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| Titel |
Isotope characterisation of historical alabaster quarries in Western Europe. |
| VerfasserIn |
Wolfram Kloppmann, Lise Leroux, Philippe Bromblet, Anthony H. Cooper, Angela Nestler, Catherine Guerrot, Anne-Thérèse Montech, Noel Worley |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250106228
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| Publikation (Nr.) |
 EGU/EGU2015-5888.pdf |
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| Zusammenfassung |
| The origin of the raw material of gypsum alabaster artwork is still largely underinvestigated
as conventional chemical and mineralogical analyses have not yielded convincing results
due to the rather homogeneous composition, especially of the most wanted pure
white varieties. Yet, identifying the origin of raw materials used for sculpture is
crucial for art historians and museums aiming at identifying artists, rarely nominally
documented before the 16th century, workshops and historic trade roads. A pilot study
(Kloppmann et al., 2014) revealed the potential of multi-isotope fingerprinting of alabaster
provenance, using a combination of sulphur, oxygen and strontium isotopes. Here
we present an enlarged data base of isotope analyses of samples from known or
suspected historical alabaster exploitations in France (Jura, Alps, Provence, Burgundy,
Lorraine, Aquitaine, Paris region), Spain (Aragon and Catalonia), England (East
Midlands/Nottingham region, Cumberland, N Yorkshire), Germany (Harz Mountain
foreland). Strontium and sulphur isotopes appear to be particularly discriminative
with a strong inter-site variability and intra-site homogeneity. Isotope ratios of both
elements in seawater and associated evaporites have strongly varied over geological
timescales (Claypool et al. 1980; Burke et al. 1982; Denison et al. 1998) so that
W-European alabaster samples, ranging from Permian (Zechstein) to Miocene ages, show
age-specific differentiation. Additionally, for both elements, non-marine sources
such as sulphides, organic sulphur and strontium derived from mineral weathering
provide basin- or sub-basin-specific signatures that further discriminate alabaster
provenances. Oxygen isotopes provide supplementary evidence even if there is a
stronger overlap of signatures. In conclusion, we consider that we have now an
operational tool to distinguish the main alabaster sources for historical workshops
in Western Europe. This methodology is currently applied to sculptures ranging
from the 14th to 16th century from the Louvre Museum, Cleveland Museum of
Fine Arts, the Petit Palais Museum in Avignon and several regional collections and
monuments.
Burke W. H., Denison R. E., Hetherington E. A., Koepnick R. B., Nelson H. F., and Otto
J. B. (1982) Variation of seawater 87Sr/86Sr throughout Phanerozoic time. Geology 10,
516-519.
Claypool G. E., Holser W. T., Kaplan I. R., Sakai H., and Zak I. (1980) The age curves of
sulfur and oxygen isotopes in marine sulfate and their mutual interpretation. Chem. Geol. 28,
199-260.
Denison R. E., Kirkland D. W., and Evans R. (1998) Using strontium isotopes to
determine the age and origin of gypsum and anhydrite beds. J. Geol. 106, 1-17.
Kloppmann W., Leroux L., Bromblet P., Guerrot C., Proust E., Cooper A. H., Worley N.,
Smeds S. A., and Bengtsson H. (2014) Tracing Medieval and Renaissance Alabaster Works
of Art Back to Quarries: A Multi-Isotope (Sr, S, O) Approach. Archaeometry 56, 203-219. |
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