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This report investigates aberrantly high uranium contents occasionally developed in deep-sea sediments over the past 750 kyr. The systematics of radioactive ingrowth and decay on a known time-scale allow a prediction of expected uranium daughter activities for comparison with those observed. Such information is relevant to other actinides besides uranium, since all actinides decay through chains of the same radio-elements before achieving stability. The aim of the reported research was to determine uranium and its long-lived daughter radionuclides (specifically the isotopes 234U, 230Th, 226Ra, 210Po, and 231Pa) in selected turbidites with ages between 250 kyr and 750 kyr. The observed profiles are compared with those predicted by radioactive ingrowth systematics to determine whether diffusion of uranium daughter nuclides away from the peak areas has occurred. The experimental data are used to estimate effective diffusion coefficients of the different nuclides for modelling purposes. Such data are relevant to the in-situ geochemical conditions of the sediments over the long time scales involved.

Additional information

Authors: COLLEY S, Institute of Oceanographic Sciences, Godalming (GB);THOMSON J, Institute of Oceanographic Sciences, Godalming (GB)
Bibliographic Reference: EUR 13182 EN (1991) 92 pp., FS, ECU 8.75
Availability: (2)
ISBN: ISBN 92-826-2164-2
Record Number: 199110297 / Last updated on: 1994-12-02
Original language: en
Available languages: en