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| Friedrich, T.; Timmermann, A.; Stichel, T.; Pahnke, K.. |
| Over the past decade, records of the seawater neodymium isotopic composition (epsilon(Nd)) have become a widely used proxy to reconstruct changes in ocean circulation. Our study investigates the transient response of epsilon(Nd) to large-scale ocean circulation changes using an Earth system model of intermediate complexity. It is shown that a weakening of the North Atlantic Deep Water formation results in positive epsilon(Nd) anomalies in the Atlantic and the Pacific below 1000m water depth whereas variations in Antarctic Bottom Water production generate a Pacific-Atlantic dipole pattern of deep ocean epsilon(Nd) changes. Further experiments explore which ocean regions are suitable to record the temporal evolution of the overturning in the North Atlantic... |
| Tipo: Text |
Palavras-chave: Neodymium; Ocean circulation; Meridional overturning; Ocean modeling; Reconstruction. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40055/39405.pdf |
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| Ronge, T. A.; Tiedemann, R.; Lamy, F.; Koehler, P.; Alloway, B. V.; De Pol-holz, R.; Pahnke, K.; Southon, J.; Wacker, L.. |
| During the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (Delta C-14) suggest the release of C-14-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this C-14-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores retrieved along a South Pacific transect to reconstruct the spatio-temporal evolution of Delta C-14 over the last 30,000 years. In similar to 2,500-3,600 m water depth, we find C-14-depleted deep waters with a maximum glacial offset to atmospheric (14)(C) (Delta Delta C-14 = -1,000%). Using a box model, we test the hypothesis that these low values might have been caused by an interaction of aging and... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53251/54716.pdf |
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