Shell size variation of Neogloboquadrina pachyderma sin. in the Norwegian-Greenland Sea during the last 1.3 Myr ...

• Main Authors: Huber, Robert, Meggers, Helge, Baumann, Karl-Heinz, Raymo, Maureen E, Henrich, Rüdiger
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2000
• Subjects: Composite Core; Leg104; Leg151; Leg162; Joides Resolution; Ocean Drilling Program ODP; Greenland; Greenland Sea; Neogloboquadrina pachyderma
• Online Access: https://dx.doi.org/10.1594/pangaea.704662; https://doi.pangaea.de/10.1594/PANGAEA.704662

We present measurements of the maximum diameter of the planktonic foraminifer Neogloboquadrina pachyderma sin. from six sediment cores (Ocean Drilling Program sites 643, 644, 907, 909, 985 and 987) from the Norwegian-Greenland Sea. Our data show a distinct net increase in mean shell size of N. pachyderma sin. at all sites during the last 1.3 Ma, with largest shell sizes reached after 0.4 Ma. External factors such as glacial-interglacial variability and carbonate dissolution alone cannot account for the observed variation in mean shell size of N. pachyderma sin. We consider the observed shell size increase to mirror an evolutionary trend towards better adaptation of N. pachyderma sin. to the cold water environment after 1.1-1.0 Ma. Probably, the Mid Pleistocene climate shift and the associated change of amplitude and frequency of glacial-interglacial fluctuations have triggered the evolution of this planktonic foraminifer. Oxygen and carbon stable isotope analyses of different shell size classes indicate that ... : For calcium carbonate concentrations see Huber et al. (2000b) data sets: doi:10.1594/PANGAEA.704663 ...