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| Collins, James A.; Govin, A.; Mulitza, Stefan; Heslop, David; Zabel, M.; Hartmann, J.; Rohl, U.; Wefer, Gerold. |
| Relict dune fields that are found at 14° N in the modern-day African Sahel are testament to equatorward expansions of the Sahara desert during the late Pleistocene. However, difficulties of dating dune formation mean that abrupt millennial-scale climate events are not always resolved in these records. High-resolution marine core studies have identified Heinrich Stadials as the dustiest periods of the last glacial, although no studies have mapped the spatio-temporal evolution of dust export from West Africa. We use the major-element composition of four marine sediment cores to reconstruct the spatial extent of Saharan-dust versus river-sediment input to the continental margin from West Africa over the last 60 ka. This allows us to map the position of the... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00182/29279/27696.pdf |
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| Collins, J. A.; Govin, A.; Mulitza, S.; Heslop, D.; Zabel, M.; Hartmann, J.; Roehl, U.; Wefer, G.. |
| Relict dune fields that are found as far south as 14 N in the modern-day African Sahel are testament to equatorward expansions of the Sahara desert during the Late Pleistocene. However, the discontinuous nature of dune records means that abrupt millennial-timescale climate events are not always resolved. High-resolution marine core studies have identified Heinrich stadials as the dustiest periods of the last glacial in West Africa although the spatial evolution of dust export on millennial timescales has so far not been investigated. We use the major-element composition of four high-resolution marine sediment cores to reconstruct the spatial extent of Saharan-dust versus river-sediment input to the continental margin from West Africa over the last 60 ka.... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00181/29240/27635.pdf |
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| Govin, A.; Chiessi, C. M.; Zabel, M.; Sawakuchi, A. O.; Heslop, D.; Hoerner, T.; Zhang, Y.; Mulitza, S.. |
| We investigate changes in the delivery and oceanic transport of Amazon sediments related to terrestrial climate variations over the last 250 ka. We present high-resolution geochemical records from four marine sediment cores located between 5 and 12 degrees N along the northern South American margin. The Amazon River is the sole source of terrigenous material for sites at 5 and 9 degrees N, while the core at 12 degrees N receives a mixture of Amazon and Orinoco detrital particles. Using an endmember unmixing model, we estimated the relative proportions of Amazon Andean material ("%-Andes", at 5 and 9 degrees N) and of Amazon material ("%-Amazon", at 12 degrees N) within the terrigenous fraction. The %-Andes and %-Amazon records exhibit significant... |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40230/38675.pdf |
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