-reactor zones have been discovered in the U deposit at Oklo since 1972. Two more reactorsare known at Okelobondo...Okelobondo and Bangomb6, some 0.5 and 20 km south of Oklo, respectively. The Bangomb6 fission reactor, discovered |  | | Journal (article/letter/editorial) | | Branch Road NW, Washington, D.C. 20015, U.S.A. Department of Geological Sciences, University of Michigan...Avenue, Ann Arbor, Michigan 48109-1005, U.S.A. 3 Department of Earth and Planetary Sciences, Johns Hopkins...(Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport...abundances [e.g., ~3 metric tons (mT) of Pu at the Oklo natural reactors, 5 mT of Pu from atmospheric testing...where they were incorporated as minor elements in zircon (which can concentrate U relative to Th). Subsequent |  | | Journal (article/letter/editorial) | | the supercontinent Columbia? John J.W. Rogers* Department of Geological Sciences, University of North Carolina...system at various places worldwide, such as Oklo, Gabon, and may have caused the first lead isotope paradox...Introduction At 1.8 Ga pitchblende veins near Oklo, Gabon, went critical and underwent natural fission...The synchrony of the oldest orogenic belts and the Oklo reactor suggests that the cooling of the earth reached...studies of uranium veins near Oklo, Gabon. One of the principal observations at Oklo is that 235U constitutes |  | | Journal (article/letter/editorial) | | Deditius ⁎, Satoshi Utsunomiya 1, Rodney C. Ewing Department of Geological Sciences, University of Michigan...Deditius). 1 Current address. Kyushu University, Department of Chemistry, Ropponmatsu, 4-2-1, Chuou-ku, Fukuoka-shi...limited or complete solid solutions between: coffinite–zircon (ZrSiO4)–thorite (ThSiO4)– xenotime (YPO4)–ningyoite...composition of coffinite is from the U-deposits in Oklo, Gabon (e.g., Janeczek, 1999; Jensen and Ewing, 2001;...been reported in the natural reactor in Bangombé, Gabon, suggesting that coffinite may play an important |  | | Journal (article/letter/editorial) | | phases and bitumen in the Oklo Proterozoic natural fission reactors, Gabon JOHN PARNELL School of Geosciences...the Proterozoic natural fission reactors at Oklo, Gabon contain abundant organic matter (bitumen), with...bitumen, uranium, Oklo, Gabon. Introduction TllE uranium ore deposits at Oklo, Gabon, are unique in including...the migration and retention of elements about the Oklo reactors. Work on fissiogenic isotopes shows that....... i :ili~Libreville 0~ F GABON -::I" - 1 ,:.."" N 5~3 4 Oklo ;\ 2" "2-.... " 9 "2:.... |  | | Journal (article/letter/editorial) | | radiolysis on local redox conditions in the Oklo, Gabon, natural fission reactors 10 and 16 CREGU VI~RONIQIJE...significantly modify the local redox conditions. The Oklo natural fission zones are good examples where the...claimed that, in the conditions of the operating Oklo reactors, there had been the same recombination...matter was not considered in these calculations. The Oklo nuclear fission zones are excellent sites for studying...spectroscopy. r c Libreville c GABON 1 t r Q 500 m i OKLO \ - ’ _,.., . . . 6 Manganese 0 |  | | Journal (article/letter/editorial) | | os de Caldas, Cigar Lake, Maqarin, El Berrocal, Oklo and Palmottu. To make this comparison meaningful...primary uranium mineralisations (Enresa, 1996); Oklo (Gabon), a fossil natural nuclear reactor systems located...carried out to date. For example, the studies at Oklo and Palmottu were completed only during 1999. Consequently...BPM exercises, from the Pocß os de Caldas to the Oklo and Palmottu projects, has not varied significantly...(Spain), CSIC (Spain) and MBT/QuantiSci (Spain). Oklo: CEA (France), Ciemat (Spain), CNRS (France), CSIC |  | Rantzsch, Ulrike, Gauert, Christoph D. K., Van der Westhuizen, Willem A., Duhamel, Isabelle, Cuney, Michel, Beukes, Gerhard J. (2011) Mineral chemical study of U-bearing minerals from the Dominion Reefs, South Africa. Mineralium Deposita, 46 (2) 187-196 doi:10.1007/s00126-010-0317-4 | Journal (article/letter/editorial) | | sulfarsenides, garnet, pyrite, pyrrhotite, monazite, zircon, chromite, magnetite and minor gold. Sub-rounded...(*) : W. A. Van der Westhuizen : G. J. Beukes Department of Geology, University of the Free State, P.O...and Upper Reef) were mined underground at Rietkuil Mine by Uranium One Africa Ltd from 2006 to 2008. The...a 700–800 m thick volcanosedimentary unit in the mine area (Fig. 2), underlies the Witwatersrand Supergroup...Archean granitegreenstone basement at 3,120 ± 5 Ma (zircon U–Pb SHRIMP ages). Both Dominion conglomerate beds |
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