Ocean mixing and ice-sheet control of seawater 234U/238U during the last deglaciation
Chen, T.; Robinson, L.F.; Beasley, M.P.; Claxton, L.M.; Andersen, M.B.; Gregoire, L.J.; Wadham, J.; Fornari, D.J.; Harpp, K.S. (2016). Ocean mixing and ice-sheet control of seawater 234U/238U during the last deglaciation. Science (Wash.) 354(6312): 626-629. http://dx.doi.org/10.1126/science.aag1015
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075; e-ISSN 1095-9203, more
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| Authors | | Top |
- Chen, T.
- Robinson, L.F.
- Beasley, M.P.
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- Claxton, L.M.
- Andersen, M.B.
- Gregoire, L.J.
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- Wadham, J.
- Fornari, D.J.
- Harpp, K.S.
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| Abstract |
Seawater U-234/U-238 provides global-scale information about continental weathering and is vital for marine uranium-series geochronology. Existing evidence supports an increase in U-234/U-238 since the last glacial period, but the timing and amplitude of its variability has been poorly constrained. Here we report two seawater U-234/U-238 records based on well-preserved deep-sea corals from the low-latitude Atlantic and Pacific Oceans. The Atlantic U-234/U-238 started to increase before major sea-level rise and overshot the modern value by 3 per mil during the early deglaciation. Deglacial U-234/U-238 in the Pacific converged with that in the Atlantic after the abrupt resumption of Atlantic meridional overturning. We suggest that ocean mixing and early deglacial release of excess U-234 from enhanced subglacial melting of the Northern Hemisphere ice sheets have driven the observed U-234/U-238 evolution. |
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