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Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water

This study aims to provide a more detailed understanding of the behavior of 231Pa/230Th under varying ocean circulation regimes. The North Atlantic provides a unique sedimentary setting with its ice-rafted detritus (IRD) layers deposited during glacial times. These layers have been found north of 40...

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Main Authors: Süfke, Finn (Author) , Schulz, Hartmut (Author) , Scheen, Jeemijn (Author) , Szidat, Sönke (Author) , Regelous, Marcel (Author) , Blaser, Patrick (Author) , Pöppelmeier, Frerk (Author) , Goepfert, Tyler J. (Author) , Stocker, Thomas F. (Author) , Lippold, Jörg (Author)
Format: Article (Journal)
Language:English
Published: 07 January 2020
In: Geo-marine letters
Year: 2020, Volume: 40, Issue: 1, Pages: 75-87
ISSN:1432-1157
DOI:10.1007/s00367-019-00634-7
Online Access:Verlag, lizenzpflichtig, Volltext: https://dx.doi.org/10.1007/s00367-019-00634-7
Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1007/s00367-019-00634-7
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Author Notes:Finn Süfke, Hartmut Schulz, Jeemijn Scheen, Sönke Szidat, Marcel Regelous, Patrick Blaser, Frerk Pöppelmeier, Tyler J. Goepfert, Thomas F. Stocker, Jörg Lippold
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Summary:This study aims to provide a more detailed understanding of the behavior of 231Pa/230Th under varying ocean circulation regimes. The North Atlantic provides a unique sedimentary setting with its ice-rafted detritus (IRD) layers deposited during glacial times. These layers have been found north of 40° N (Ruddiman Belt) and are most pronounced during Heinrich Stadials. Most of these sediments have been recovered from the deep North Atlantic basin typically below 3000 m water depth. This study reports sedimentological and sediment geochemical data from one of the few sites at intermediate depth of the open North Atlantic (core SU90-I02, 45° N 39° W, 1965 m water depth) within the Ruddiman Belt. The time periods of Heinrich Stadials 1 and 2 of this core were identified with the help of the major element composition by XRF scanning and by IRD counting. Along the core profile, the sedimentary 231Pa/230Th activity ratio has been measured as a kinematic proxy for the circulation strength. The 231Pa/230Th record shows highest values during the Holocene and Last Glacial Maximum, above the natural production ratio of these isotopes. During Heinrich Stadials 1 and 2, when Atlantic meridional overturning circulation was most reduced, the 231Pa/230Th record shows overall lowest values below the production ratio. This behavior is contrary to classical findings of 231Pa/230Th from the northwestern Atlantic where a strong Holocene circulation is associated with low values. However, this behavior at the presented location is in agreement with results from simulations of the 231Pa/230Th-enabled Bern3D Earth system model.
Item Description:Im Titel sind "231" und "230" als Hochzahlen dargestellt
Gesehen am 26.10.2020
Physical Description:Online Resource
ISSN:1432-1157
DOI:10.1007/s00367-019-00634-7

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