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Article

Relationship between δ18O and minor element composition of Terebratalia transversa

Citation
Cusack M, Parkinson D, Pérez-Huerta A, England J, Curry GB & Fallick AE (2007) Relationship between δ18O and minor element composition of Terebratalia transversa. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 98 (3-4), pp. 443-449. https://doi.org/10.1017/S1755691008075671

Abstract
With their extensive fossil record and shells of stable low-Mg calcite, rhynchonelliform brachiopods are attractive sources of climate information via seawater temperature proxies such as stable oxygen isotope composition. In Terebratalia transversa (Sowerby) there is a progression towards oxygen isotope equilibrium in the calcite of the innermost secondary layer. This study confirms the lack of any vital effects influencing oxygen isotope composition of T. transversa, even in specialised areas of the innermost secondary layer. Calcite Mg/Ca ratio is another potential seawater temperature proxy, that has the advantage of not being influenced by salinity. Mg concentrations measured by electron microprobe analyses indicate that there is no concomitant decrease in Mg concentration towards the inner secondary layer, associated with the progressive shift towards oxygen isotope equilibrium. Mg distribution is heterogeneous throughout the shell and correlates with that of sulphur, which may be a proxy for organic components, suggesting that some of the Mg may not be in the calcite lattice. It is essential therefore, to determine the chemical environment of the magnesium ions to avoid any erroneous temperature extrapolations in brachiopods or any other calcite biomineral. 

Keywords
Brachiopods; calcite; magnesium; oxygen isotopes; sulphur; vital effect

Journal
Earth and Environmental Science Transactions of the Royal Society of Edinburgh: Volume 98, Issue 3-4

StatusPublished
Author(s)Cusack, Maggie; Parkinson, David; Pérez-Huerta, Alberto; England, Jennifer; Curry, Gordon B; Fallick, Anthony E
Publication date30/09/2007
Publication date online01/09/2007
Date accepted by journal24/07/2007
URLhttp://hdl.handle.net/1893/25064
PublisherCambridge University Press for Royal Society of Edinburgh
ISSN1755-6910
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