Radiocarbon age offsets of foraminifera resulting from differential dissolution and fragmentation within the sedimentary bioturbated zone

Type Article
Date 2007-05
Language English
Author(s) Barker Stephen1, Broecker Wallace2, Clark Elizabeth2, Hajdas Irka3
Affiliation(s) 1 : Cardiff Univ, Sch Earth Ocean & Planetary Sci, Cardiff CF10 3YE, Wales.
2 : Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA.
3 : ETH Honggerberg, IPP, AMS Lab 14C, CH-8093 Zurich, Switzerland.
Source Paleoceanography (0883-8305) (Amer Geophysical Union), 2007-05 , Vol. 22 , N. 2/PA2205 , P. 1-11
DOI 10.1029/2006PA001354
WOS© Times Cited 49
Keyword(s) adiocarbon dating, dissolution, fragmentation
Abstract Shells of coexisting species of planktonic foraminifera from the Ontong Java Plateau reveal radiocarbon age offsets of up to 2200 years. Similar offsets are found between fragments and whole shells of single species. Steady state modelling of dissolution and bioturbation within the sedimentary mixed layer predicts age differences of up to several kiloyears due to the interplay between differential dissolution and fragmentation of foraminifer shells and bioturbation. The observation that fragile foraminiferal shells are systematically older than those of more robust species is more difficult to explain. Mechanisms of chemical erosion, interface dissolution, and sediment redistribution are all apparently unable to explain this phenomenon. A possible solution is presented in which a particular species may be represented by two distinct classes of shells which are more or less robust. In this case, differential dissolution and fragmentation causes an increase in the mean age as the fragile class contributes less to the remaining intact shells. This study highlights the vulnerability of low sedimentation rate cores to the effects of dissolution and bioturbation.
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Barker Stephen, Broecker Wallace, Clark Elizabeth, Hajdas Irka (2007). Radiocarbon age offsets of foraminifera resulting from differential dissolution and fragmentation within the sedimentary bioturbated zone. Paleoceanography, 22(2/PA2205), 1-11. Publisher's official version : https://doi.org/10.1029/2006PA001354 , Open Access version : https://archimer.ifremer.fr/doc/00238/34943/