between 170 cm and 140 cm, while those of N. pachyderma
decreased. Moreover, the latter are much older than the
subpolar species. The abundance of these species varies
along core depth and peaks of abundance spreads over
several tens of cm. The
14 C age distribution of the two
species is due to bioturbation, a mixing process of sediment
grains by benthic organisms, which move up and down
through the sedimentary deposits. Applying a simple mixing
filter of a constant thickness (h) over time, we can observe
that the estimated abundance is lower than at the time of
deposition. The abundance peak is no longer at its initial
position in the sediment, and its position depends of the
mixing depth (h) (Fig. 4.12). In the examples, the bioturbation effects on
14 C ages led to lower the
14 C age with
respect to the ‘real’
14 C age at the onset of the event. The
effect is 900 and 1400 years depending on the h value with a
sedimentation rate of 10 cm per 1000 years. A much higher
sedimentation rate of 30 cm per 1000 years tends to lower
the bioturbation effects as the
14 C ages decrease by
270 years and 420 years, with h equal to 10 cm and 15 cm
respectively. The
14
C age of the end of the event increased
by 600 years using a sedimentation rate of 10 cm per
1000 years. The higher the sedimentation rates, the lower the
impact of bioturbation on the
14 C ages.
Accurate marine
14 C ages are obtained from the
14 C
dating of foraminifera picked at the depth of maximum
abundance in deep-sea cores with a high sedimentation rate.
The example on Fig. 4.11 also emphasizes that the selected
species must be in adequacy with the climatic period to be
dated. The variability in the compiled deep and surface Δ
14 C
values in Zhao et al. (2018) may be partly explained by
bioturbation and inadequately dated species.
References
Adkins, J. F., Cheng, H., Boyle, E. A., Druffel, E. R., & Edwards, R. L.
(1998). Deep-sea coral evidence for rapid change in ventilation of
the deep North Atlantic 15,400 years ago. Science, 280, 725–728.
Arnold, J. R., & Libby, W. F. (1949). Age determinations by
radiocarbon content: Checks with samples of known Age. Science,
110, 678–680.
Ascough, P. L., Cook, G. T., & Dugmore, A. J. (2009). North Atlantic
marine
14
C reservoir effects: Implications for late-Holocene chronological studies Quaternary. Geochronology, 4, 171–180.
Austin, W. E. N., Telford, R. J., Ninnemann, U. S., Brown, L., Wilson,
L. J., Small, D. P., & Bryant, C. L. (2011). North Atlantic reservoir
ages linked to high Younger Dryas atmospheric radiocarbon
concentrations. Global and Planetary Change, 79, 226–233.
Balesdent, J., & Guillet, B. (1982). Les datations par le
14
C des
matières organiques des sols. Science du sol, 2, 93–112.
Bard, E. (1988). Correction of accelerator mass spectrometry
14
C ages
measured in planktonic foraminifera: Paleoceanographic implications. Paleoceanography, 3, 635–645.
Bard, E., Arnold, M., Duprat, J., Moyes, J., & Duplessy, J. C. (1987).
Reconstruction of the last deglaciation: Deconvolved records of
d
18
O profiles, micropaleontological variations and accelerator mass
spectrometric
14
C dating. Climate Dynamics, 1, 101–112.
Bard, E., Arnold, M., Mangerud, J., Paterne, M., Labeyrie, L., Duprat,
J., et al. (1994). The North Atlantic atmosphere-sea surface
14
C
gradient during the Younger Dryas climatic event. Earth and
Planetary Science Letters, 126, 275–287.
Bard, E., Hamelin, B., Fairbanks, R. G., & Zindler, A. (1990).
Calibration of the
14
C timescale over the past 30,000 years using
mass spectrometric U-Th ages from Barbados corals. Nature, 345,
405–410.
Beck, J. W., Richards, D. A., Edwards, R. L., Bernard, W., Silverman,
B. W., Smart, P. L., et al. (2001). Extremely large variations of
atmospheric C-14 concentration during the last glacial period.
Science, 292, 2453–2458.
Blunier, T., Chappellaz, J., Schwander, J., Dällenbach, A., Stauffer, B.,
Stocker, T., et al. (1998). Asynchrony of Antarctic and Greenland
climate change during the last glacial period. Nature, 394, 739–743.
Bondevik, S., Mangerud, J., Birks, H. H., Gulliksen, S., & Reimer,
P. (2006). Changes in North Atlantic radiocarbon reservoir ages
during the Allerød and Younger Dryas. Science, 312, 1514–1517.
Broecker, W. B. F. (1998). Paleocean Circulation During the Last
Deglaciation: A Bipolar Seesaw. Paleoceanography, 13, 119–121.
Broecker, W. S., & Olson, E. A. (1959). Lamont radiocarbon
measurements VI. American Journal of Science. Radiocarbon
Supplement, 1, 111–132.
