Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ
Large river systems draining the West African Monsoon area deliver sediments and dissolved trace elements into the Gulf of Guinea (GoG) in the easternmost equatorial Atlantic. The different catchment areas of these river systems are characterized by different geological ages and rock types releasing...
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ftoceanrep:oai:oceanrep.geomar.de:19935 2023-05-15T14:00:49+02:00 Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ Kraft, Steffanie Weldeab, Syee Hathorne, Ed Frank, Martin 2012 https://oceanrep.geomar.de/id/eprint/19935/ unknown Kraft, S., Weldeab, S., Hathorne, E. and Frank, M. (2012) Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ. [Talk] In: Goldschmidt Conference 2012. , 24.-29.06.2012, Montreal, Canada . info:eu-repo/semantics/closedAccess Conference or Workshop Item NonPeerReviewed 2012 ftoceanrep 2023-04-07T15:07:20Z Large river systems draining the West African Monsoon area deliver sediments and dissolved trace elements into the Gulf of Guinea (GoG) in the easternmost equatorial Atlantic. The different catchment areas of these river systems are characterized by different geological ages and rock types releasing distinct radiogenic neodymium isotope compositions during weathering which are supplied to the GoG. The main rivers discharging into the GoG are the Niger, the Sanaga, the Nyong and the Ntem with present day εNd signatures of -10.5 [1], -12.3, -12.5 and -28.1 [2], respectively. These riverine inputs mix with the tropical Atlantic surface waters. At intermediate water depths Antarctic Intermediate Water (AAIW) prevails whereas the deep basin at this location is mainly filled with NADW. We focus on a marine sediment core that was recovered off the Sanaga and Ntem Rivers and we reconstruct changes in riverine inputs and in mixing of surface and deep water masses over the past 140,000 years. Changes in riverine inputs most likely reflecting latitudinal shifts of the rainfall zones across the different catchment areas were obtained from the Nd isotope signatures of the residual detrital fraction of the sediment. Sediment leachates of several GoG core top samples reflect the riverine input from nearby rivers indicating transport of particles coated in the rivers. Both the sediment leachates and the residual detrital fraction show similar patterns, with shifts towards radiogenic values during the interglacials and least radiogenic values during glacial periods. This shift in εNd values may be attributed to the migration of the rainfall zones towards the north during interglacial times and thus implies the increased influence of the northern rivers, the Sanaga and Nyong. The oxidatively-reductively cleaned planktonic foraminiferal calcite of the core top samples in the GoG reflects surface seawater signatures. Non-reductively cleaned planktonic foraminiferal tests and cleaned shallow endo-benthic and epi-benthic ... Conference Object Antarc* Antarctic NADW OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
unknown |
description |
Large river systems draining the West African Monsoon area deliver sediments and dissolved trace elements into the Gulf of Guinea (GoG) in the easternmost equatorial Atlantic. The different catchment areas of these river systems are characterized by different geological ages and rock types releasing distinct radiogenic neodymium isotope compositions during weathering which are supplied to the GoG. The main rivers discharging into the GoG are the Niger, the Sanaga, the Nyong and the Ntem with present day εNd signatures of -10.5 [1], -12.3, -12.5 and -28.1 [2], respectively. These riverine inputs mix with the tropical Atlantic surface waters. At intermediate water depths Antarctic Intermediate Water (AAIW) prevails whereas the deep basin at this location is mainly filled with NADW. We focus on a marine sediment core that was recovered off the Sanaga and Ntem Rivers and we reconstruct changes in riverine inputs and in mixing of surface and deep water masses over the past 140,000 years. Changes in riverine inputs most likely reflecting latitudinal shifts of the rainfall zones across the different catchment areas were obtained from the Nd isotope signatures of the residual detrital fraction of the sediment. Sediment leachates of several GoG core top samples reflect the riverine input from nearby rivers indicating transport of particles coated in the rivers. Both the sediment leachates and the residual detrital fraction show similar patterns, with shifts towards radiogenic values during the interglacials and least radiogenic values during glacial periods. This shift in εNd values may be attributed to the migration of the rainfall zones towards the north during interglacial times and thus implies the increased influence of the northern rivers, the Sanaga and Nyong. The oxidatively-reductively cleaned planktonic foraminiferal calcite of the core top samples in the GoG reflects surface seawater signatures. Non-reductively cleaned planktonic foraminiferal tests and cleaned shallow endo-benthic and epi-benthic ... |
format |
Conference Object |
author |
Kraft, Steffanie Weldeab, Syee Hathorne, Ed Frank, Martin |
spellingShingle |
Kraft, Steffanie Weldeab, Syee Hathorne, Ed Frank, Martin Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
author_facet |
Kraft, Steffanie Weldeab, Syee Hathorne, Ed Frank, Martin |
author_sort |
Kraft, Steffanie |
title |
Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
title_short |
Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
title_full |
Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
title_fullStr |
Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
title_full_unstemmed |
Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ |
title_sort |
past changes in riverine input in the gulf of guinea - linked to the migration of the itcz |
publishDate |
2012 |
url |
https://oceanrep.geomar.de/id/eprint/19935/ |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic NADW |
genre_facet |
Antarc* Antarctic NADW |
op_relation |
Kraft, S., Weldeab, S., Hathorne, E. and Frank, M. (2012) Past changes in riverine input in the Gulf of Guinea - linked to the migration of the ITCZ. [Talk] In: Goldschmidt Conference 2012. , 24.-29.06.2012, Montreal, Canada . |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1766270167633887232 |