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| White, Lee F.; Bailey, Ian; Foster, Gavin L.; Allen, Georgina; Kelley, Simon P.; Andrews, John T.; Hogan, Kelly; Dowdeswell, Julian A.; Storey, Craig D.. |
| The provenance of sand-sized ice-rafted debris (IRD) sourced from Greenland is currently difficult to determine. Such knowledge, if it could be ascertained with a high degree of certainty, could be applied to the Greenland-proximal marine records to improve both our understanding of modern-day spatial patterns of iceberg rafting and the past history of the Greenland Ice Sheet (GIS). Recent studies have highlighted the utility of the Pb-isotope composition of individual sand-sized feldspars and the Ar-40/Ar-39 ages of individual sand-sized hornblendes in this regard. However, before any such provenance toolkit can be applied to the palaeo-record, it is necessary first to determine whether this approach can be used to track the sources of known recent... |
| Tipo: Text |
Palavras-chave: Greenland; Ice rafted debris; Ar-Ar; Pb isotopes; Icebergs; Provenance. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53292/54130.pdf |
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| Rae, James W. B.; Sarnthein, Michael; Foster, Gavin L.; Ridgwell, Andy; Grootes, Pieter M.; Elliott, Tim. |
| Deep water formation in the North Atlantic and Southern Ocean is widely thought to influence deglacial CO2 rise and climate change; here we suggest that deep water formation in the North Pacific may also play an important role. We present paired radiocarbon and boron isotope data from foraminifera from sediment core MD02-2489 at 3640m in the North East Pacific. These show a pronounced excursion during Heinrich Stadial 1, with benthic-planktic radiocarbon offsets dropping to similar to 350 years, accompanied by a decrease in benthic delta B-11. We suggest that this is driven by the onset of deep convection in the North Pacific, which mixes young shallow waters to depth, old deep waters to the surface, and low-pH water from intermediate depths into the deep... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40133/39114.pdf |
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| Gray, William R.; Rae, James W. B.; Wills, Robert C. J.; Shevenell, Amelia E.; Taylor, Ben; Burke, Andrea; Foster, Gavin L.; Lear, Caroline H.. |
| The interplay between ocean circulation and biological productivity affects atmospheric CO2 levels and marine oxygen concentrations. During the warming of the last deglaciation, the North Pacific experienced a peak in productivity and widespread hypoxia, with changes in circulation, iron supply and light limitation all proposed as potential drivers. Here we use the boronisotope composition of planktic foraminifera from a sediment core in the western North Pacific to reconstruct pH and dissolved CO2 concentrations from 24,000 to 8,000 years ago. We find that the productivity peak during the Bolling-Allerod warm interval, 14,700 to 12,900 years ago, was associated with a decrease in near-surface pH and an increase in pCO(2), and must therefore have been... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00496/60787/64968.pdf |
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