New data on the cathodoluminescence of white marbles : Interpretation of peaks and relationships to weathering
Part of : Mediterranean archaeology & archaeometry : international journal ; Vol.10, No.4, 2010, pages 107-114
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107-114
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Abstract:
This work focus on the Thermoluminescence (TL), the Spatially Resolved Spectral Cathodoluminescence(CL) and Raman spectroscopy (Raman) of white marble specimens collected from the archaeologicalpark of Aiani (Greece) and from patterns of Iceland calcite and Macael marble forcomparison purposes. The spectra CL were measured with a high sensitivity cathodoluminescencespectrometer MonoCL3 of Gatan (UK) attached to an FEI‐ESEM microscope (CL‐ESEM). The experimentalset of spectra CL curves of Aiani white marbles suggest that the blue band is more resistantto weathering in comparison with the red band which drops down easily under weathering.The comparison among CL spectra of CaCO3 patterns give a slight difference between the small 330nm peak, detected in marble and not observed in the monocrystal pattern of Iceland calcite. TheBackscattering Electron Dispersed (BSED) images of the white marble are similar to the CL monochromaticplots at 330 nm which highlight the surfaces with remarkable clarity, suggesting a CLemission‐defect associated to the marble crystal interfaces, such as protons or hydroxyls. Conversely,the 395 nm monochromatic mapping depicts a CL image emitting from bulk and not frominterfaces attributable to point defects or cationic activators in Ca2+ positions. The blue band of thespectra luminescence of marble is composed by several peaks associated to very different types ofluminescent defects. This statement is not inconsequential since in archaeological TL dating of marblesthe regenerated luminescence in the blue region of the spectrum is a serious difficulty and furtherresearch on this topic is necessary.
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Keywords:
Marble, Cathodoluminescence, Raman, Thermoluminescence, 330 nm, Aiani
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