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Marine Biology

, Volume 142, Issue 2, pp 299–304 | Cite as

In situ mapping of growth lines in the calcitic prismatic layers of mollusc shells using X-ray absorption near-edge structure (XANES) spectroscopy at the sulphur K-edge

  •  Y. Dauphin
  •  J. Cuif
  •  J. Doucet
  •  M. Salomé
  •  J. Susini
  •  C. Williams

Abstract.

The microstructure and composition, including chemical speciation of sulphur (S), of two mollusc shells were investigated using a combination of scanning electron microscopy, X-ray absorption near-edge structure spectroscopy (XANES) and electron probe microanalysis (EPMA). The shell of Pinna is composed of monocrystalline, and Pinctada, of polycrystalline, calcite prisms separated by organic-rich walls. Sulphur speciation information from XANES spectra using a scanning X-ray microscope showed that the protein S content of the interprismatic walls is higher than the SO4 content, whereas the reverse is true for the intraprismatic structures. High-spatial-resolution XANES maps for the different S species across adjacent calcite prisms confirm their distinctive distributions in the molluscan shells and illustrate the presence of narrow, submicron transverse growth features. On a larger scale, a series of wider growth zones, incorporating the submicron zones, are aligned parallel to each other and cross-cut many calcite prisms. EPMA element maps for magnesium (Mg) and S demonstrate that these growth increments are compositionally zoned, comprising alternating layers of high mineral (Mg-rich) and high organic (S-rich) components. Additionally, these maps confirm that the organic interprismatic walls have lower Mg and higher S than the intraprismatic structures.

Keywords

Electron Probe Microanalysis Growth Increment Growth Line Sulphur Speciation Mollusc Shell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  •  Y. Dauphin
    • 1
  •  J. Cuif
    • 1
  •  J. Doucet
    • 2
  •  M. Salomé
    • 3
  •  J. Susini
    • 3
  •  C. Williams
    • 4
  1. 1.Laboratoire de paléontologie, FRE2566 du CNRS, Bâtiment 504, Université Paris XI–Orsay, 91405 Orsay cedex, France
  2. 2.LURE, Bâtiment 209D, BP 34, Université Paris XI–Orsay, 91898 Orsay cedex, France
  3. 3.ID21, ESRF, BP 220, 38043 Grenoble cedex, France
  4. 4.Department of Mineralogy, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK

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