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

Süfke F, Schulz H, Scheen J, Szidat S, Regelous M, Blaser P, Pöppelmeier F, Goepfert TJ, Stocker TF, Lippold J (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Geo-Marine Letters Springer Verlag (Germany)

DOI: 10.1007/s00367-019-00634-7

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.

Authors with CRIS profile

Marcel Regelous Geozentrum Nordbayern

Involved external institutions

Universität Bern CH Switzerland (CH) Ruprecht-Karls-Universität Heidelberg DE Germany (DE) Eberhard Karls Universität Tübingen DE Germany (DE) GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel DE Germany (DE)

How to cite

APA:

Süfke, F., Schulz, H., Scheen, J., Szidat, S., Regelous, M., Blaser, P.,... Lippold, J. (2020). Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water. Geo-Marine Letters. https://dx.doi.org/10.1007/s00367-019-00634-7

MLA:

Süfke, Finn, et al. "Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water." Geo-Marine Letters (2020).

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