Supplementary material to "New insights of the influence of ocean circulation on the sedimentary distribution in the Southwestern Atlantic margin (23° S to 55° S) based on Nd and Pb isotopic fingerprinting"

2021 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Roberto Violante ◽  
Paula Franco-Fraguas ◽  
Leticia Burone ◽  
Cesar Barbedo Rocha ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Southwestern Atlantic ◽  
Supplementary Material ◽  
Atlantic Margin ◽  
Isotopic Fingerprinting

scholarly journals Control of oceanic circulation on sediment distribution in the southwestern Atlantic margin (23 to 55° S)

Ocean Science ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. 1213-1229
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Roberto Violante ◽  
Paula Franco-Fraguas ◽  
Leticia Burone ◽  
Cesar Barbedo Rocha ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Intermediate Water ◽  
Oceanic Circulation ◽  
Southwestern Atlantic ◽  
Sediment Distribution ◽  
Isotopic Signatures ◽  
The North ◽  
Brazil Current ◽  
Lower Circumpolar Deep Water ◽  
Atlantic Margin

Abstract. In this study, we interpret the role played by ocean circulation in sediment distribution on the southwestern Atlantic margin using radiogenic Nd and Pb isotopes. The latitudinal trends for Pb and Nd isotopes reflect the different current systems acting on the margin. The utilization of the sediment fingerprinting method allowed us to associate the isotopic signatures with the main oceanographic features in the area. We recognized differences between Nd and Pb sources to the Argentinean shelf (carried by the flow of Subantarctic Shelf Water) and slopes (transported by deeper flows). Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate areas (the upper 1200 m), the transfer of sediments from the Argentinean margin to the north of 35∘ S is limited by the Subtropical Shelf Front and the basin-wide recirculated Antarctic Intermediate Water. On the southern Brazilian inner and middle shelf, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. Another flow responsible for sediment transport and deposition on the outer shelf and slope is the southward flow of the Brazil Current. Finally, we propose that the Brazil–Malvinas Confluence and the Santos Bifurcation act as boundaries of geochemical provinces in the area. A conceptual model of sediment sources and transport is provided for the southwestern Atlantic margin.

scholarly journals New insights of the influence of ocean circulation on the sedimentary distribution in the Southwestern Atlantic margin (23° S to 55° S) based on Nd and Pb isotopic fingerprinting

2021 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Roberto Violante ◽  
Paula Franco-Fraguas ◽  
Leticia Burone ◽  
Cesar Barbedo Rocha ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Intermediate Water ◽  
Southwestern Atlantic ◽  
Sediment Distribution ◽  
Isotopic Signatures ◽  
The North ◽  
Brazil Current ◽  
Lower Circumpolar Deep Water ◽  
Atlantic Margin ◽  
Current Systems

Abstract. In this work, we provide an extensive inventory of Pb and Nd radiogenic isotopes in surface sediments from the Southwestern Atlantic margin, aiming to interpret the role played by ocean circulation in sediment distribution. There are latitudinal trends for Pb and Nd isotopes, reflecting the different current systems acting on the margin. The utilization of sediment fingerprinting allowed us to associate the isotopic signatures to the main oceanographic forcings in the area. We recognized differences between the Nd and Pb sources for the sediments to the Argentinean shelf, carried by the Subantarctic Shelf Water, and slope, transported by deeper flows. Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper- and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate (up to 1,200 m water depth) areas, the transfer of sediments from the Argentinean margin to the North of 35° S is limited by the Subtropical Shelf Front and the recirculated Antarctic Intermediate Water. On the southern Brazilian margin, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. This influence is limited by the southward flow of waters transported by the Brazil Current. Finally, we propose that the Subtropical Shelf Front and the Santos Bifurcation act as boundaries of geochemical provinces in the area. Finally, a qualitative model of sediment sources and transport is provided for the Southwestern Atlantic margin.

scholarly journals Supplementary material to "Linking catchment hydrology and ocean circulation in Late Holocene southernmost Africa"

2016 ◽  
Author(s):  
Annette Hahn ◽  
Enno Schefuß ◽  
Sergio Andó ◽  
Hayley C. Cawthraw ◽  
Peter Frenzel ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Late Holocene ◽  
Catchment Hydrology ◽  
Supplementary Material

scholarly journals Mid-depth South Atlantic Ocean circulation and chemical stratification during MIS-10 to 12: implications for atmospheric CO<sub>2</sub>

2008 ◽  
Vol 4 (4) ◽  
pp. 333-344 ◽  
Author(s):  
A. J. Dickson ◽  
M. J. Leng ◽  
M. A. Maslin
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Sediment Cores ◽  
Convective Cell ◽  
Ocean Ventilation ◽  
Cape Basin ◽  
Northern Atlantic ◽  
Glacial Periods ◽  
Atlantic Margin

Abstract. A detailed record of benthic foraminifera carbon isotopes from the intermediate-depth South East Atlantic margin shows little glacial-interglacial variability between MIS-12 to MIS-10, suggesting that Northern Atlantic deepwaters consistently penetrated to at least 30° S. Millennial-scale increases in either the mass or flux of northern-sourced deepwaters over the core site occurred alongside reductions in Lower North Atlantic Deep Water recorded in North Atlantic sediment cores and show that the lower and intermediate limb of the Atlantic deepwater convective cell oscillated in anti-phase during previous glacial periods. In addition, a 500 yr resolution record of the Cape Basin intermediate-deep δ13C gradient shows that a reduction in deep Southern Ocean ventilation at the end of MIS-11 was consistent with a modelled CO2 drawdown of ~21–30 ppm. Further increases in the Southern Ocean chemical divide during the transition into MIS-10 were completed before minimum CO2 levels were reached, suggesting that other mechanisms such as alkalinity changes were responsible for the remaining ~45 ppm drawdown.

