Distribution of benthic foraminifera with related sedimentological hydrographic parameter in the eastern Weddell Sea, Antarctica
Surface sediment samples taken with a vented box corer from the eastern Weddell Sea on four profiles perpendicular to the continental margin have been investigated for their benthic foraminiferal content. The live fauna was differentiated from empty tests comprising the foraminiferal death assemblag...
| Main Authors: | , , , |
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| Format: | Dataset |
| Language: | English |
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PANGAEA
1990
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| Subjects: | |
| Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.552126 https://doi.org/10.1594/PANGAEA.552126 |
| Summary: | Surface sediment samples taken with a vented box corer from the eastern Weddell Sea on four profiles perpendicular to the continental margin have been investigated for their benthic foraminiferal content. The live fauna was differentiated from empty tests comprising the foraminiferal death assemblage. Based on the dead assemblages, potential fossil assemblages were calculated to facilitate the analogy with late Neogene core material. Five distinct live assemblages inhabit the continental margin today. Six dead assemblages and five potential fossil assemblages, respectively, correspond to these biocoenoses. A predominantly calcareous live fauna dominated byTrifarina angulosa is correlated with strong bottom currents and sandy sediments at the shelf break and on the uppermost continental slope. Below this, on the upper slope down to 2000 m water depth, the predominantly calcareousBulimina aculeata assemblage coincides with the core of warm (>0°C) Weddell Deep Water and with fine and more organic-rich sediments. These calcareous live assemblages completely change composition during early diagenesis because of calcite dissolution within the uppermost sediment, which depends largely on the grain size distribution of the sediment and the fluxes of organic matter. Therefore, a still calcareousT. angulosa-dominated fossil assemblage indicates the sandy substrates on the shelf break and the upper slope, whereas the deeper slope with hemipelagic calm sedimentation and with high fluxes of organic matter is indicated byMartinottiella nodulosa, the characteristic arenaceous fossil remnant of the former predominantly calcareous liveB. aculeata fauna. On a continental terrace between 2500 and 3500 m water depthCribrostomoides subglobosus dominates the live fauna, but because of rapid disintegration of the empty tests of this agglutinated species a predominantly calcareous fauna characterized byOridorsalis umbonatus andEpistominella exigua comprises the dead assemblage and the potential fossil assemblage, respectively. On ... |
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