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Deep-sea ostracode shell chemistry (Mg:Ca ratios) and late Quaternary Arctic Ocean history

Geological Society Special Publication

By:
, , , , and
Edited by:
Andrews J.T.et al
https://doi.org/10.1144/GSL.SP.1996.111.01.08

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Abstract

The magnesium:calcium (Mg:Ca) and strontium:calcium (Sr:Ca) ratios were investigated in shells of the benthic ostracode genus Krithe obtained from 64 core-tops from water depths of 73 to 4411 m in the Arctic Ocean and Nordic seas to determine the potential of ostracode shell chemistry for palaeoceanographic study. Shells from the Polar Surface Water (−1 to −1.5°C) had Mg:Ca molar ratios of about 0.006–0.008; shells from Arctic Intermediate Water (+0.3 to +2.0°C) ranged from 0.09 to 0.013. Shells from the abyssal plain and ridges of the Nansen, Amundsen and Makarov basins and the Norwegian and Greenland seas had a wide scatter of Mg:Ca ratios ranging from 0.007 to 0.012 that may signify post-mortem chemical alteration of the shells from Arctic deep-sea environments below about 1000 m water depth. There is a positive correlation (r2 = 0.59) between Mg:Ca ratios and bottom-water temperature in Krithe shells from Arctic and Nordic seas from water depths <900 m. Late Quaternary Krithe Mg:Ca ratios were analysed downcore using material from the Gakkel Ridge (water depths 3047 and 3899 m), the Lomonosov Ridge (water depth 1051 m) and the Amundsen Basin (water depth 4226 m) to test the core-top Mg:Ca temperature calibration. Cores from the Gakkel and Lomonosov ridges display a decrease in Mg:Ca ratios during the interval spanning the last glacial/deglacial transition and the Holocene, perhaps related to a decrease in bottom water temperatures or other changes in benthic environments.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Deep-sea ostracode shell chemistry (Mg:Ca ratios) and late Quaternary Arctic Ocean history
Series title:
Geological Society Special Publication
DOI:
10.1144/GSL.SP.1996.111.01.08
Volume:
111
Year Published:
1996
Language:
English
Publisher:
Geological Society
Description:
18 p.
First page:
117
Last page:
134
Public Comments:
This Geological Society Special Publication is a monograph titled Late Quaternary Palaeoceanography of the North Atlantic margins