Supplementary material to "Surficial sediment texture database for SW Iberia Atlantic Margin"

2018 ◽  
Author(s):  
Susana Costas ◽  
Margarida Ramires ◽  
Luisa B. de Sousa ◽  
Isabel Mendes ◽  
Oscar Ferreira
Keyword(s):  
Surficial Sediment ◽  
Sediment Texture ◽  
Supplementary Material ◽  
Atlantic Margin

scholarly journals Mid-depth South Atlantic ocean circulation and chemical stratification during MIS-10 to 12: implications for atmospheric CO<sub>2</sub>

2008 ◽  
Vol 4 (3) ◽  
pp. 667-695 ◽  
Author(s):  
A. J. Dickson ◽  
M. J. Leng ◽  
M. A. Maslin
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Sediment Cores ◽  
Convective Cell ◽  
Intermediate Water ◽  
Ocean Ventilation ◽  
Cape Basin ◽  
Glacial Periods ◽  
Atlantic Margin

Abstract. A detailed record of benthic foraminifera carbon isotopes from the South East Atlantic margin shows little glacial-interglacial variability between MIS-12 to MIS-10, suggesting that Glacial North Atlantic Intermediate Water (GNAIW) consistently penetrated to at least 30° S. Millennial-scale increases in either the mass or flux of GNAIW over the core site occur alongside reductions in Lower North Atlantic Deep Water recorded in North Atlantic sediment cores and show that the lower and intermediate limb of the Atlantic deepwater convective cell oscillated in anti-phase during previous glacial periods. In addition, a 500 yr resolution record of the Cape Basin intermediate-deep δ13C gradient shows that a reduction in deep Southern Ocean ventilation at the end of MIS-11 was consistent with a modelled CO2 drawdown of ~21–30 ppm. Further increases in the Southern Ocean chemical divide during the transition into MIS-10 were completed before minimum CO2 levels were reached, suggesting that other mechanisms such as alkalinity changes were responsible for the remaining ~45 ppm drawdown.

scholarly journals Characterization of Nd Radiogenic Isotope Signatures in Sediments From the Southwestern Atlantic Margin

2018 ◽  
Vol 6 ◽  
Author(s):  
Simone S. Mantovanelli ◽  
Colombo C. G. Tassinari ◽  
Michel M. De Mahiques ◽  
Luigi Jovane ◽  
Everton Bongiolo
Keyword(s):  
Southwestern Atlantic ◽  
Radiogenic Isotope ◽  
Atlantic Margin

Dinoflagellate cyst zonation for the middle to upper Eocene in the Austral Basin, southwestern Atlantic Ocean: implications for regional and global correlation

2016 ◽  
Vol 154 (5) ◽  
pp. 1022-1036 ◽  
Author(s):  
M. SOL GONZÁLEZ ESTEBENET ◽  
G. RAQUEL GUERSTEIN ◽  
MARTÍN E. RODRÍGUEZ RAISING ◽  
JUAN J. PONCE ◽  
MARTA I. ALPERÍN
Keyword(s):  
Atlantic Ocean ◽  
Ocean Circulation ◽  
Regional Climate ◽  
Drake Passage ◽  
Late Eocene ◽  
Southwestern Atlantic ◽  
Dinoflagellate Cyst ◽  
South Pacific Ocean ◽  
Global Correlation ◽  
Southwestern Atlantic Ocean

AbstractThe well-exposed marine Eocene units from southwestern Patagonia, Argentina, contain useful information for reconstructing regional climate and oceanographic patterns in an area adjacent to the Drake Passage. The aim of this paper is to integrate dinoflagellate cyst data from three sections of the southwestern Austral Basin (Río Turbio Formation) to propose a zonation scheme, which can be applied to other southwestern Atlantic Ocean sites. Assemblages of organic walled dinoflagellate cysts have been analysed in different cropping-out sections and cores, showing the high potential of this fossil group as biostratigraphic markers. Comparison of dinoflagellate cyst events of the upper member of the Río Turbio Formation with calibrated biostratigraphic ranges in the Palaeogene South Pacific Ocean allowed us to date and correlate these sedimentary sections. The resulting zonation consists of four dinoflagellate cyst zones labelled RTF 1 to RTF 4, between the middle Lutetian and late Priabonian. As a final point, we applied dinoflagellate cyst species with importance as palaeoenvironmental markers to assess long-term climatic and oceanographic evolution for the area. This study shows that the endemic–Antarctic dinoflagellate cyst assemblage is dominant during the middle to late Eocene (RTF 1 to RTF 3), while a significant replacement of these taxa by cosmopolitan species characterizes the upper part of the upper member of the Río Turbio Formation (RTF 4). This turnover seems to be a consequence of changes in the ocean circulation patterns forced by deepening of the southern Atlantic gateways (the Drake Passage and the Tasman Gateway).

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