Cathodoluminescence and Laser-Induced Fluorescence of Calcium Carbonate: A Review of Screening Methods for Radiocarbon Dating of Ancient Lime Mortars

Toffolo, Michael B.; Ricci, Giulia; Chapoulie, Rémy; Caneve, L.; Kaplan‐Ashiri, Ifat

doi:10.1017/rdc.2020.21

Cited by 16 publications

(14 citation statements)

References 69 publications

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“…A NIKON Labophot2-POL petrographic microscope (Nikon, Tokyo, Japan) equipped with a cold cathode stage Cambridge Image Technology Ltd. (Hatfield, UK), CL8200 MK3 operated at a voltage of 15 kV, and a current of 250 µA was used. OM-CL can be considered a complementary luminescence technique [2,53] and allows optical examination performing imaging analysis in real-time "true colours" in the visible range.…”

Section: Methodsmentioning

confidence: 99%

Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Ricci

Monti

Pagano³

et al. 2021

Minerals

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Quartz from La Sassa (Tuscany, Italy) presents a unique luminescence related to intrinsic and extrinsic defects in the crystal lattice due to the growth mechanisms in hydrothermal conditions. The bright fluorescence under the UV lamp was apparent to collectors since the early 1970s, and it entered the literature as a reference case of yellow-luminescent quartz. Early reports present the history of the discovery, the geological context, and preliminary luminescence measurements of the quartz nodules, suggesting various activators as potentially responsible of the peculiar luminescence effects: uranyl groups (UO22+), rare earths (Tb3+, Eu3+, Dy3+, Sm3+, Ce3+) and polycyclic aromatic compounds (PAH). Here, we report a full investigation of the La Sassa material, by a multi-analytical approach encompassing cathodoluminescence optical microscopy (OM-CL), laser-induced fluorescence (LIF), wavelength resolved thermally stimulated luminescence (WR-TSL), trace elements analysis by mass spectrometry (ICP-MS) and Raman spectroscopy (RS). The results provide a significant step forward in the interpretation of the luminescence mechanisms: the main luminescent centres are identified as alkali-compensated (mainly Li+ and Na+, K+ and H+) aluminum [AlO4/M+]0 centres substituting for Si, where the recombination of a self-trapped exciton (STE) or an electron at a nonbridging oxygen hole centre (NBOHC) are active.

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Section: Methodsmentioning

confidence: 99%

Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Ricci

Monti

Pagano³

et al. 2021

Minerals

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“…Of the above mentioned 7 common white pigments, kaolinite, calcite and zinc oxide have been studied in the past using SEM/CL [44][45][46][47][48]. The detailed analysis of these 7 samples suggests that they all present CL spectra with characteristic bands, as shown in the following figures.…”

Section: Characteristic CL Spectramentioning

confidence: 99%

“…1). The common defects of geological calcitic material have been discussed in detail in literature [46,47].…”

Section: Characteristic CL Spectramentioning

confidence: 99%

Towards building a Cathodoluminescence (CL) database for pigments: characterization of white pigments

Palamara

Das²,

Nicolopoulos³

et al. 2021

Herit Sci

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Paintings and painted surfaces are considered to be extremely complex due to their multitude of materials and thus form the basis for particularly intricate Cultural Heritage studies. The combination of Scanning Electron Microscopy (SEM) with Cathodoluminescence (CL) can serve as a powerful tool for the identification of individual pigments. SEM/CL has the potential of identifying both organic and inorganic pigments and can focus on a micrometer or even nanometer scale. The combination with Energy Dispersive Spectrometry (EDS) allows for robust, cross-checked, elemental and mineralogical characterization of pigments. In order to apply SEM/CL in a routine-based way for the identification of pigments, it is necessary to have a robust, open-access database of characteristic CL spectra of pigments. A large project has been undertaken to create such a database, focusing primarily at the pigments, both organic and inorganic, which were most commonly used from antiquity until today. In the present paper, the CL characterization of common white pigments is presented. White pigments were selected, due to their significance and frequency of use, since they were also present on the ground layers or mixed with other pigments in most of the painting layers. More specifically, the CL spectra of samples in pure form of calcite, kaolinite, lead white, zinc oxide, barium sulfate, lithopone and titanium white are presented. In all cases, the CL spectra present characteristic bands, which allow for a secure identification of the pigments. In order to facilitate comparison with other databases, EDS and RAMAN spectra are also presented. Additionally, the effect of weathering on the CL spectra was evaluated, by comparison to naturally and artificially aged samples and to pigments identified on areas of two paintings, of the 19th and 20th c., respectively. Finally, the effect of binding media was also studied, using combination of pigments with four common media: egg yolk, linseed, walnut and poppy oil. Overall, both weathering and binding media appear to cause minor differences in the occurring spectra, without preventing the identification of pigments.

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“…The same method allows the analysis of calcite, which instead might in part derive from the recrystallization of aragonite into calcite. Additionally, SEM‐CL can identify pristine pyrogenic aragonite and calcite based on the emission of blue luminescence, whereas orange luminescence is indicative of Ca 2+ substitution by Mn 2+ and thus of diagenesis (Toffolo, Regev, et al, 2020; Toffolo, Ricci, Chapoulie, Caneve, & Kaplan‐Ashiri, 2020; Toffolo, Ricci, et al, 2019; Wendler, Wendler, Rose, & Huber, 2012; Figure 6).…”

Section: Archaeological Significancementioning

confidence: 99%

The significance of aragonite in the interpretation of the microscopic archaeological record

Toffolo

2020

Geoarchaeology

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Aragonite is one of the metastable polymorphs of calcium carbonate and is commonly found at archaeological sites in the form of mollusk shells and speleothems. Other occurrences include corals, fish otoliths, seed endocarps, wood ash, and lime plaster. These materials contain microscopic embedded information of fundamental importance for the assessment of the state of preservation of the archaeological record, the reconstruction of paleoenvironments, the identification of pyrotechnological processes, and the establishment of absolute chronologies. However, this information can be used only if the aragonite found at archaeological sites preserves its pristine structure and chemistry. Aragonite is metastable at ambient conditions and tends to dissolve and recrystallize into secondary aragonite or calcite, a process that entails the loss of its original elemental and isotopic signature. Therefore, well‐grounded archaeological interpretations depend on the correct identification of aragonite and the careful characterization of its basic properties. This article reviews the dissolution processes of different types of aragonite, the methods used for their identification, and the archaeological information that can be extracted. Particular emphasis is given to the discussion of key issues regarding absolute dating and postdepositional processes of archaeological sediments, and to a detailed overview of the recently observed pyrogenic aragonite.

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Cathodoluminescence and Laser-Induced Fluorescence of Calcium Carbonate: A Review of Screening Methods for Radiocarbon Dating of Ancient Lime Mortars

Cited by 16 publications

References 69 publications

Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Towards building a Cathodoluminescence (CL) database for pigments: characterization of white pigments

The significance of aragonite in the interpretation of the microscopic archaeological record

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