Significance of variability in Turborotalita quinqueloba (Natland) test size and abundance for paleoceanographic interpretations in the Norwegian-Greenland Sea

• Published in: Marine Geology
• Main Author: Bauch, Henning A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 1994
• Subjects: Greenland; Vøring Plateau; Greenland Sea
• Online Access: https://oceanrep.geomar.de/id/eprint/27859/; https://oceanrep.geomar.de/id/eprint/27859/1/1994_Bauch-Significance_MarGeol-121.pdf; https://doi.org/10.1016/0025-3227(94)90162-7

Biometric analyses on shells of Turborotalita quinqueloba (Natland) reflect the paleoceanographic conditions in the Norwegian-Greenland Sea (NGS). Both median and mean size variations exhibit a steady increase after the Last Glacial Maximum (LGM). After Termination I the size eventually reaches a constant level with only minor fluctuation. In contrast, peak abundances of specimens occur somewhat later, during the Holocene climatic optimum and rapidly decrease again in the youngest sediments. Test sizes are larger at the Vøring Plateau in the vicinity of incoming Atlantic water than in water further to the west. Turborotalita quinqueloba first appeared in the southwestern part of the NGS with a preliminary major peak in abundance and size well below the Younger Dryas. This species was present in sizes < 125 μm in this area during almost entire oxygen isotopic Stage 2. This was not observed in the more easterly located cores. It seems likely that size variations as a ‘tool’ for NGS paleoceanographic interpretations are not only valuable for the time since the LGM, but can also be applied to older isotopic stages where abundances of T. quinqueloba are low or absent in the > 125 μm size-fractions but are high in the 63–125 μm fraction (e.g. Stages 7, 9 and 11).