Figure 2. Carbon dioxide concentrations in the Vostok ice core from Antarctica (Barnola et al., 1987; Jouzel et al., 1993; solid triangles), compared with a productivity-related carbon isotope signal from the eastern tropical Pacific (difference between the delta13C values of planktonic and benthic foraminifera; Shackleton et al., 1983; heavy line), show that ocean productivity and atmospheric CO2 tend to vary together. Time scale of Barnola et al. is adjusted to the one of Shackleton et al. by correlation of the deuterium signal in the ice with the oxygen isotope signal in the sediment (from Berger et al., 1996).
Figure 3. Comparison of ice-core CO2 record of Barnola et al. (1987) with surface water pCO2 estimates for Core GeoB 1016-3, using conversion for delta13C of organic matter to CO2 pressure as proposed by Popp et al. (1989) and Rau et al. (1991). Time scale of Vostok ice core adjusted for best fit. (From Müller et al., 1994).
Figure 4. Relationship between delta18O record and delta13C
record of benthic foraminifers, DSDP Site 216, tropical Indian Ocean. It suggests that extraction of
organic carbon in upwelling regions during Monterey time eventually resulted in cooling because
of downdraw of atmospheric pCO2 (after Vincent and Berger, 1985).
Figure 5. The cooling step observed between 2.5 and 3 Ma (as seen in the shift to more positive
values of delta18O) marks a change toward greater instability of climate, as seen
in increased fluctuations of delta18O values of planktonic foraminifers
(Neogloboquadrina pachyderma, Globigerina bulloides) and benthic foraminifers (Cibicides spp.)
sampled near the boundary between the South Atlantic and Southern oceans. From Hodell and
Venz (1992).
Figure 6. Angola/Namibia upwelling system off southern Africa, as seen in productivity
distributions. Modified from Berger (1989). Numbers are the primary production in
g°C/m2yr; black areas have primary production values greater than 180
g°C/m2yr.
Figure 7. Conceptual model showing areas where low-oxygen water is formed in the Southeast
Atlantic and the inferred movement of this water (dashed arrows; from Chapman and Shannon,
1987).
Figure 8. Schematic representation of the large-scale, upper-level geostrophic currents and fronts in the South Atlantic Ocean. After Peterson and Stramma (1991) with minor additions from several other compilations.
Figure 9. Depositional cycles in biogenous sediments on Walvis Ridge, in the Benguela System.
Note overall trend in diatom abundance, with maximum in early Quaternary (after Dean and
Gardner [1985] and Hay and Brock [1992]).
Figure 10. Meridional heat transport in the Indian and Atlantic Oceans (from Woods, 1981,
modified). Note the major transfer of heat from the Indian Ocean to the Atlantic, which can be
modulated through time by changing the position of the subantarctic frontal system.
Figure 11. Estimates for annual heat transports for the present world ocean (heavy solid line with thin lines showing the approximate error bounds) and for the Atlantic (present conditions and last glacial maximum, as labeled). From Berger and Wefer (1996a), after Miller and Russell (1989), modified. Note the anomalous pattern for the present South Atlantic and the more symmetric pattern for glacial conditions.
Figure 12. Deep-water patterns and flow in the South Atlantic during the present (a, b) and the last glacial maximum (c). (a) Present salinity distributions; from Sverdrup et al. (1942), according to G. Wüst. (b) Distribution of delta13C values in dissolved inorganic carbon; from Kroopnick (1980). (c) Distribution of delta13C values in dissolved inorganic carbon, 20 k.y. ago, inferred from delta13C values in benthic foraminifers of that age; source: Berger and Wefer (1996a), after Duplessy et al. (1988) and Sarnthein et al. (1994).
Figure 13. Plot of carbon isotope records, measured on the benthic foraminifer taxon C. wuellerstorfi, as a function of time. From Bickert and Wefer (1996). Numbers are core labels, in the GeoB collections.
Figure 14. Zonal section of nitrate concentrations at 11°20'S. From Siedler et al. (1996).
Figure 15. Seismic lines and proposed drill sites in the Lower Congo Basin (LCB).
Figure 16. Seismic lines and proposed drill sites in the Mid-Angola Basin (MAB).
Figure 17. Seismic lines and proposed drill Site SAB-2 in the Southern Angola Basin (SAB).
Figure 18. Seismic lines and proposed drill sites in the Walvis Basin (WB).
Figure 19. Seismic lines and proposed drill Site NCB-2B in the Northern Cape Basin (NCB).
Figure 20. Seismic lines and proposed drill Site MCB-A in the Mid-Cape Basin (MCB).
Figure 21. Seismic lines and proposed drill Site SCB-1 in the Southern Cape Basin (SCB).
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