Uranium contents and isotope ratios of uranium and strontium in sediments, leachates and pore fluids from ODP Hole 162-984A ...
Bulk dissolution rates for sediment from ODP Site 984A in the North Atlantic are determined using the 234U/238U activity ratios of pore water, bulk sediment, and leachates. Site 984A is one of only several sites where closely spaced pore water samples were obtained from the upper 60 meters of the co...
| Main Authors: | , , |
|---|---|
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
PANGAEA
2004
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.1594/pangaea.708717 https://doi.pangaea.de/10.1594/PANGAEA.708717 |
| Summary: | Bulk dissolution rates for sediment from ODP Site 984A in the North Atlantic are determined using the 234U/238U activity ratios of pore water, bulk sediment, and leachates. Site 984A is one of only several sites where closely spaced pore water samples were obtained from the upper 60 meters of the core; the sedimentation rate is high (11-15 cm/ka), hence the sediments in the upper 60 meters are less than 500 ka old. The sediment is clayey silt and composed mostly of detritus derived from Iceland with a significant component of biogenic carbonate (up to 30%).The pore water 234U/238U activity ratios are higher than seawater values, in the range of 1.2 to 1.6, while the bulk sediment 234U/238U activity ratios are close to 1.0. The 234U/238U of the pore water reflects a balance between the mineral dissolution rate and the supply rate of excess 234U to the pore fluid by a-recoil injection of 234Th. The fraction of 238U decays that result in a-recoil injection of 234U to pore fluid is estimated to be 0.10 to 0.20 ... : Supplement to: Maher, Katharine; DePaolo, Donald J; Lin, Jo Chiu-Fang (2004): Rates of silicate dissolution in deep-sea sediment; in situ measurement using 234U/238U of pore fluids. Geochimica et Cosmochimica Acta, 68(22), 4629-4648 ... |
|---|