Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift
Growing interest in climate research and the coupled ocean-atmosphere interactions has led to numerous studies of the modern and ancient global ocean Thermohaline Circulation (THC). In the North Atlantic the Western Boundary Undercurrent (WBUC) forms the deep branch of the THC. The Eirik Drift, whic...
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ftawi:oai:epic.awi.de:32219 2023-05-15T16:00:42+02:00 Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift Mueller-Michaelis, Antje Uenzelmann-Neben, Gabriele 2013-03-04 https://epic.awi.de/id/eprint/32219/ https://hdl.handle.net/10013/epic.40853 unknown Mueller-Michaelis, A. and Uenzelmann-Neben, G. orcid:0000-0002-0115-5923 (2013) Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift , 73. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG), Helmholtz-Zentrum für Umweltforschung (UFZ) Leipzig, 4 March 2013 - 7 March 2013 . hdl:10013/epic.40853 EPIC373. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG), Helmholtz-Zentrum für Umweltforschung (UFZ) Leipzig, 2013-03-04-2013-03-07 Conference notRev 2013 ftawi 2021-12-24T15:38:20Z Growing interest in climate research and the coupled ocean-atmosphere interactions has led to numerous studies of the modern and ancient global ocean Thermohaline Circulation (THC). In the North Atlantic the Western Boundary Undercurrent (WBUC) forms the deep branch of the THC. The Eirik Drift, which lies on the slope south of Greenland, has been formed under the influence of this WBUC. The sediment record at the Eirik Drift thus documents changes in pathways and intensity of the WBUC and bears information about modifications of the North Atlantic THC in a changing climate. A study of the sedimentation history of the Eirik Drift will hence allow a deciphering of climate development and modifications in the Neogene. High resolution seismic reflection data collected during RV Maria S. Merian cruise MSM 12/2 were incorporated with geological information from ODP Leg 105 and IODP Expedition 303 Sites and led to a seismostratigraphic analysis of sedimentary structures. For the first time a detailed reconstruction of the palaeocirculation of the WBUC at the Eirik Drift since the Micoene is conducted. We date the onset of drift building under the influence of an intense WBUC at ~19 Ma. The WBUC remains strong from 19 to 10 Ma. Then it weakens and shallows gradually until 5.6 Ma. A separation of the WBUC into two branches at different core depths along with a renewed intensification is observed at 5.6 Ma. These two branches presumably transport Denmark Strait Overflow Water (lower branch) and Iceland Scotland Overflow Water (upper branch). The WBUC remains strong until ~2.5 Ma with a peak intensity at 4.5 Ma. We observe a gradual weakening and shallowing of the WBUC after 2.5 Ma. Thus, we observe a strong WBUC during warm phases (Miocene warm phase 20-15 Ma; Pliocene warm phase 5-3.6 Ma) as well as in the following cooling phases until pronounced ice-sheets are re-established (15-10 Ma; 3.6-2.75 Ma). The weakening of the WBUC takes place in the cooling phases after pronounced ice-sheets are re-established (10-5.6 Ma; < 2.5 Ma). Erosional unconformities are found at 19 Ma and 4.5 Ma close to the reversals of cooling to global warming phases (20 Ma and 5 Ma, respectively). The conjunction of warmer climate with an intensified NCW flow is ambiguous, as an intensified NCW circulation is a result of enhanced NCW production, which usually needs a colder environment. Conference Object Denmark Strait Greenland Iceland North Atlantic Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Greenland |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Growing interest in climate research and the coupled ocean-atmosphere interactions has led to numerous studies of the modern and ancient global ocean Thermohaline Circulation (THC). In the North Atlantic the Western Boundary Undercurrent (WBUC) forms the deep branch of the THC. The Eirik Drift, which lies on the slope south of Greenland, has been formed under the influence of this WBUC. The sediment record at the Eirik Drift thus documents changes in pathways and intensity of the WBUC and bears information about modifications of the North Atlantic THC in a changing climate. A study of the sedimentation history of the Eirik Drift will hence allow a deciphering of climate development and modifications in the Neogene. High resolution seismic reflection data collected during RV Maria S. Merian cruise MSM 12/2 were incorporated with geological information from ODP Leg 105 and IODP Expedition 303 Sites and led to a seismostratigraphic analysis of sedimentary structures. For the first time a detailed reconstruction of the palaeocirculation of the WBUC at the Eirik Drift since the Micoene is conducted. We date the onset of drift building under the influence of an intense WBUC at ~19 Ma. The WBUC remains strong from 19 to 10 Ma. Then it weakens and shallows gradually until 5.6 Ma. A separation of the WBUC into two branches at different core depths along with a renewed intensification is observed at 5.6 Ma. These two branches presumably transport Denmark Strait Overflow Water (lower branch) and Iceland Scotland Overflow Water (upper branch). The WBUC remains strong until ~2.5 Ma with a peak intensity at 4.5 Ma. We observe a gradual weakening and shallowing of the WBUC after 2.5 Ma. Thus, we observe a strong WBUC during warm phases (Miocene warm phase 20-15 Ma; Pliocene warm phase 5-3.6 Ma) as well as in the following cooling phases until pronounced ice-sheets are re-established (15-10 Ma; 3.6-2.75 Ma). The weakening of the WBUC takes place in the cooling phases after pronounced ice-sheets are re-established (10-5.6 Ma; < 2.5 Ma). Erosional unconformities are found at 19 Ma and 4.5 Ma close to the reversals of cooling to global warming phases (20 Ma and 5 Ma, respectively). The conjunction of warmer climate with an intensified NCW flow is ambiguous, as an intensified NCW circulation is a result of enhanced NCW production, which usually needs a colder environment. |
format |
Conference Object |
author |
Mueller-Michaelis, Antje Uenzelmann-Neben, Gabriele |
spellingShingle |
Mueller-Michaelis, Antje Uenzelmann-Neben, Gabriele Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
author_facet |
Mueller-Michaelis, Antje Uenzelmann-Neben, Gabriele |
author_sort |
Mueller-Michaelis, Antje |
title |
Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
title_short |
Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
title_full |
Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
title_fullStr |
Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
title_full_unstemmed |
Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift |
title_sort |
paleocirculation of the western boundary undercurrent (wbuc) at the eirik drift |
publishDate |
2013 |
url |
https://epic.awi.de/id/eprint/32219/ https://hdl.handle.net/10013/epic.40853 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Denmark Strait Greenland Iceland North Atlantic |
genre_facet |
Denmark Strait Greenland Iceland North Atlantic |
op_source |
EPIC373. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG), Helmholtz-Zentrum für Umweltforschung (UFZ) Leipzig, 2013-03-04-2013-03-07 |
op_relation |
Mueller-Michaelis, A. and Uenzelmann-Neben, G. orcid:0000-0002-0115-5923 (2013) Paleocirculation of the Western Boundary Undercurrent (WBUC) at the Eirik Drift , 73. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG), Helmholtz-Zentrum für Umweltforschung (UFZ) Leipzig, 4 March 2013 - 7 March 2013 . hdl:10013/epic.40853 |
_version_ |
1766396714894229504 |