Uranium and thorium series isotopes in nearshore marine sediments [electronic resource].

Published: Washington, D.C. : United States. Dept. of Energy, 1980.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description: 11 pages : digital, PDF file
Additional Creators: United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information

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Summary

Measurements of U and Th series isotopes have been made on sediments most often as a means of estimating sediment accumulation rates. Therefore data are available for long half-life isotopes such as /sup 230/Th and /sup 231/Pa on slowly depositing deep-sea sediments, and for the short half-life isotopes such as /sup 228/Th, /sup 234/Th, and /sup 210/Pb mostly on rapidly accumulating coastal sediment. Studies of U and Th series nuclides in sediments of rivers entering the Gulf have been described in a previous section of this progress report. The isotopic decay series are out of equilibrium at several steps in the series. The activity ratio of /sup 234/U//sup 238/U is greater than 1 in sediment and water samples in a few cases, and the /sup 230/Th//sup 234/U ratio is greater than 1 in most instances. In the case of the Mississippi River suspended sediment, an average of 0.93 dpm/gm /sup 230/Th is present in excess of the amount of its parent /sup 234/U. This excess /sup 230/Th clearly must be added to the Gulf of Mexico by the river. The Gulf of Mexico sediments have been reported to have unusually high U concentrations. We have therefore begun a study of U, Th, Pa, Ra, and Pb isotopes in the sediments of this system, including the nearshore marine area of the Mississippi River Delta. The preliminary results are discussed in this report.

Report Numbers

E 1.99:oro-3852--38
oro-3852--38

Subject(s)

Note

Published through SciTech Connect.
01/01/1980.
"oro-3852--38"
Scott, M.R.; P. F. Salter.
Texas A and M Univ., College Station (United States). Research Foundation

Funding Information

AS05-76EV03852

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