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| Broecker, Wallace; Clark, Elizabeth; Barker, Stephen; Hajdas, Irena; Bonani, Georges; Moreno, Eva. |
| Radiocarbon age differences for pairs of coexisting late glacial age benthic and planktic foraminifera shells handpicked from 10 sediment samples from a core from a depth of 2.8 km in the western equatorial Pacific are not significantly different from that of 1600 years calculated from measurements on prenuclear seawater. This places a lower limit on the depth of the interface for the hypothetical radiocarbon-depleted glacial age seawater reservoir required to explain the 190% drop in the (14)C/C for atmospheric CO(2), which occurred during the mystery interval (17.5 to 14.5 calendar years ago). These measurements restrict the volume of this reservoir to be no more than 35% that of the ocean. Further, (14)C measurements on a single Last Glacial Maximum age... |
| Tipo: Text |
Palavras-chave: Ocean circulation; Mystery interval; Radiocarbon dating. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00233/34449/32884.pdf |
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| Barker, Stephen; Broecker, Wallace; Clark, Elizabeth; Hajdas, Irka. |
| Shells of coexisting species of planktonic foraminifera from the Ontong Java Plateau reveal radiocarbon age offsets of up to 2200 years. Similar offsets are found between fragments and whole shells of single species. Steady state modelling of dissolution and bioturbation within the sedimentary mixed layer predicts age differences of up to several kiloyears due to the interplay between differential dissolution and fragmentation of foraminifer shells and bioturbation. The observation that fragile foraminiferal shells are systematically older than those of more robust species is more difficult to explain. Mechanisms of chemical erosion, interface dissolution, and sediment redistribution are all apparently unable to explain this phenomenon. A possible solution... |
| Tipo: Text |
Palavras-chave: Adiocarbon dating; Dissolution; Fragmentation. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00238/34943/33247.pdf |
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