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Datasets of project "South Atlantic in Late Quaternary: Reconstruction of Budget and Currents"

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  1. Cadmium analytical results from sediment and foraminifera shells

    Boyle, Edwards A; Rosenthal, Yair
    There has been a major contradiction between benthic foraminiferal Cd/Ca and d13C data concerning the labile nutrient chemistry of the Southern Ocean during the Last Glacial Maximum (LGM). Cd data indicates that LGM South Atlantic nutrient concentrations were as low as they are today, indicative of a persistent influx of nutrient-depleted North Atlantic Deep Water (NADW). d13C data indicates that LGM South Atlantic nutrient concentrations were much higher than at present (even higher than anywhere else in the ocean at that time), and these data have been interpreted as signifying the complete shutdown ofthe export of NADW into the global...

  2. Cadmium analytical results from sediment and foraminifera shells

    Boyle, Edwards A; Rosenthal, Yair
    There has been a major contradiction between benthic foraminiferal Cd/Ca and d13C data concerning the labile nutrient chemistry of the Southern Ocean during the Last Glacial Maximum (LGM). Cd data indicates that LGM South Atlantic nutrient concentrations were as low as they are today, indicative of a persistent influx of nutrient-depleted North Atlantic Deep Water (NADW). d13C data indicates that LGM South Atlantic nutrient concentrations were much higher than at present (even higher than anywhere else in the ocean at that time), and these data have been interpreted as signifying the complete shutdown ofthe export of NADW into the global...

  3. Table 2. Bulk sedimentary Cd content for sediment core RC13-228

    Boyle, Edwards A; Rosenthal, Yair

  4. Table 2. Bulk sedimentary Cd content for sediment core RC13-228

    Boyle, Edwards A; Rosenthal, Yair

  5. Table 1. Comparison of samples cleaned by old and new methods for various cores

    Boyle, Edwards A; Rosenthal, Yair

  6. Table 1. Comparison of samples cleaned by old and new methods for various cores

    Boyle, Edwards A; Rosenthal, Yair

  7. Table 2. 14C AMS datings for sediment core T89-24

    Jansen, J H Fred; Ufkes, Els; Schneider, Ralph R
    Planktic foraminifera data from three cores of the Angola-Zaire margin are used to reconstruct palaeopositions of the Angola-Benguela Front (ABF) between the warm Angola Current and cold Benguela Current for the last 180,000 years. Strong northward shifts occurred in stages 4 and 3.3-3.1, but not in stages 6 and 2. The Benguela Current did not penetrate into the Gulf of Guinea. The southernmost positions, not far from the present one, were occupied in stages 5.5 and 1, but also in stage 6.3. The record of the shifts contains significant variance in the 23 ky**-1 orbital frequency band and there are...

  8. Table 2. 14C AMS datings for sediment core T89-24

    Jansen, J H Fred; Ufkes, Els; Schneider, Ralph R
    Planktic foraminifera data from three cores of the Angola-Zaire margin are used to reconstruct palaeopositions of the Angola-Benguela Front (ABF) between the warm Angola Current and cold Benguela Current for the last 180,000 years. Strong northward shifts occurred in stages 4 and 3.3-3.1, but not in stages 6 and 2. The Benguela Current did not penetrate into the Gulf of Guinea. The southernmost positions, not far from the present one, were occupied in stages 5.5 and 1, but also in stage 6.3. The record of the shifts contains significant variance in the 23 ky**-1 orbital frequency band and there are...

  9. Oxygen and silica flux from 9 multicorer profiles

    Holstein, Jan M; Hensen, Christian
    Pore water profiles from 24 stations in the South Atlantic (located in the Guinea, Angola, Cape, Guyana, and Argentine basins) show good correlations of oxygen and silicon, suggesting microbially mediated dissolution of biogenic silica. We used simple analytical transport and reaction models to show the tight coupling of the reconstructed process kinetics of aerobic respiration and silicon regeneration. A generic transport and reaction model successfully reproduced the majority of Si pore water profiles from aerobic respiration rates, confirming that the dissolution of biogenic silica (BSi) occurs proportionally to O2 consumption. Possibly limited to well-oxygenated sediments poor in BSi, benthic Si...

