Isotope characterisation of historical alabaster quarries in Western Europe
Abstract
The origin of the raw material of gypsum alabaster artwork is still largely underinvestigated as conventional chem-
ical 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
16 th 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 histor-
ical 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 14thto 16thcentury from
the Louvre Museum, Cleveland Museum of Fine Arts, the Petit Palais Museum in Avignon and several regional
collections and monuments
Domains
Geochemistry
Origin : Files produced by the author(s)