Broecker, W. S., Sutherland, S., Smethie, W., Peng, T. S., & Ostlund,
G. (1995). Oceanic radiocarbon: Separation of the natural and bomb
component. Global Biogeochemical Cycles, 9, 263–288.
Burke, A., & Robinson, L. F. (2012). The Southern Ocean’s role in
carbon exchange during the last deglaciation. Science, 335, 557–
561.
Chen, T., Robinson, L. F., Burke, A., Southon, J., Spooner, P., Morris,
P. J., et al. (2015). Synchronous centennial abrupt events in the
ocean and atmosphere during the last deglaciation. Science, 349
(6255), 1537–1541.
Chiu, T. C., Fairbanks, R. G., Cao, L., & Mortlock, R. A. (2007).
Analysis of the atmospheric C-14 record spanning the past 50 000
years derived from high-precision Th-230/U-234/U-238,
Pa-231/U-235 and C-14 dates on fossil corals. Quaternary Science
Review, 26, 18–36.
Currie, L. A. (2004). The remarkable metrological history of radiocarbon dating. Journal of Research of the National Institute of
Standards and Technology, 109, 185–217.
Cuzange, M. T., Delque-Kolic, E., Goslar, T., Grootes, P. M., Higham,
T., Kaltnecker, E., et al. (2007). Radiocarbon intercomparison
program for the chauvet cave. Radiocarbon, 49, 339–347.
Damon, P. E., Lerman, J. C., & Long, A. (1978). Temporal fluctuations
of atmospheric
14 C: Causal factors and implications. The Annual
Review of Earth and Planetary Sciences, 6, 457–494.
Damon, P. E., & Peristykh, A. N. (2000). Radiocarbon calibration and
application to geophysics, solar physics, and astrophysics. Radiocarbon, 42, 137–150.
Druffel, E. R. M. (1989). Decade time scale variability of ventilation in
the North Atlantic: High-precision measurements of bomb radiocarbon in banded corals. Journal of Geophysical Research, 94,
3271–3285.
Engelkemeir, A., Hamill, W. H., Inghram, M. G., & Libby, W. F.
(1949). The half-life of radiocarbon (
14
C). The Physical Review, 75,
1825–1833.
Ezat, M. M., Rasmussen, T. L., Thornalley, D. J. R., Olsen, J., Skinner,
L. C., Hönisch, B., et al. (2017). Ventilation history of Nordic Seas
over-flows during the last (de)glacial period revealed by
species-specific benthic foraminiferal
14
C dates. Paleoceanography,
32, 172–181.
4 Carbon-14
69
decreased. Moreover, the latter are much older than the
subpolar species. The abundance of these species varies
along core depth and peaks of abundance spreads over
several tens of cm. The
14 C age distribution of the two
species is due to bioturbation, a mixing process of sediment
grains by benthic organisms, which move up and down
through the sedimentary deposits. Applying a simple mixing
filter of a constant thickness (h) over time, we can observe
that the estimated abundance is lower than at the time of
deposition. The abundance peak is no longer at its initial
position in the sediment, and its position depends of the
mixing depth (h) (Fig. 4.12). In the examples, the bioturbation effects on
14 C ages led to lower the
14 C age with
respect to the ‘real’
14 C age at the onset of the event. The
effect is 900 and 1400 years depending on the h value with a
sedimentation rate of 10 cm per 1000 years. A much higher
sedimentation rate of 30 cm per 1000 years tends to lower
the bioturbation effects as the
14 C ages decrease by
270 years and 420 years, with h equal to 10 cm and 15 cm
respectively. The
14
C age of the end of the event increased
by 600 years using a sedimentation rate of 10 cm per
1000 years. The higher the sedimentation rates, the lower the
impact of bioturbation on the
14 C ages.
Accurate marine
14 C ages are obtained from the
14 C
dating of foraminifera picked at the depth of maximum
abundance in deep-sea cores with a high sedimentation rate.
The example on Fig. 4.11 also emphasizes that the selected
species must be in adequacy with the climatic period to be
dated. The variability in the compiled deep and surface Δ
14 C
values in Zhao et al. (2018) may be partly explained by
bioturbation and inadequately dated species.
References
Adkins, J. F., Cheng, H., Boyle, E. A., Druffel, E. R., & Edwards, R. L.
(1998). Deep-sea coral evidence for rapid change in ventilation of
the deep North Atlantic 15,400 years ago. Science, 280, 725–728.
Arnold, J. R., & Libby, W. F. (1949). Age determinations by
radiocarbon content: Checks with samples of known Age. Science,
110, 678–680.
Ascough, P. L., Cook, G. T., & Dugmore, A. J. (2009). North Atlantic
marine
14
C reservoir effects: Implications for late-Holocene chronological studies Quaternary. Geochronology, 4, 171–180.
Austin, W. E. N., Telford, R. J., Ninnemann, U. S., Brown, L., Wilson,
L. J., Small, D. P., & Bryant, C. L. (2011). North Atlantic reservoir
ages linked to high Younger Dryas atmospheric radiocarbon
concentrations. Global and Planetary Change, 79, 226–233.
