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U.S. Department of Energy
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2. 05 x 10/sup 9/ age of the Oklo uranium deposit

Conference ·
OSTI ID:5157383
U and Pb isotopic data on samples (10 to 100 gram) 2 to 10 m away from the borders of the Oklo reactor zones indicate a primary age of 2.05 x 10/sup 9/ years for the Oklo deposit and a secondary age of 0.375 x 10/sup 9/ years. All samples show effects of Pb loss; the average loss is 50 percent. Both the U--Pb and Pb isotopic data are consistent with a model of a primary 2.05 x 10/sup 9/ year age of the deposit, continuous volume diffusion of Pb from uraninite, and either continuous or recent loss of this Pb. In this case the 0.375 x 10/sup 9/ year age is an artifact without time significance. Using an average value of D/a/sup 2/ 3.5 x 10/sup -11/ a/sup -1/ (Cowan, this conference) this model explains the apparent 1.8 x 10/sup 9/ year Pb age observed by other workers. From the /sup 208/Pb//sup 206/Pb data the average U/Th value calculated for the Oklo deposit is approximately 100.
Research Organization:
Los Alamos Scientific Lab., N.Mex. (USA)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
5157383
Report Number(s):
LA-UR-77-2872; CONF-771222-2
Country of Publication:
United States
Language:
English