thumbnail

Morphological variability of the planktonic foraminifer Neogloboquadrina pachyderma from ACEX cores: Implications for late pleistocene circulation in the Arctic Ocean

Micropaleontology

By:
, , , , , , , and

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

Planktonic foraminifera populations were studied throughout the top 25 meters of the IODP ACEX 302 Hole 4C from the central Arctic Ocean at a resolution varying from 5cm (at the top of the record) to 10cm. Planktonic foraminifera occur in high absolute abundances only in the uppermost fifty centimetres and are dominated by the taxa Neogloboquadrina pachyderma. Except for a few intermittent layers below this level, most samples are barren of calcareous microfossils. Within the topmost sediments, Neogloboquadrina pachyderma specimens present large morphological variability in the shape and number of chambers in the final whorl, chamber sphericity, size, and coiling direction. Five morphotypes were identified among the sinistral (sin.) population (Nps-1 to Nps-5), including a small form (Nps-5) that is similar to a non-encrusted normal form also previously identified in the modern Arctic Ocean water masses. Twenty five percent of the sinistral population is made up by large specimens (Nps-2, 3,4), with a maximal mean diameter larger than 250??m. Following observations made in peri-Arctic seas (Hillaire-Marcel et al. 2004), we propose that occurrence of these large-sized specimens of N. pachyderma (sin.) in the central Arctic Ocean sediments could sign North Atlantic water sub-surface penetration.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Morphological variability of the planktonic foraminifer Neogloboquadrina pachyderma from ACEX cores: Implications for late pleistocene circulation in the Arctic Ocean
Series title:
Micropaleontology
Volume
55
Issue:
2-3
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Micropaleontology
First page:
101
Last page:
116
Number of Pages:
16