Uranium and thorium series isotopes in nearshore marine sediments
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.
- Research Organization:
- Texas A and M Univ., College Station (United States). Research Foundation
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AS05-76EV03852
- OSTI ID:
- 5254177
- Report Number(s):
- ORO-3852--38
- Country of Publication:
- United States
- Language:
- English
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U-Th series nuclides in the Gulf of Mexico
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Related Subjects
Aquatic-- Radioactive Materials Monitoring & Transport-- Aquatic Ecosystems & Food Chains-- (-1987)
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
580400 -- Geochemistry-- (-1989)
ACTINIDES
ALKALINE EARTH METALS
ATLANTIC OCEAN
CARIBBEAN SEA
CHEMISTRY
COASTAL WATERS
DISTRIBUTION
ELEMENTS
ENVIRONMENTAL TRANSPORT
GEOCHEMISTRY
GULF OF MEXICO
ISOTOPE RATIO
ISOTOPES
LEAD
MASS TRANSFER
METALS
MISSISSIPPI RIVER
PROTACTINIUM
RADIOISOTOPES
RADIONUCLIDE MIGRATION
RADIUM
RIVERS
SEAS
SEDIMENTS
STREAMS
SURFACE WATERS
URANIUM