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Journal of Micropalaeontology An open-access journal of The Micropalaeontological Society
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Volume 9, issue 2
J. Micropalaeontol., 9, 133–143, 1991
https://doi.org/10.1144/jm.9.2.133
© Author(s) 1991. This work is distributed under
the Creative Commons Attribution 4.0 License.
J. Micropalaeontol., 9, 133–143, 1991
https://doi.org/10.1144/jm.9.2.133
© Author(s) 1991. This work is distributed under
the Creative Commons Attribution 4.0 License.

  01 Mar 1991

01 Mar 1991

Palaeoclimatic control of Upper Pliocene Discoaster assemblages in the North Atlantic

Alex Chepstow-Lusty1, Jan Backman2, and Nicholas J. Shackleton1 Alex Chepstow-Lusty et al.
  • 1Godwin Laboratory, Subdepartment of Quaternary Research, University of Cambridge, Cambridge CB2 3RS
  • 2Department of Geology, University of Stockholm, S-106 91 Stockholm

Abstract. Abundance variations of six Pliocene species of the nannofossil genus Discoaster were analyzed over the time interval 1.89–2.95 Ma at five sites in the North Atlantic; DSDP 552 (56°N), DSDP 607 (41°N), ODP 659 (18°N), ODP 658 (20°N) and ODP 662 (1°S). Individual species are compared between the five sites as a percentage of the total Discoaster assemblage, using age models based mainly on Discoaster datums (3 control points used at each site). The sampling interval is approximately 3 kyrs.

Discoaster brouweri, the only species covering the complete time interval became a less significant component of the assemblages with increasing latitude during the interval prior to 2.3 Ma. Discoaster triradiatus shows a distinct abundance acme at all sites between 1.89–2.7 Ma. Discoaster surculus increased in relative abundance with higher latitudes and upwelling conditions (ODP Site 658).

Discoaster pentaradiatus is an important component of the assemblages at all sites, but displays an inverse abundance relationship with D. surculus as a function of increasing latitude and upwelling conditions. Discoaster tamalis and Discoaster asymmetricus are reduced at low latitudes and in upwelling conditions and increase relative to D. brouweri at higher latitudes, where there is strong evidence for taxonomic affinity.

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