Show simple item record

dc.contributor.authorBrown, Louise
dc.contributor.authorCook, Gordon T.
dc.contributor.authorMacKenzie, Angus B.
dc.contributor.authorThomson, John
dc.date.accessioned2021-02-11T21:32:40Z
dc.date.available2021-02-11T21:32:40Z
dc.date.issued2001-01-01
dc.identifier.citationBrown, L., Cook, G. T., MacKenzie, A. B., & Thomson, J. (2001). Radiocarbon age profiles and size dependency of mixing in northeast Atlantic sediments. Radiocarbon, 43(2B), 929-937.
dc.identifier.issn0033-8222
dc.identifier.doi10.1017/S003382220004159X
dc.identifier.urihttp://hdl.handle.net/10150/654568
dc.descriptionFrom the 17th International Radiocarbon Conference held in Jerusalem, Israel, June 18-23, 2000.
dc.description.abstractIn recent years, the most common technique for radiocarbon dating of deep-ocean sediments has been accelerator mass spectrometry (AMS) analysis of hand-picked planktonic forminifera (forams). Some studies have exposed age offsets between different sediment size fractions from the same depth within a core and this has important implications when establishing a chronological framework for palaeoceanographic records associated with a particular sediment component. The mechanisms generating the age offsets are not fully understood, a problem compounded by the fact that the fraction defined as "large"varies between different studies. To explore this problem, we dated samples of hand-picked forams from two Biogeochemical Ocean Flux Study (BOFS) cores, for which the presence of an offset between the bulk carbonate and >150 micrometers foraminiferal calcite had already been demonstrated. The presence of a constant age offset between bulk carbonate and coarse fraction material at the two BOFS sites has been confirmed, but the magnitude of the offset is dependent on whether a simple size-separation technique or hand-picking of well-preserved forams is applied. This may be explained if the selection of well preserved forams biases the sample towards those specimens that have spent least time in the surface mixed layer (SML) or have undergone less size selective mixing. Modeling of the 14C profiles demonstrates that SML depth and sediment accumulation rates are the same for both the bulk and coarse sediment fractions, which is consistent with the hypothesis that size-selective mixing is responsible for the age offset.
dc.language.isoen
dc.publisherDepartment of Geosciences, The University of Arizona
dc.relation.urlhttp://radiocarbon.webhost.uits.arizona.edu/
dc.rightsCopyright © by the Arizona Board of Regents on behalf of the University of Arizona. All rights reserved.
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectpaleo oceanography
dc.subjectNortheast Atlantic
dc.subjectmixing
dc.subjectplanktonic taxa
dc.subjecttextures
dc.subjectmarine sedimentation
dc.subjectsize distribution
dc.subjectbioclastic sedimentation
dc.subjectgrain size
dc.subjectaccelerator mass spectra
dc.subjectcores
dc.subjectAtlantic Ocean
dc.subjectNorth Atlantic
dc.subjectsedimentation
dc.subjectmarine sediments
dc.subjectForaminifera
dc.subjectProtista
dc.subjectmass spectra
dc.subjectspectra
dc.subjectHolocene
dc.subjectmicrofossils
dc.subjectsediments
dc.subjectCenozoic
dc.subjectQuaternary
dc.subjectC 14
dc.subjectcarbon
dc.subjectdates
dc.subjectisotopes
dc.subjectradioactive isotopes
dc.subjectInvertebrata
dc.subjectabsolute age
dc.titleRadiocarbon Age Profiles and Size Dependency of Mixing in Northeast Atlantic Sediments
dc.typeProceedings
dc.typetext
dc.identifier.journalRadiocarbon
dc.description.collectioninformationThe Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume43
dc.source.issue2B
dc.source.beginpage929
dc.source.endpage937
refterms.dateFOA2021-02-11T21:32:40Z


Files in this item

Thumbnail
Name:
3925-3596-1-PB.pdf
Size:
822.8Kb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record