Balesdent, J., & Guillet, B. (1982). Les datations par le
14
C des
matières organiques des sols. Science du sol, 2, 93–112.
Bard, E. (1988). Correction of accelerator mass spectrometry
14
C ages
measured in planktonic foraminifera: Paleoceanographic implications. Paleoceanography, 3, 635–645.
Bard, E., Arnold, M., Duprat, J., Moyes, J., & Duplessy, J. C. (1987).
Reconstruction of the last deglaciation: Deconvolved records of
d
18
O profiles, micropaleontological variations and accelerator mass
spectrometric
14
C dating. Climate Dynamics, 1, 101–112.
Bard, E., Arnold, M., Mangerud, J., Paterne, M., Labeyrie, L., Duprat,
J., et al. (1994). The North Atlantic atmosphere-sea surface
14
C
gradient during the Younger Dryas climatic event. Earth and
Planetary Science Letters, 126, 275–287.
Bard, E., Hamelin, B., Fairbanks, R. G., & Zindler, A. (1990).
Calibration of the
14
C timescale over the past 30,000 years using
mass spectrometric U-Th ages from Barbados corals. Nature, 345,
405–410.
Beck, J. W., Richards, D. A., Edwards, R. L., Bernard, W., Silverman,
B. W., Smart, P. L., et al. (2001). Extremely large variations of
atmospheric C-14 concentration during the last glacial period.
Science, 292, 2453–2458.
Blunier, T., Chappellaz, J., Schwander, J., Dällenbach, A., Stauffer, B.,
Stocker, T., et al. (1998). Asynchrony of Antarctic and Greenland
climate change during the last glacial period. Nature, 394, 739–743.
Bondevik, S., Mangerud, J., Birks, H. H., Gulliksen, S., & Reimer,
P. (2006). Changes in North Atlantic radiocarbon reservoir ages
during the Allerød and Younger Dryas. Science, 312, 1514–1517.
Broecker, W. B. F. (1998). Paleocean Circulation During the Last
Deglaciation: A Bipolar Seesaw. Paleoceanography, 13, 119–121.
Broecker, W. S., & Olson, E. A. (1959). Lamont radiocarbon
measurements VI. American Journal of Science. Radiocarbon
Supplement, 1, 111–132.
Broecker, W. S., Sutherland, S., Smethie, W., Peng, T. S., & Ostlund,
G. (1995). Oceanic radiocarbon: Separation of the natural and bomb
component. Global Biogeochemical Cycles, 9, 263–288.
Burke, A., & Robinson, L. F. (2012). The Southern Ocean’s role in
carbon exchange during the last deglaciation. Science, 335, 557–
561.
Chen, T., Robinson, L. F., Burke, A., Southon, J., Spooner, P., Morris,
P. J., et al. (2015). Synchronous centennial abrupt events in the
ocean and atmosphere during the last deglaciation. Science, 349
(6255), 1537–1541.
Chiu, T. C., Fairbanks, R. G., Cao, L., & Mortlock, R. A. (2007).
Analysis of the atmospheric C-14 record spanning the past 50 000
years derived from high-precision Th-230/U-234/U-238,
Pa-231/U-235 and C-14 dates on fossil corals. Quaternary Science
Review, 26, 18–36.
Currie, L. A. (2004). The remarkable metrological history of radiocarbon dating. Journal of Research of the National Institute of
Standards and Technology, 109, 185–217.
Cuzange, M. T., Delque-Kolic, E., Goslar, T., Grootes, P. M., Higham,
T., Kaltnecker, E., et al. (2007). Radiocarbon intercomparison
program for the chauvet cave. Radiocarbon, 49, 339–347.
Damon, P. E., Lerman, J. C., & Long, A. (1978). Temporal fluctuations
of atmospheric
14 C: Causal factors and implications. The Annual
Review of Earth and Planetary Sciences, 6, 457–494.
Damon, P. E., & Peristykh, A. N. (2000). Radiocarbon calibration and
application to geophysics, solar physics, and astrophysics. Radiocarbon, 42, 137–150.
Druffel, E. R. M. (1989). Decade time scale variability of ventilation in
the North Atlantic: High-precision measurements of bomb radiocarbon in banded corals. Journal of Geophysical Research, 94,
3271–3285.
Engelkemeir, A., Hamill, W. H., Inghram, M. G., & Libby, W. F.
(1949). The half-life of radiocarbon (
14
C). The Physical Review, 75,
1825–1833.
Ezat, M. M., Rasmussen, T. L., Thornalley, D. J. R., Olsen, J., Skinner,
L. C., Hönisch, B., et al. (2017). Ventilation history of Nordic Seas
over-flows during the last (de)glacial period revealed by
species-specific benthic foraminiferal
14
C dates. Paleoceanography,
32, 172–181.
4 Carbon-14
69