Abstract
Marine radiocarbon (14C) dates are widely used for dating oceanic events and as tracers of ocean circulation, essential components for understanding ocean–climate interactions. Past ocean ventilation rates have been determined by the difference between radiocarbon ages of deep-water and surface-water reservoirs, but the apparent age of surface waters (currently ∼400 years in the tropics and ∼1,200 years in Antarctic waters1) might not be constant through time2, as has been assumed in radiocarbon chronologies3,4 and palaeoclimate studies5. Here we present independent estimates of surface-water and deep-water reservoir ages in the New Zealand region since the last glacial period, using volcanic ejecta (tephras) deposited in both marine and terrestrial sediments as stratigraphic markers. Compared to present-day values, surface-reservoir ages from 11,900 14C years ago were twice as large (800 years) and during glacial times were five times as large (2,000 years), contradicting the assumption of constant surface age. Furthermore, the ages of glacial deep-water reservoirs were much older (3,000–5,000 years). The increase in surface-to-deep water age differences in the glacial Southern Ocean suggests that there was decreased ocean ventilation during this period.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Stuiver, M. & Polach, H. A. Discussion and reporting of 14C data. Radiocarbon 19, 355–363 (1977).
Bard, E. et al. The North Atlantic atmosphere-sea surface 14C gradient during the Younger Dryas climatic event. Earth Planet. Sci. Lett. 126, 275–287 (1994).
Edwards, R. L. et al. A large drop in atmospheric 14C/12C and reduced melting in the Younger Dryas, documented with 230Th ages of corals. Science 260, 962–968 (1993).
Hughen, K. A., Overpeck, J. T., Peterson, L. C. & Trumbore, S. Rapid climate changes in the tropical Atlantic during the last deglaciation. Nature 380, 51–54 (1996).
Adkins, J. F. & Boyle, E. A. Changing atmospheric Δ14C and the record of deep water paleoventilation ages. Paleoceanography 12, 337–344 (1997).
Bard, E. Correction of accelerator mass spectrometry 14C ages measured in planktonic foraminifera: Paleoceanographic implications. Paleoceanography 3, 635–646 (1988).
Östlund, G. & Stuiver, M. GEOSECS Pacific radiocarbon. Radiocarbon 22, 25–53 (1980).
Broecker, W. S., Peng, T. -H., Trumbore, S., Bonani, G. & Wolfli, W. The distribution of radiocarbon in the glacial ocean. Glob. Biogeochem. Cycles 4, 103–117 (1990).
Froggatt, P. C. & Lowe, D. J. A review of late Quaternary silicic and some other tephra formations from New Zealand: their stratigraphy, nomenclature, distribution, volume, and age. NZ J. Geol. Geophys. 33, 89–109 (1990).
Carter, L., Nelson, C. S., Neil, H. L. & Froggat, P. C. Correlation, dispersal, and preservation of the Kawakawa Tephra and other late Quaternary tephra layers in the Southwest Pacific Ocean. NZ J. Geol. Geophys. 38, 29–46 (1995).
Kohn, B. P. & Glasby, G. P. Tephra distribution and sedimentation rates in the Bay of Plenty, New Zealand. NZ J. Geol. Geophys. 21, 49–79 (1978).
Higham, T. F. G. & Hogg, A. G. Radiocarbon dating of prehistoric shell from New Zealand and calculation of the ΔR value using fish otoliths. Radiocarbon 37, 409–416 (1996).
Shackleton, N. J. et al. Radiocarbon age of last glacial Pacific deep water. Nature 335, 708–711 (1988).
Stocker, T. F. & Wright, D. G. Rapid changes in ocean circulation and atmospheric radiocarbon. Paleoceanography 11, 773–795 (1996).
Charles, C. D. & Fairbanks, R. G. Evidence from Southern Ocean sediments for the effect of North Atlantic deep-water flux on climate. Nature 355, 416–419 (1992).
Blunier, T. et al. Timing of the Antarctic cold reversal with respect to the Younger Dryas event. Geophys. Res. Lett. 24, 2683–2686 (1997).
