226Ra in barite: Absolute dating of Holocene Southern Ocean sediments and reconstruction of sea-surface reservoir ages
- Pieter van Beek*1,
- Jean-Louis Reyss*1,
- Martine Paterne*1,
- Rainer Gersonde2,
- Michiel Rutgers van der Loeff2 and
- Gerhard Kuhn2
- 1Laboratoire des Sciences du Climat et de l'Environnement, Domaine du Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
- 2Alfred Wegener Institute for Polar and Marine Research, P.O. Box 120161, 27515 Bremerhaven, Germany
Abstract
Absolute dating of marine sediments is necessary to achieve reliable correlations of paleoclimate records. The 226Ra decay in barite separated from a deep-sea core of the Southern Ocean was used to determine absolute ages for the Holocene Epoch. Comparison with 14C ages measured on planktic foraminifers provides the first past sea-surface reservoir ages in the Antarctic zone of the Southern Ocean. Throughout the middle to late Holocene, our results indicate a reservoir age of ca. 1100 yr, comparable to modern estimates. A significantly higher reservoir age (ca. 1900 yr) is obtained for the early Holocene, which suggests a major change in the Southern Ocean circulation at that time.
Footnotes
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↵*E-mail addresses: van Beek—pvanbeeklsce.cnrs-gif.fr; Gersonde—rgersondeawi-bremerhaven.de
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↵GSA Data Repository item 2002084, Results obtained on samples separated from core PS2102-2, is available on request from Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, USA, editinggeosociety.org, or at www.geosociety.org/pubs/ft2002.htm.
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- Accepted April 18, 2002.
- Received January 12, 2002.
- Revision received April 18, 2002.
- Geological Society of America
