Radionuclides of surface sediments and water samples in the South Atlantic south of the Polar Front ...

The fractionation of 230Th and 231Pa was investigated throughout the Atlantic sector of the Southern Ocean. Published scavenging models generally assume that the 231Pa/230T ratio of surface sediments is primarily determined by the mass flux of particles. This relationship holds north of the Polar Fr...

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Bibliographic Details
Main Authors: Walter, Hans-Jürgen, Rutgers van der Loeff, Michiel M, Hoeltzen, H
Format: Article in Journal/Newspaper
Language:English
Published: PANGAEA 1997
Subjects:
MultiCorer
MiniCorer
Giant box corer
CTD/Rosette
In situ pump
Piston corer BGR type
ANT-VIII/3
ANT-IX/2
ANT-IX/3
ANT-X/5
ANT-X/6
ANT-XI/4
Polarstern
Marine Geochemistry @ AWI AWI_MarGeoChem
Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo
Southern Ocean
Weddell
Weddell Sea
Online Access:https://dx.doi.org/10.1594/pangaea.730455
https://doi.pangaea.de/10.1594/PANGAEA.730455
Description
Summary:The fractionation of 230Th and 231Pa was investigated throughout the Atlantic sector of the Southern Ocean. Published scavenging models generally assume that the 231Pa/230T ratio of surface sediments is primarily determined by the mass flux of particles. This relationship holds north of the Polar Front, where low primary productivity coincides with ratios of unsupported 231Pa/230Th-xs(231Pa/230Th) - in surface sediments below the production ratio of both radionuclides in the water column. However, we observed high xs231Pa/230Th ratios, conventionally interpreted as a high-productivity signal, in surface sediments south of the Polar Front, especially throughout the Weddell Sea, in contradiction with the low particle flux of this region. Measurements of both dissolved and particulate fractions of 231Pa and 230Th in the water column revealed a strong N-S decrease in the Th/Pa fractionation factor, from typical open ocean values around 10 north of the Polar Front to values between 1 and 2 south of 60°S. This ... : Supplement to: Walter, Hans-Jürgen; Rutgers van der Loeff, Michiel M; Hoeltzen, H (1997): Enhanced scavenging of 231Pa relative to 230 Th in the South Atlantic south of the Polar Front: implications for the use of the 231Pa/230Th ratio as a paleoproductivity proxy. Earth and Planetary Science Letters, 149(1-4), 85-100 ...

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