Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-25T08:02:18.421Z Has data issue: false hasContentIssue false
  • English
  • Français

Radiocarbon Age Offsets in Different-Sized Carbonate Components of Deep-Sea Sediments

Published online by Cambridge University Press:  18 July 2016

John Thomson ,
G. T. Cook ,
Robert Anderson ,
A. B. MacKenzie ,
D. D. Harkness  and
I.N. McCave
John Thomson
Affiliation:
Institute of Oceanographic Sciences Deacon Laboratory, Brook Road, Wormley, Godalming, Surrey, GU8 5UB, England
G. T. Cook
Affiliation:
Scottish Universities Research and Reactor Centre, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, Scotland
Robert Anderson
Affiliation:
Scottish Universities Research and Reactor Centre, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, Scotland
A. B. MacKenzie
Affiliation:
Scottish Universities Research and Reactor Centre, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, Scotland
D. D. Harkness
Affiliation:
NERC Radiocarbon Laboratory, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, Scotland
I.N. McCave
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, England
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We compared accelerator mass spectrometry (AMS) 14C ages of large (>150 μm) pelagic foraminifera with radiometric bulk carbonate 14C ages in two northeastern Atlantic cores. The foraminiferal ages are consistently older than those of the bulk sediment (by + 0.76 ka in Core 11881 and by + 1.1 ka in Core 11886), whereas corresponding fine (<5 μm) fraction ages are similar to those of the bulk sediment carbonate. We calculated near-identical sediment accumulation rates from both the foraminiferal and bulk sediment age/depth relations (3.0 cm ka−1 in Core 11881 and 5.9 cm ka−1 in Core 11886). Consideration of various factors that might produce such offsets leads us to believe that they are not artifacts, but were most probably caused by differential bioturbation of the different size-fractions in the sediment surface mixed layer. The importance of this finding is that many paleoceanographic records, such as the oxygen isotope record, also derive from analyses of large foraminifera, so that these records must be offset in time from the bulk of the sediments that they characterize.

Type
I. 14C in the Reconstruction of Past Environments
Information
Radiocarbon , Volume 37 , Issue 2 , 1995 , pp. 91 - 101
Copyright
Copyright © the Department of Geosciences, The University of Arizona 

