Micro-XANES mapping of sulphur and its association with magnesium and phosphorus in the shell of the brachiopod, Terebratulina retusa

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doi: 10.1016/j.chemgeo.2008.05.007
Authors:Cusack, M.; Dauphin, Y.; Cuif, Jean-Pierre; Salomé, Murielle; Freer, Andy; Yin, H.
Author Affiliations:Primary:
University of Glasgow, Department of Geographical and Earth Sciences, Glasgow, United Kingdom
Université Paris XI Orsay, France
European Synchrotron Radiation Facility, France
Volume Title:Chemical Geology
Source:Chemical Geology, 253(3-4), p.172-179. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541
Publication Date:2008
Note:In English. 73 refs.; illus.
Summary:Biominerals are natural composite materials comprising organic and inorganic components. Detailed knowledge of the nature and distribution of both components is a crucial requirement in order to advance our understanding of biomineral formation, their material properties and preservation potential as well as the interpretation of environmental data. Detailed chemical data are essential for our understanding of the nature and distribution of such components. Micro-XANES mapping at the sulphur K-edge reveals that, in the brachiopod Terebratulina retusa, the sulphate concentration is higher in the outer (primary) layer than in the calcite fibres of the secondary layer. This is co-incident with a higher magnesium concentration. In contrast, the sheaths surrounding the calcite fibres contain sulphur as thiol, confirming the presence of protein while, the sulphur within the fibres themselves, occurs as sulphate. Micro-XANES analysis of the insoluble organic extract from T. retusa indicates the presence of organic sulphate while Micro-Raman spectroscopy confirms that structurally substituted sulphate (SSS) is also present although semi-quantitative Raman spectroscopy carried out in this spectral region (wavenumbers 900-1200) indicates that the sulphate present is at the threshold of detection by Raman spectroscopy. The distribution of phosphorus in the shell of T. retusa correlates well with that of protein indicating the presence of phosphorylated proteins in the periostracum, the sheaths surrounding the calcite fibres and the interface between the primary and secondary layer. Abstract Copyright (2008) Elsevier, B.V. [D.J.M.]
Subsections:Organic geochemistry
Subjects:Alkaline earth metals; Articulata; Biochemistry; Biomineralization; Brachiopoda; Chemical composition; Magnesium; Metals; Phosphorus; Raman spectra; Shells; Spectra; Sulfur; Terebratulida; Terebratulina; X-ray diffraction data; X-ray spectra; XANES spectra; Atlantic Ocean; Europe; Great Britain; North Atlantic; Northeast Atlantic; Scotland; United Kingdom; Western Europe; Firth of Lorne; Invertebrata; Oban Scotland; Strathclyde region Scotland; Terebratulina retusa
Coordinates:N562400 N562400 W0053800 W0053800
Abstract Numbers:08M/3185
Record ID:2009023842
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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