Mohan, Kuppusamy et al. (2011): Distribution of deep-sea benthic Foraminifera in the Neogene of Blake Ridge, NW Atlantic Ocean

Leg/Site/Hole:
ODP 164
ODP 164 991
ODP 164 994
ODP 164 995
ODP 164 997
Identifier:
2011-053969
georefid

10.1144/0262-821X10-008
doi

Creator:
Mohan, Kuppusamy
Indian Institute of Technology, Department of Geology and Geophysics, Kharagpur, India
author

Gupta, Anil K.
Indian School of Mines, India
author

Bhaumik, Ajoy K.
author

Identification:
Distribution of deep-sea benthic Foraminifera in the Neogene of Blake Ridge, NW Atlantic Ocean
2011
Journal of Micropalaeontology
British Micropalaeontological Society, London, United Kingdom
30
1
33-74
This study describes and illustrates the evolution of deep-sea benthic foraminifera from the Blake Ridge during the late Neogene. In total, 305 species of benthic foraminifera belonging to 107 genera were identified. The Blake Ridge receives fine-grained nannofossil-bearing hemipelagic sediments, transported from the Canadian continental margin by the Deep Western Boundary Undercurrent (DWBUC). We thus presume that changes in benthic foraminifera at Ocean Drilling Program (ODP) sites 991A, 994C, 995A and B and 997A reflect mainly changes in the intensity of the DWBUC, which is closely related to North Atlantic Deep Water (NADW) production. However, the dominance of Uvigerina peregrina, U. proboscidea and Cassidulina carinata during the late Miocene in all the holes suggests an increased influence of Southern Component Waters in the Blake Ridge region. During the early Pliocene (4.8-2.8 Ma) in all the sites benthic faunal assemblages suggest that there was an increased transport of organic-rich sediments by the DWBUC from the Canadian margin to the Blake Ridge, driven by increased production of NADW. During this time the species diversity (Sanders' rarefied values) was low. In the younger interval (since 2.8 Ma), the faunal data suggest less transport of organic-rich sediments to the Blake Ridge, which appears to be related to weakening of the DWBUC during cold intervals. An increase in species diversity at 3 Ma probably resulted from decreased population of bacteria due to low organic matter and/or less competition. In the late Pleistocene (c. 0.6 Ma), Stilostomella lepidula became extinct in all the studied holes, suggesting that this species may have possessed a mode of feeding which no longer existed in the cold, well-oxygenated oceans of the present.
English
Serial
Coverage:Geographic coordinates:
North:32.5901
West:-75.5548East: -75.2807
South:31.4708

Stratigraphy; Atlantic Ocean; benthic taxa; Blake-Bahama Outer Ridge; Cenozoic; deep-sea environment; faunal list; Foraminifera; Invertebrata; Leg 164; marine environment; microfossils; Neogene; North Atlantic; North Atlantic Deep Water; Ocean Drilling Program; ODP Site 991; ODP Site 994; ODP Site 995; ODP Site 997; paleo-oceanography; paleoecology; paleoenvironment; Protista; Tertiary;

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