Dolomitic Marble from Thasos at the Louvre Thomas Calligaro, Yvan Coquinot, Maria Guerra, John Herrmann, Ludovic Laugier, Annewies Van Den Hoek
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Dolomitic marble from Thasos at the Louvre Thomas Calligaro, Yvan Coquinot, Maria Guerra, John Herrmann, Ludovic Laugier, Annewies van den Hoek To cite this version: Thomas Calligaro, Yvan Coquinot, Maria Guerra, John Herrmann, Ludovic Laugier, et al.. Dolomitic marble from Thasos at the Louvre. Open Journal of Archaeometry, PAGEpress, 2013, 1 (1), pp.14. 10.4081/arc.2013.e14. hal-02426586 HAL Id: hal-02426586 https://hal.archives-ouvertes.fr/hal-02426586 Submitted on 2 Jan 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Open Journal of Archaeometry 2013; volume 1:e14 Dolomitic marble from Thasos recognize by eye. The whiteness of Thasian dolomitic marble makes it an attractive mate- Correspondence: : John J. Herrmann Jr., Museum at the Louvre rial for sculpture, but its hardness makes it dif- of Fine Arts, 465 Huntington Avenue, Boston, MA ficult to work. On the Mohs scale, calcite is 02115, USA. Thomas Calligaro,1 Yvan Coquinot,1 rated 3, while dolomite is 3.5-4.0. Similar pure Tel./Fax: +1.617.267.9300. Maria Filomena Guerra,1 white, coarse-grained dolomitic marble suit- E-mail: [email protected] John J. Herrmann Jr.,2 Ludovic Laugier,3 able for sculpture is also found near Malaga in Key words: X-ray fluorescence, Greek and Roman 4 Annewies van den Hoek southwestern Spain and was used for sculp- sculpture, exportation. 1Research Centre of Restoration of ture at least locally in Roman times (Attanasio, French Museums, Paris, France; 2Museum 2003; Lapuente et al., 2002). Unfortunately Citation: Calligaro T, Coquinot Y, Guerra MF, analysis of stable isotopes of carbon and oxy- Herrmann Jr. JJ, Laugier L, van den Hoek A, 2013. of Fine Arts, Boston, MA, USA; Dolomitic marble from Thasos at the Louvre. In: 3 gen, the usual technique for marble prove- Department of Greek, Etruscan and th nancing, is of limited use in separating the RH Tykot (ed.) Proceedings of the 38 Roman Antiquity, Louvre Museum, Paris, International Symposium on Archaeometry – May dolomitic marbles of Malaga and Thasos since France; 4Harvard Divinity School, 10th-14th 2010, Tampa, Florida. Open Journal of their signatures overlap substantially. A recent Archaeometry 1:e14. Cambridge, MA, USA study, however, indicates that petrographic cri- teria can provide a basis for distinction Acknowledgments: the authors wish to particular- (Lapuente et al., 2002). ly thank Alain Pasquier, formerly Head of the Multimethod testing has shown that coarse- Department of Greek, Etruscan and Roman Abstract grained dolomitic marble like that of Thasos Antiquity, Louvre Museum, Paris, France. and Malaga was used for ancient sculpture th Many Greek and Roman sculptures in the Presented at the 38 International Symposium on around the Mediterranean, inland as far east th th Louvre appear to be made of coarse-grained, Archaeometry – May 10 -14 2010, Tampa, as Palmyra, and on the north shore of the Black Florida. very white dolomitic marble from the north Sea (Herrmann and Newman, 1995, 2002; This work is licensed under a Creative Commons Aegean island of Thasos, and permission was Wielgosz et al., 2002; Herrmann et al., 2002; Attribution 3.0 License (by-nc 3.0). given to test twelve of them in a non-destruc- Fischer, 2009). It is highly likely that this only tive way using a mobile X-ray fluorescence dolomitic marble comes from Thasos not ©Copyright T. Calligaro et al., 2013 (XRF) spectrometer. Coarse-grained, white Malaga. The apparent absence of Malaga mar- Licensee PAGEPress, Italy dolomitic marble sources were rare in antiqui- ble at such Spanish centers as Merida and Open Journal of Archaeometry 2013; 1:e14 doi:10.4081/arc.2013.e14 ty, and if these Thasian-looking sculptures Zaragoza (Lapuente et al., 1999, 2002) tendsuse to proved to be dolomitic rather than calcitic, it is indicate that it was only used in the immediate highly likely that they were in fact made of region of the Malaga quarries during antiquity. Thasian marble. Ten of the twelve sculptures Historical arguments reinforce this conclu- tium, a heavier element naturally substituting did prove to be dolomitic marble and therefore sion. The marble of Thasos was mentioned by calcium, were measured in two successive very probably Thasian in origin. This new ancient writers and was heavily used for sculp- runs. The magnesium and calcium X-ray lines information makes it possible to expand and ture on that island and in neighboring regions (1.25 keV and 3.69 keV) were recorded operat- enrich our knowledge of the exportation of (Grandjean, 2000), but no ancient written ing at 15 kV with a