Uranium and thorium distributions in fossil bones from Olduvai Gorge,Tanzania and Kanam,Kenya |
| |
| Institution: | 1. Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD, England;2. Department of Anthropology, University of Durham, Durham DH1 3HN, England;1. Universidade Federal do Piauí, CCN, Departamento de Física, Teresina, Piauí, Brazil;2. Universidade Federal do Piauí, Núcleo de Arqueologia e Paleontologia, Teresina, Piauí, Brazil;3. Universidade Federal do Cariri, Cidade Universitária, Juazeiro do Norte, Ceará, Brazil;4. Universidade Federal do Ceará, C.P. 6030, Departamento de Física, Fortaleza, Ceará, Brazil;5. Universidade Federal do Piaui, CCN, Pós Graduação em Ciências dos Materiais, Teresina, Piauí, Brazil;1. División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, CONICET, Paseo del Bosque s/n B1900FWA, La Plata, Argentina;2. Centro de Investigaciones Geológicas, CONICET, Universidad Nacional de La Plata, Diagonal 113 #275, B1904DPK, La Plata, Argentina;3. University of Vienna, Department of Palaeontology, Geocenter, Althanstrasse 14, 1090, Vienna, Austria;1. Vertebrate Zoology Department, Saint Petersburg State University, Saint Petersburg 199034, Russia;2. Saint Petersburg State Academy of Veterinary Medicine, Saint Petersburg 196084, Russia;1. Univ Rennes, CNRS, Géosciences Rennes, UMR CNRS 6118, Campus de Beaulieu, 263, avenue du Général Leclerc, F-35000 Rennes, France;2. 4, rue Saint-Just, F-17000 La Rochelle, France;3. Musée d’Angoulême, 1, rue Friedland, F-16000 Angoulême, France;4. 23A, rue des Barraudes, La Cotinière, F-17310 Saint-Pierre-d’Oléron, France;1. Laboratoire de Géologie de Lyon, UMR 5276 CNRS, ENS, Université Lyon 1, Campus de la Doua, Bt. Géode, 69622 Villeurbanne Cedex, France;2. Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements, UMR 7207 CNRS, MNHN, Université Pierre et Marie Curie Paris 6, Tour 46/56, 4 Place Jussieu, 75252 Paris Cedex 05, France;3. Muséum d''histoire naturelle, CP 6434, 1211 Genève 6, Switzerland;4. Unidad de Paleontología, Departamento de Biología, Universidad Autónoma de Madrid, c/ Darwin 2, Cantoblanco, 28049 Madrid, Spain |
| |
| Abstract: | The micro-distributions of uranium and thorium have been studied in fossil bone cortices in samples from Olduvai Gorge, Tanzania and Kanam, Kenya, and compared with modern bones collected from the surface at Olduvai Gorge. Concentrations in excess of 800 ppm U and 200 ppm Th are recorded in sections of some fossil bones, whereas concentrations do not exceed 20 ppm U or 1 ppm Th in the modern bones. In fossil bones, Th has a larger intra-bone variation than U. The distribution profiles of the two elements across the fossil bone cortices are quite distinct and reflect differences in their geochemical behaviour in the supergene environment. In particular, the two possible oxidation states of U, compared with one for Th, allow U to be more mobile than Th, but also more susceptible to variations in the redox potential of the depositional environment. In some fossil bone samples secondary leaching of U has occurred, whereas Th is retained in the bone cortex. U is incorporated into fossil bone earlier than Th. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
