Miocene deepwater agglutinated foraminifera from the Lomonosov Ridge and opening of the Fram Strait

ABSTRACT: Deep-water agglutinated Foraminifera (DWAF) are investigated from Miocene sediments recovered from ODP Hole 909C in the Fram Strait, Norwegian-Greenland Sea. We studied 125 samples from Cores 909C-50R to –103R, and recovered over 60 species of DWAF. The faunal succession in Hole 909C is su...

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Bibliographic Details
Main Authors: Michael A. Kaminski, Lóránd Silye, Severyn Kender
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 2009
Subjects:
Arctic
Arctic Ocean
Greenland
Norwegian Sea
Foraminifera*
Fram Strait
Greenland Sea
Lomonosov Ridge
North Atlantic
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.496.3353
http://www.ucl.ac.uk/EarthSci/people/m-kaminski/reprints-pdfs/Micropaleo_51_5_373-403.pdf
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Summary:ABSTRACT: Deep-water agglutinated Foraminifera (DWAF) are investigated from Miocene sediments recovered from ODP Hole 909C in the Fram Strait, Norwegian-Greenland Sea. We studied 125 samples from Cores 909C-50R to –103R, and recovered over 60 species of DWAF. The faunal succession in Hole 909C is subdivided into three assemblages based on the stratigraphic ranges of charac-teristic cosmopolitan taxa. These are: (1) a diverse Reticulophragmium amplectens – Reophanus berggreni Assemblage in Cores 909C-100R-2 to-91R-1 (1040.71–952.78mbsf); (2) a Reticulophragmium amplectens Assemblage in Cores 909C-87R-2, to-71R-3 (915.7–762.68mbsf); and (3) a low-diversity Reticulophragmium rotundidorsatum Assemblage in Cores 909C-71R-1 to-55R-1 (759.68-605.52mbsf). The DWAF assemblages are correlated to the standard chronostratigraphy using dinoflagellate cysts and magnetostratigraphy. The stratigraphic ranges of some well-known Paleogene DWAF species extend far into the Miocene at this local-ity, confirming the hypothesis that the Arctic and northern Norwegian Sea basins served as a refuge for these species long after they dis-appeared from the North Atlantic stratigraphic record. The taxonomic affinities of the Miocene assemblages from Hole 909C supports the idea that an estuarine circulation pattern has been in place between the Arctic Ocean and Greenland Sea basins since at least the early Miocene. Changes in the benthic foraminiferal morphogroups within the R. rotundidorsatum Assemblage correlate with an increase in total organic carbon, indicating an increase in oceanic productivity in the Fram Strait region during the late Miocene.

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