  10. Oxygen and silica flux from 9 multicorer profiles

    Holstein, Jan M; Hensen, Christian
    Pore water profiles from 24 stations in the South Atlantic (located in the Guinea, Angola, Cape, Guyana, and Argentine basins) show good correlations of oxygen and silicon, suggesting microbially mediated dissolution of biogenic silica. We used simple analytical transport and reaction models to show the tight coupling of the reconstructed process kinetics of aerobic respiration and silicon regeneration. A generic transport and reaction model successfully reproduced the majority of Si pore water profiles from aerobic respiration rates, confirming that the dissolution of biogenic silica (BSi) occurs proportionally to O2 consumption. Possibly limited to well-oxygenated sediments poor in BSi, benthic Si...

  11. Calculated oxygen and silicon benthic fluxes in sediments of the South Atlantic

    Holstein, Jan M; Hensen, Christian

  12. Calculated oxygen and silicon benthic fluxes in sediments of the South Atlantic

    Holstein, Jan M; Hensen, Christian

  13. Biogenic silica depth profiles in sediments of the South Atlantic

    Holstein, Jan M; Hensen, Christian

  14. Biogenic silica depth profiles in sediments of the South Atlantic

    Holstein, Jan M; Hensen, Christian

  15. Stable isotopes of foraminifers, mineralogy and ages of sediment core GeoB1523-1

    Rühlemann, Carsten; Diekmann, Bernhard; Mulitza, Stefan; Frank, Martin
    Today the western tropical Atlantic is the most important passage for cross-equatorial transfer of heat in the form of warm surface water flowing from the South into the North Atlantic. Circulation changes north of South America may thus have influenced the global thermohaline circulation system and high northern latitude climate. Here we reconstruct late Quaternary variations of western equatorial Atlantic surface circulation and Amazon lowland climate obtained from a multiproxy sediment record from Ceará Rise. Variations in the illite/smectite ratio suggest drier climatic conditions in the Amazon Basin during glacials relative to interglacials. The 230Thex-normalized fluxes and the 13C/12C record...

  16. Stable isotopes of foraminifers, mineralogy and ages of sediment core GeoB1523-1

    Rühlemann, Carsten; Diekmann, Bernhard; Mulitza, Stefan; Frank, Martin
    Today the western tropical Atlantic is the most important passage for cross-equatorial transfer of heat in the form of warm surface water flowing from the South into the North Atlantic. Circulation changes north of South America may thus have influenced the global thermohaline circulation system and high northern latitude climate. Here we reconstruct late Quaternary variations of western equatorial Atlantic surface circulation and Amazon lowland climate obtained from a multiproxy sediment record from Ceará Rise. Variations in the illite/smectite ratio suggest drier climatic conditions in the Amazon Basin during glacials relative to interglacials. The 230Thex-normalized fluxes and the 13C/12C record...

  17. Benthic foraminifera in South Atlantic Ocean surface sediments

    Schumacher, Stefanie
    Benthic foraminiferal assemblages were analyzed on forty-eight surfacesediment samples which were taken with a multiple corer from the southern South Atlantic Ocean and the northern Angola-Basin. The short cores were split into 1-cm-thick slices down to 15 cm sediment depth. Live (with Rose Bengal stained) and dead faunas were counted separately. The data were used to calculate numerical faunal characteristics like standing stocks, benthic foraminifera accumulation rates, diversity, average living depth, and habitat depth. Additionally the live and dead faunas were grouped into a number of principal faunal endmembers by Q-mode principal component analysis. Faunal composition, numerical faunal characteristics, and...

  18. Benthic foraminifera in South Atlantic Ocean surface sediments

    Schumacher, Stefanie
    Benthic foraminiferal assemblages were analyzed on forty-eight surfacesediment samples which were taken with a multiple corer from the southern South Atlantic Ocean and the northern Angola-Basin. The short cores were split into 1-cm-thick slices down to 15 cm sediment depth. Live (with Rose Bengal stained) and dead faunas were counted separately. The data were used to calculate numerical faunal characteristics like standing stocks, benthic foraminifera accumulation rates, diversity, average living depth, and habitat depth. Additionally the live and dead faunas were grouped into a number of principal faunal endmembers by Q-mode principal component analysis. Faunal composition, numerical faunal characteristics, and...

  19. (Fig. 16) Grain-sizes of magnetosomes from sediment core GeoB1713-5

    Frederichs, Thomas; Schmidt, Andrea

  20. (Fig. 16) Grain-sizes of magnetosomes from sediment core GeoB1713-5

    Frederichs, Thomas; Schmidt, Andrea

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