helium gas stream between marble from Thasos in both geographic and source seems to mention marble from south- the X-ray detector and the marble. The stron- chronological terms. The tests furthermore west Spain. tium X-ray line at 14.16 keV was collected at 50 confirm that dolomitic marble from Thasos The Louvre displays many ancient sculp- kV in air with a 50-µm Zn beam filter (Figure was preferred for colossal replicas of Athena of tures that appear to be marble from Thasos. In 2). XRF spectra were processed using a pro- the Velletri type and also reveal that a group of 2007 the Département des Antiquités Grecques, gram based upon the fundamental parameters imperial portraits in Algeria were carved from Etrusques et Romaines of the Louvre granted us method. Trials performed on reference marble marble blocks from Thasos. One test offered the opportunity to study twelve of them by non- samples from Thasos demonstrated the ability confirmation that a fragment in the Louvre destructive means. These pieces were chosen of the XRF system to reliably measure Mg, Ca was part of a relief in Izmir. because their provenances offered a special and Sr. Under these conditions, the magne- Non-commercialgeographical or historical interest. The objec- sium was measured at a depth of 7 µm, where- tive of our study was to tell whether the marble as the strontium was probed much more was dolomite (CaMgC2O6) or calcite (CaCO3), deeply, 1.7 and 1.1 mm in dolomitic and calcitic Introduction on the assumption that, if dolomite, they came marbles respectively (the depth at which 99% from Thasos. of X-rays escape). The strontium concentra- Marble from the adjacent zones termed tion (ranging from 20 to 120 µg/g) thus consti- Cape Vathy and the Saliari area in the north- tutes a convenient indicator of the nature of eastern part of the northern Greek island of the marble, unaffected by a possible surface Thasos is characteristically almost pure Materials and Methods alteration. In addition, the markedly different dolomite. As Attanasio has pointed out (2003), Sr/Ca ratio measured could be exploited to fin- it is the whitest commonly used ancient mar- The measurements were carried out in a gerprint Thasos marble (Figure 3). ble, and it has a maximum grain size of 1-3 fully non-destructive way using a mobile X-ray mm with a mean of slightly less than 2 mm, fluorescence (XRF) spectrometer designed at which places it among the coarse-grained mar- the C2RMF (Figure 1), built upon a 50 kV bles. Macroscopically, the stone often reveals molybdenum X-ray tube and a silicon-drift X- Results large, glittering, flaky crystals or grains, which, ray detector (12). Measurements were made together with its medium or coarse grain and on modern breaks in order to minimize the By the standards just outlined, ten of the unspotted whiteness, make it relatively easy to effects of weathering. Magnesium and stron- twelve sculptures analysed proved to be [page 68] [Open Journal of Archaeometry 2013; volume 1:e14] Technology & Provenance - Stone, Plaster, Pigments dolomitic marble (Table 1). Most of the Hamiaux, 1992), proved to have been made of syncretistic goddess Demeter-Kore-Io-Selene- dolomitic pieces had a MgCO3 component calcitic rather than dolomitic marble. This is Isis (Herrmann, 1999). The body would have between 40 and 48.6%. Two, however, had a somewhat surprising since Samothrace lies been made of limestone or some other materi- smaller MgCO3 fraction, in the neighborhood only a short distance from Thasos and even at al, a common technique in Greco-Roman of 30% (Ma1163, 4891). This discrepancy rais- this early date, the quarries of the Cape Vathy Egypt. The Louvre sculpture Ma 4891 has much es the possibility of a non-Thasian origin for area were in operation and had been used for in common with another dolomitic marble them. Their strontium components, however, relief sculpture (Grandjean, 2000). The scarci- head of a goddess in Copenhagen also attrib- were consistent with the rest of the dolomitic ty or absence of Thasian dolomitic marble on uted to Hellenistic Egypt (Herrmann and group, and at present there are no plausible Samothrace has already emerged in other Newman, 2002; Nielsen et al., 1997). dolomitic marble alternatives to Thasos. Since studies of marble work on the island The dolomitic marble sculptures in this one of the exceptional pieces probably comes (Herrmann and Newman, 1999; Maniatis et al., series of tests document in various ways the from Egypt (Ma4891), it is particularly unlike- 2012). Together, these findings make it clear diffusion of Thasian sculptural marble ly that its marble came from an obscure quarry that proximity and economic convenience throughout the vast territories of the Rome in Western Spain.