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Early Maastrichtian benthic foraminiferal assemblages from the western North Atlantic (Blake Nose) and their relation to paleoenvironmental changes

Early Maastrichtian benthic foraminiferal assemblages from the western North Atlantic (Blake Nose) and their relation to paleoenvironmental changes
Early Maastrichtian benthic foraminiferal assemblages from the western North Atlantic (Blake Nose) and their relation to paleoenvironmental changes
Benthic foraminiferal faunas from the Lower Maastrichtian (Globotruncana falsostuarti–Gansserina gansseri Planktic Foraminiferal Zone) of DSDP Site 390 (Blake Nose, western North Atlantic) were investigated in order to characterize changes in organic matter flux and bottom-water oxygenation and their relation to paleoceanographic changes. Benthic foraminiferal faunas in the lower part of the studied succession show high abundances of Praebulimina reussi and Nuttallides truempyi and are proposed to reflect fluctuations in organic matter flux to the seafloor (meso- to eutrophic) under oxygenated bottom-water conditions. The middle interval is characterized by very low numbers of benthic foraminiferal specimens but a dominance of thick-walled species (e.g., lenticulinids, laevidentalinids), may reflect carbonate dissolution. In contrast to the lower part, benthic foraminifera from the upper part of the succession show well-oxygenated bottom waters. The most dominant species during this interval are Gavelinella beccariiformis, Reussella szajnochae, and N. truempyi. Parallel to this change in the benthic foraminiferal assemblages the number of inoceramid shells decreases, reflecting a significant increase in bottom-water oxygenation. Based on these data we speculate, that the observed changes in benthic foraminiferal assemblages towards a well-oxygenated environment within the Early Maastrichtian of DSDP Site 390 could reflect the onset of a shift from low-latitude to high-latitude deep-water sources. This speculation will predate the major reorganization of the oceanic circulation resulting in a circulation mode similar to today at the Early/Late Maastrichtian boundary by 1 Ma.
Cretaceous, ocean circulation, North Atlantic, benthic foraminifera, Maastrichtian
0377-8398
31-44
Friedrich, O.
219eb084-560e-4c36-b2f5-b33a8b582c33
Hemleben, C.
0f45ede4-dfec-457e-8a64-b96a5b8c71f0
Friedrich, O.
219eb084-560e-4c36-b2f5-b33a8b582c33
Hemleben, C.
0f45ede4-dfec-457e-8a64-b96a5b8c71f0

Friedrich, O. and Hemleben, C. (2007) Early Maastrichtian benthic foraminiferal assemblages from the western North Atlantic (Blake Nose) and their relation to paleoenvironmental changes. Marine Micropaleontology, 62 (1), 31-44. (doi:10.1016/j.marmicro.2006.07.003).

Record type: Article

Abstract

Benthic foraminiferal faunas from the Lower Maastrichtian (Globotruncana falsostuarti–Gansserina gansseri Planktic Foraminiferal Zone) of DSDP Site 390 (Blake Nose, western North Atlantic) were investigated in order to characterize changes in organic matter flux and bottom-water oxygenation and their relation to paleoceanographic changes. Benthic foraminiferal faunas in the lower part of the studied succession show high abundances of Praebulimina reussi and Nuttallides truempyi and are proposed to reflect fluctuations in organic matter flux to the seafloor (meso- to eutrophic) under oxygenated bottom-water conditions. The middle interval is characterized by very low numbers of benthic foraminiferal specimens but a dominance of thick-walled species (e.g., lenticulinids, laevidentalinids), may reflect carbonate dissolution. In contrast to the lower part, benthic foraminifera from the upper part of the succession show well-oxygenated bottom waters. The most dominant species during this interval are Gavelinella beccariiformis, Reussella szajnochae, and N. truempyi. Parallel to this change in the benthic foraminiferal assemblages the number of inoceramid shells decreases, reflecting a significant increase in bottom-water oxygenation. Based on these data we speculate, that the observed changes in benthic foraminiferal assemblages towards a well-oxygenated environment within the Early Maastrichtian of DSDP Site 390 could reflect the onset of a shift from low-latitude to high-latitude deep-water sources. This speculation will predate the major reorganization of the oceanic circulation resulting in a circulation mode similar to today at the Early/Late Maastrichtian boundary by 1 Ma.

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More information

Published date: 10 January 2007
Keywords: Cretaceous, ocean circulation, North Atlantic, benthic foraminifera, Maastrichtian

Identifiers

Local EPrints ID: 49994
URI: http://eprints.soton.ac.uk/id/eprint/49994
ISSN: 0377-8398
PURE UUID: 8910299b-f0f2-4ee9-9269-f638a19eef32

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Date deposited: 08 Jan 2008
Last modified: 15 Mar 2024 10:01

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Author: O. Friedrich
Author: C. Hemleben

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