108
D. Seidov . B. J. Haupt
imentation patterns differ fundamentally from the Holocene/Modern pattern
in a way that cannot be expected a priori. The major differences indicated by
sediment transport and trajectory-tracing models are summarized in following conclusions.
4. The results of sediment transport model suggest that there was almost no sediment deposition in the Gulf Stream area, and a lower rate than at present in
the Caribbean during MWE.
5. The trajectory-tracing model indicates far stronger ventilation of the thermocline in the glacial low latitudes than is observed today. The trajectory-tracing
model indicates complete absence of the deep ocean ventilation at the MWE.
The model reveals disappearance of the deep western boundary current and
westward contraction of the subtropical warm pool. This contraction leads to
collapse of the eastern continuation of the North Atlantic drift and contributes to formation of the upper ocean reverse conveyor.
6. Concerning the use of numerical models as a principal source of sediment
transport and Lagrangian calculations, it should be stressed that at high latitudes, the sediment transport and water-volume tracing models can only operate with the simulated rather than observed circulation patterns. The water
transport calculations depend critically on knowledge about where the convection occurs and how deep it ventilates.
Acknowledgements
This study could not have been carried out without the efforts invested by the
Kiel group into paleoreconstructions of the glacial-interglacial North Atlantic.
We are especially grateful to Michael Sarnthein for inspiring us to study the
meltwater oceanography using the reconstructions provided by the Kiel group
and Karl Stattegger for the support and helpful comments. We deeply appreciate
Avan Antia's help on correcting our English. The study was accomplished within
the framework of the German Climate Program and supported by the Deutsche
Forschungsgemeinschaft (DFG) and SFB313 of Kiel University.
References
Bard, E., F. Rostek, and C. Sonzogni, Interhemispheric synchrony of the last deglaciation inferred from alkenone palaeothermometry, Nature, 385, 707-7101997.
Beck, J. w., J. Recy, F. Taylor, R. L. Edwards, and G. Cabioch, Abrrupt changes in early
Holocene tropical sea-surface temperature derived from coral records, Nature, 385, 7057071997.
Beveridge, N. A. S., H. Elderfield, and N. J. Shackleton, Deep thermohaline circulation in the
low-latitude Atlantic during the last glacial, Paleoceanography, 10,643-660 1995.
Bitzer, K., and R. Pflug, DEPOD: A three-dimensional model for simulating clastic sedimentation and isostatic compensation in sedimentary basin, in Quantitative Dynamics
Stratigraphy, edited by T. A. Cross, pp. 335-348, Prentice Hall, New York 1990.
Bohrmann, G., R. Henrich, and J. Thiede, Miocene to Quaternary paleoceanography in the
northern North Atlantic: Variability in carbonate and biogenic opal accumulation, in Ge-
D. Seidov . B. J. Haupt
imentation patterns differ fundamentally from the Holocene/Modern pattern
in a way that cannot be expected a priori. The major differences indicated by
sediment transport and trajectory-tracing models are summarized in following conclusions.
4. The results of sediment transport model suggest that there was almost no sediment deposition in the Gulf Stream area, and a lower rate than at present in
the Caribbean during MWE.
5. The trajectory-tracing model indicates far stronger ventilation of the thermocline in the glacial low latitudes than is observed today. The trajectory-tracing
model indicates complete absence of the deep ocean ventilation at the MWE.
The model reveals disappearance of the deep western boundary current and
westward contraction of the subtropical warm pool. This contraction leads to
collapse of the eastern continuation of the North Atlantic drift and contributes to formation of the upper ocean reverse conveyor.
6. Concerning the use of numerical models as a principal source of sediment
transport and Lagrangian calculations, it should be stressed that at high latitudes, the sediment transport and water-volume tracing models can only operate with the simulated rather than observed circulation patterns. The water
transport calculations depend critically on knowledge about where the convection occurs and how deep it ventilates.
Acknowledgements
This study could not have been carried out without the efforts invested by the
Kiel group into paleoreconstructions of the glacial-interglacial North Atlantic.
We are especially grateful to Michael Sarnthein for inspiring us to study the
meltwater oceanography using the reconstructions provided by the Kiel group
and Karl Stattegger for the support and helpful comments. We deeply appreciate
Avan Antia's help on correcting our English. The study was accomplished within
the framework of the German Climate Program and supported by the Deutsche
Forschungsgemeinschaft (DFG) and SFB313 of Kiel University.
References
Bard, E., F. Rostek, and C. Sonzogni, Interhemispheric synchrony of the last deglaciation inferred from alkenone palaeothermometry, Nature, 385, 707-7101997.
Beck, J. w., J. Recy, F. Taylor, R. L. Edwards, and G. Cabioch, Abrrupt changes in early
Holocene tropical sea-surface temperature derived from coral records, Nature, 385, 7057071997.
Beveridge, N. A. S., H. Elderfield, and N. J. Shackleton, Deep thermohaline circulation in the
low-latitude Atlantic during the last glacial, Paleoceanography, 10,643-660 1995.
Bitzer, K., and R. Pflug, DEPOD: A three-dimensional model for simulating clastic sedimentation and isostatic compensation in sedimentary basin, in Quantitative Dynamics
Stratigraphy, edited by T. A. Cross, pp. 335-348, Prentice Hall, New York 1990.
Bohrmann, G., R. Henrich, and J. Thiede, Miocene to Quaternary paleoceanography in the
northern North Atlantic: Variability in carbonate and biogenic opal accumulation, in Ge-