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

• Verfasst von: Süfke, Finn [VerfasserIn]
• Verfasst von: Schulz, Hartmut [VerfasserIn]
• Verfasst von: Scheen, Jeemijn [VerfasserIn]
• Verfasst von: Szidat, Sönke [VerfasserIn]
• Verfasst von: Regelous, Marcel [VerfasserIn]
• Verfasst von: Blaser, Patrick [VerfasserIn]
• Verfasst von: Pöppelmeier, Frerk [VerfasserIn]
• Verfasst von: Goepfert, Tyler J. [VerfasserIn]
• Verfasst von: Stocker, Thomas F. [VerfasserIn]
• Verfasst von: Lippold, Jörg [VerfasserIn]
• Titel: Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water
• Verf.angabe: Finn Süfke, Hartmut Schulz, Jeemijn Scheen, Sönke Szidat, Marcel Regelous, Patrick Blaser, Frerk Pöppelmeier, Tyler J. Goepfert, Thomas F. Stocker, Jörg Lippold
• E-Jahr: 2020
• Jahr: 07 January 2020
• Umfang: 13 S.
• Fussnoten: Im Titel sind "231" und "230" als Hochzahlen dargestellt ; Gesehen am 26.10.2020
• Titel Quelle: Enthalten in: Geo-marine letters
• Ort Quelle: Berlin : Springer, 1984
• Jahr Quelle: 2020
• Band/Heft Quelle: 40(2020), 1, Seite 75-87
• ISSN Quelle: 1432-1157
• DOI: doi:10.1007/s00367-019-00634-7
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1736570099

Abstract

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.