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Article Dans Une Revue Paleoceanography and Paleoclimatology Année : 2022

Evolution of Ocean circulation in the North Atlantic Ocean during the Miocene: impact of the Greenland ice sheet and the Eastern Tethys Seaway

Résumé

The Atlantic Meridional Overturning Circulation (AMOC) is today the central feature of the Global ocean circulation (Talley, 2013). It is dominated by two overturning cells usually referred to as the Antarctic Bottom Water (AABW) and the North Atlantic Deep Water (NADW). The NADW forms mainly in the Norwegian Sea by winter open-ocean cooling of salt-rich water advected northward by the Gulf Stream. The cooling increases the density of surface waters, which results in vertical convection and the formation of deep water. The newly formed deep and dense waters flow southward to the Southern Ocean, where they are upwelled under the action of the Antarctic Circumpolar Current (ACC). They are then dragged either into the AABW overturning branch and redistributed in the Pacific and Indian basins via the ACC or into the formation area of the Antarctic Intermediate Water (AAIW), thereby flowing northward as (sub)surface currents and closing the AMOC cell (Talley, 2013). The structure of the modern AMOC results from the particular configuration of the Atlantic basin geometry with a closed Central American Seaway and an open Drake Passage (Ferreira et al., 2018). During Cenozoic times (66-0 Ma) and, in particular, the Miocene period (23-5 Ma), the physical structure of the AMOC was probably different compared to the present-day because the configuration of major gateways and submarine topographic barriers in the Atlantic and Pacific basins differ substantially (Hutchinson et al., 2019). From the early Miocene (∼23 Ma) to today, these changes include the deepening of the Greenland-Scotland Ridge (Stärz et al., 2017), the opening of Fram Strait (Ehlers & Jokat, 2013) and Bering Strait (Gladenkov & Gladenkov, 2004) in the northern high latitudes; the closure of Central American Seaway (Montes et al., 2015) and Eastern Tethys Seaway (ETS, Bialik et al., 2019) in the tropics; and the potential narrowing of Drake Passage (Lagabrielle et al., 2009) in the southern high latitudes. Apart from those change in the seaways and the Eurasiatic landsea mask, the continental configuration during the Miocene period was close to the modern one with however some substantial changes in the topography worldwide such as lower elevation in major mountain belts (Andes, Himalayas, East Africa, and European ranges); see Poblete et al. (2021) for review.
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Dates et versions

hal-03763405 , version 1 (29-08-2022)

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Citer

Q. Pillot, Y. Donnadieu, A.‐C. Sarr, J.‐B. Ladant, B. Suchéras-Marx. Evolution of Ocean circulation in the North Atlantic Ocean during the Miocene: impact of the Greenland ice sheet and the Eastern Tethys Seaway. Paleoceanography and Paleoclimatology, 2022, 37 (8), pp.e2022PA004415. ⟨10.1029/2022pa004415⟩. ⟨hal-03763405⟩
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