Mg/Ca composition of benthic foraminifera Miliolacea as a new tool of paleoceanography

Aleksey Yu Sadekov, Flora Bush, Joanna Kerr, Raja Ganeshram, Henry Elderfield

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The Mg/Ca compositions of benthic foraminifera from the superfamily Miliolacea have been studied to explore the use of these high-Mg foraminifera as a proxy for deep ocean conditions. Taxonomic analyses, relative abundance, and depth distributions of different Miliolacea species were carried out on a collection of core top samples, covering a depth range of 131m to 2530m, along the Australian coast of the Timor Sea. Pyrgo sp., composed of Pyrgo sarsi and Pyrgo murrhina, was found to be the most suitable for proxy studies. Mg/Ca values of this group of foraminifera show a strong correlation with bottom water temperatures and carbonate ion saturation described by the linear relationship: Mg/Ca=2.53(±0.22)×BWT+0.129(±0.023)×Δ[CO32-]+4.63(±0.53), within the -1C to 8C temperature range. Absolute Mg/Ca values of Pyrgo sp. calcite and their temperature sensitivity are similar to those observed for inorganic calcite, suggesting that Mg composition of Pyrgo sp. calcite is mainly controlled by inorganic processes. The Mg/Ca composition of Pyrgo sp. calcite provides a new tool for reconstructing both water temperature and carbonate ion saturation when combined with other proxies for one of these parameters. A down core record from the Eastern Equatorial Pacific has been generated to illustrate how Mg/Ca values can be used for paleoclimate studies. This down core record shows large changes in Pacific bottom waters [CO32-] across glacial-interglacial transition, implying an increase in [CO32-] during the glacial period. Key Points Miliolacea, high-Mg foraminifera as a proxy for deep ocean conditionsMg/Ca values correlate with water temperatures and carbonate ion saturationMg composition of Pyrgo sp. calcite is mainly controlled by inorganic processes

Original languageEnglish
Pages (from-to)990-1001
Number of pages12
JournalPaleoceanography
Volume29
Issue number10
DOIs
Publication statusPublished - 1 Oct 2014
Externally publishedYes

Fingerprint

paleoceanography
benthic foraminifera
calcite
foraminifera
water temperature
carbonate
bottom water
ion
saturation
ocean
paleoclimate
interglacial
vertical distribution
relative abundance
temperature
coast

Cite this

Sadekov, Aleksey Yu ; Bush, Flora ; Kerr, Joanna ; Ganeshram, Raja ; Elderfield, Henry. / Mg/Ca composition of benthic foraminifera Miliolacea as a new tool of paleoceanography. In: Paleoceanography. 2014 ; Vol. 29, No. 10. pp. 990-1001.
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Mg/Ca composition of benthic foraminifera Miliolacea as a new tool of paleoceanography. / Sadekov, Aleksey Yu; Bush, Flora; Kerr, Joanna; Ganeshram, Raja; Elderfield, Henry.

In: Paleoceanography, Vol. 29, No. 10, 01.10.2014, p. 990-1001.

Research output: Contribution to journalArticle

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