Sowers, T. & Bender, M. Climate records covering the last deglaciation. Science 269, 210–213 (1995).
Toggweiler, J. R., Dixon, K. & Broecker, W. S. The Peru upwelling and the ventilation of the South Pacific thermocline. J. Geophys. Res. C 11, 20467–20497 (1991).
Duplessy, J. -C. et al. Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation. Paleoceanography 3, 343–360 (1988).
McCorkle, D. C., Heggie, D. T. & Veeh, H. H. Glacial and Holocene stable isotopic distributions in the southeastern Indian Ocean. Paleoceanography 13, 20–34 (1998).
Howard, W. R. & Prell, W. L. Late Quaternary carbonate production and preservation in the Southern Ocean: Implications for oceanic and atmospheric carbon cycling. Paleoceanography 9, 453–482 (1994).
Francois, R. et al. Contribution of Southern Ocean surface-water stratification to low atmospheric CO2 concentrations during the last glacial period. Nature 389, 929–935 (1997).
Rosenthal, Y., Boyle, E. A. & Labeyrie, L. D. Last glacial maximum paleochemistry and deepwater circulation in the Southern Ocean: Evidence from foraminiferal cadmium. Paleoceanography 12, 787–796 (1997).
Lea, D. W. A trace metal perspective on the evolution of Antarctic Circumpolar Deep Water chemistry. Paleoceanography 10, 733–748 (1995).
Yu, E. -F., Francois, R. & Bacon, M. P. Similar rates of modern and last-glacial thermohaline circulation inferred from radiochemical data. Nature 379, 689–694 (1996).
Finkel, R. C. & Nishiizumi, K. Beryllium 10 concentrations in the Greenland Ice Sheet Project 2 ice core from 3-40 ka. J. Geophys. Res. 102, 26699–26706 (1997).
Guyodo, Y. & Valet, J.-P. Relative variations in geomagnetic intensity from sedimentary records: the past 200,000 years. Earth Planet. Sci. Lett. 143, 23 (1996).
Kitigawa, H. & van der Plicht, J. A 40,000-year varve chronology from Lake Suigetsu, Japan: Extension of the 14C calibration curve. Radiocarbon 40, 505–515 (1998).
Fairbanks, R. G., Wiebe, P. H. & Bé, A. W. H. Vertical distribution and isotopic composition of living planktonic foraminifera in the western North Atlantic. Science 207, 61–63 (1979).
Wright, I. C., McGlone, M. S., Nelson, C. S. & Pillans, B. J. An integrated latest Quaternary (Stage 3 to present) paleoclimatic and paleoceanographic record from offshore northern New Zealand. Quat. Res. 44, 283–293 (1995).
Weaver, P. P. E., Neil, H. L. & Carter, L. Sea surface temperature estimates from the Southwest Pacific based on planktonic foraminifera and oxygen isotopes. Palaeogeogr. Palaeoclimatol. Palaeoecol. 131, 241–256 (1997).
Acknowledgements
We thank E. Bard and J. Southon for discussions and comments. L. Carter kindly provided material from the core collection and modern shells were provided by W. Blom. L. Robertson helped produce the figures and P. Shane helped with tephra identifications. Radiocarbon analyses at CAMS were performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sikes, E., Samson, C., Guilderson, T. et al. Old radiocarbon ages in the southwest Pacific Ocean during the last glacial period and deglaciation. Nature 405, 555–559 (2000). https://doi.org/10.1038/35014581
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/35014581
This article is cited by
-
Atlantic inflow and low sea-ice cover in the Nordic Seas promoted Fennoscandian Ice Sheet growth during the Last Glacial Maximum
Communications Earth & Environment (2023)
-
Southern Ocean glacial conditions and their influence on deglacial events
Nature Reviews Earth & Environment (2023)
-
Variable ventilation ages in the equatorial Indian Ocean thermocline during the LGM
Scientific Reports (2023)
-
Southern Ocean contribution to both steps in deglacial atmospheric CO2 rise
Scientific Reports (2021)
-
Radiocarbon dating
Nature Reviews Methods Primers (2021)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.