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| Blanchet, C. L.; Kasten, S.; Vidal, L.; Poulton, S. W.; Ganeshram, R.; Thouveny, N.. |
| In order to evaluate the influence of diagenetic and post-sampling processes on the stable oxygen and carbon isotope compositions of biogenic carbonates, we conducted a multiproxy study of organic-rich sediments from the eastern Pacific oxygen minimum zone. Core MD02-2520, which was retrieved from the Gulf of Tehuantepec (Mexico), has seasonal laminations and covers the last 40 kyr. Together with the presence of gypsum crystals and inorganic calcite aggregates, the occurrence of large excursions in the stable oxygen and carbon isotope records of both planktonic and benthic foraminifera (as large as +3 parts per thousand in delta O-18 and -5 parts per thousand in delta C-13) point to significant secondary transformations. Storage-related gypsum... |
| Tipo: Text |
Palavras-chave: Diagenesis; Gypsum; Inorganic calcite; Laminations; Oxygen minimum zone; Sulfur reoxidation. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00139/25049/23173.pdf |
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| Dumont, M.; Pichevin, L.; Geibert, W.; Crosta, X.; Michel, E.; Moreton, S.; Dobby, K.; Ganeshram, R.. |
| Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/72971/72036.pdf |
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