References

Alter, R. C. and DeMaster, D. J. 1984 Estimates of particle flux and reworking at the deep-sea floor using 234Th/238U disequilibrium. Earth and Planetary Science Letters 67: 308–318.Google Scholar
Balsam, W. L. and McCoy, F. W. Jr. 1987 Atlantic sediments: Glacial/interglacial comparisons. Paleoceanography 2: 531–542.CrossRefGoogle Scholar
Bard, E., Arnold, M., Duprat, J., Moyes, J. and Duplessy, J.-C. 1987 Reconstruction of the last deglaciation: Deconvolved records of δ18O profiles, micropalaeonto-logical variations and mass spectrometric 14C dating. Climate Dynamics 1: 101–112.CrossRefGoogle Scholar
Boudreau, B. P. 1986a Mathematics of tracer mixing in sediments: 1. Spatially dependent, diffusive mixing. American Journal of Science 286: 161–198.CrossRefGoogle Scholar
Boudreau, B. P. 1986b Mathematics of tracer mixing in sediments: 2. Non-local mixing and biological conveyor belt phenomena. American Journal of Science 286: 199–238.CrossRefGoogle Scholar
Broecker, W. S., Andrée, M., Wölfli, W., Oeschger, H., Bonani, G. Kennett, J. and Peteet, D. 1988a The chronology of the last deglaciation: Implications to the cause of the Younger Dryas event. Paleoceanography 3: 1–19.CrossRefGoogle Scholar
Broecker, W. S., Andrée, M., Bonani, G., Wölfli, W., Oeschger, H., Klas, M., Mix, A. and Curry, W. 1988b Preliminary estimates for the radiocarbon age of deep water in the glacial ocean. Paleoceanography 3: 659–670.CrossRefGoogle Scholar
Cochran, J. K. 1985 Particle mixing rates in sediments of the eastern equatorial Pacific: Evidence from 210Pb, 239,240Pu and 137Cs distributions at MANOP sites. Geochimica et Cosmochimica Acta 49: 1195–1210.CrossRefGoogle Scholar
DeMaster, D. J. and Cochran, J. K. 1982 Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles. Earth and Planetary Science Letters 61: 257–281.CrossRefGoogle Scholar
Duplessy, J.-C., Arnold, M., Maurice, P., Bard, E., Duprat, J. and Moyes, J. 1986 Direct dating of the oxygen-isotope record of the last deglaciation by 14C accelerator mass spectrometry. Nature 320: 350–352.CrossRefGoogle Scholar
Eglinton, G., Bradshaw, S. A., Rosell, A., Sarnthein, M., Pflaumann, U. and Tiedemann, R. 1992 Molecular record of secular sea surface temperature changes on 100-year timescales for glacial terminations I, II and IV. Nature 356: 423–426.CrossRefGoogle Scholar
Erlenkeuser, H. 1980 14C age and vertical mixing of deep-sea sediments. Earth and Planetary Science Letters 47: 319–326.CrossRefGoogle Scholar
Jansen, E. and Veum, T. 1990 Evidence for two-step deglaciation and its impact on North Atlantic deep-water circulation. Nature 343: 612–616.CrossRefGoogle Scholar
Jones, G. A., Jull, A. J. T., Linick, T. W. and Donahue, D. J. 1989 Radiocarbon dating of deep-sea sediments: A comparison of accelerator mass spectrometer and beta-decay methods. Radiocarbon 31(2): 105–116.CrossRefGoogle Scholar
Kidd, R. B. and Hill, P. R. 1986 Sedimentation on mid-ocean sediment drifts. In Summerhayes, C. P. and Shackleton, N. J., eds., North Atlantic Palaeoceanography. Geological Society of London Special Publication 21: 87–102.CrossRefGoogle Scholar
McCave, I. N. 1988 Biological pumping upwards of the coarse fraction of deep-sea sediments. Journal of Sedimentary Petrology 58: 148–158.CrossRefGoogle Scholar
Nozaki, Y., Cochran, J. K., Turekian, K. K. and Keller, G. 1977 Radiocarbon and 210Pb distribution in submersible-taken deep-sea cores from Project FAMOUS. Earth and Planetary Science Letters 34:167–173.CrossRefGoogle Scholar
Officer, C. B. 1982 Mixing, sedimentation rates and age dating for sediment cores. Marine Geology 46: 261–278.CrossRefGoogle Scholar
Oxburgh, R. and Broecker, W. S. 1993 Pacific carbonate dissolution revisited. Palaeogeography, Palaeoclimatology, Palaeoecology 103: 31–39.CrossRefGoogle Scholar
Paull, C. K., Hills, S. J., Thierstein, H. R., Bonani, G. and Wölfli, W. 1991 14C offsets and apparently non-synchronous δ18O stratigraphies between nannofossil and foraminiferal carbonates. Quaternary Research 35: 274–290.CrossRefGoogle Scholar
Rossignol-Strick, M. and Planchais, N. 1989 Climate patterns revealed by pollen and oxygen isotope records of a Tyrrhenian Sea core. Nature 342: 413–416.CrossRefGoogle Scholar
Ruddiman, W. F., Jones, G. A., Peng, T.-H, Glover, L. K., Glass, B. P. and Liebertz, P. J. 1980 Tests for size and shape dependency in deep-sea mixing. Sedimentary Geology 25: 257–276.CrossRefGoogle Scholar
Sanderson, B. 1985 How bioturbation supports manganese nodules at the sediment-water interface. Deep-Sea Research 32: 1281–1285.CrossRefGoogle Scholar
Schiffelbein, P. 1984 Effect of benthic mixing on the information content of deep-sea stratigraphical signals. Nature 311: 651–653.CrossRefGoogle Scholar
Schiffelbein, P. 1985 Extracting the benthic mixing impulse response function: A constrained deconvolution technique. Marine Geology 64: 313–336.CrossRefGoogle Scholar
Smith, C. R. 1992 Factors controlling bioturbation in deep-sea sediments and their relation to models of carbon diagenesis. In Rowe, G. T. and Pariente, V., eds., Deep-Sea Food Chains and the Global Carbon Cycle. Dordrecht Kluwer Academic Publishers: 375–393.CrossRefGoogle Scholar
Smith, C. R., Pope, R. H., DeMaster, D. J. and Magaard, L. 1993 Age-dependent mixing of deep-sea sediments. Geochimica et Cosmochimica Acta 57: 1473–1488.CrossRefGoogle Scholar
Smith, J. N., Boudreau, B. P., Schafer, C. T. and Noshkin, V. 1986 Plutonium and 210Pb distributions in Northeast Atlantic sediments: Subsurface anomalies caused by non-local mixing. Earth and Planetary Science Letters 81: 15–28.CrossRefGoogle Scholar
Thomson, J., Colley, S., Anderson, R., Cook, G. T. and MacKenzie, A. B. 1993a 210Pb in the sediments and water column of the Northeast Atlantic from 47 to 59°N along 20°W. Earth and Planetary Science Letters 115: 75–87.CrossRefGoogle Scholar
Thomson, J., Colley, S., Anderson, R., Cook, G. T., MacKenzie, A. B. and Harkness, D. D. 1993b Holocene sediment fluxes in the northeast Atlantic from 230Thexcess and radiocarbon measurements. Paleoceanography 8: 631–650.CrossRefGoogle Scholar
Thomson, J., Colley, S. and Weaver, P. P. E. 1988 Bioturbation into a recently emplaced deep-sea turbidite as revealed by 210Pbexcess, 230Thexcess and planktonic foraminifera distributions. Earth and Planetary Science Letters 90: 157–173.CrossRefGoogle Scholar
Thomson, J. and Weaver, P. P. E. 1994 An AMS radiocarbon method to determine the emplacement time of recent deep-sea turbidites. Sedimentary Geology 89: 1–7.CrossRefGoogle Scholar
Wheatcroft, R. A. 1992 Experimental tests for particle size-dependent bioturbation in the deep ocean. Limnology and Oceanography 37: 90–104.CrossRefGoogle Scholar
Wheatcroft, R. A. and Jumars, P. A. 1987 Statistical re-analysis for size dependency in deep-sea mixing. Marine Geology 77: 157–163.CrossRefGoogle Scholar
Wheatcroft, R. A., Jumars, P. A., Smith, C. R. and Nowell, A. R. M. 1990 A mechanistic view of the particulate biodiffusion coefficient: Step lengths, rest periods and transport directions. Journal of Marine Research 48: 177–207.CrossRefGoogle Scholar