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This paper presents for the first time chemical data on the ancient (Antiquity period) marble quarries of Delos Island and some architectural marbles from its famous and exceptionally well-preserved archaeological site. Delos geological substratum is mostly composed of granite, including very few decametric marble enclaves. However, ancient Delian architecture is dominated by gneiss and marbles. A large quantity of marble had thus to be imported from neighbouring Cycladic Islands and continental Greece. Their provenances remain mostly unknown. Several analytical methods have been developed in archaeometry for years to determine the origin of marbles, but they are generally destructive. This paper reports a methodology based on a hand-held portable X-ray fluorescence (pXRF) analyser to detect major and trace elements often used in provenance studies. Drawbacks of using those elements for marble provenance and analytical limitations attached to portable instruments were frequently discussed. Here the usefulness of pXRF for marble provenance research was tested in association with principal component analysis (PCA). Two artefacts of presumed Delian origin were selected and the results showed that one of them came undoubtedly from a Delian quarry while the other one was not of local origin. This protocol appeared to be a powerful tool when conventional destructive analyses are precluded.

Traces of extraction in Delian marble quarries attest their exploitation during Antiquity. A preliminary non-destructive provenance study confirmed the presence of indigenous marble in Delos constructions. In contrast, Delos marble quarries have not been geochemically described so far. Therefore, a detailed (1/5000 scale) geological mapping and cross-sections were performed in the four Delian marble quarries in order to better determine their dimension and to estimate the volume of extracted marble. The surface of the quarries was revised into up to six times larger areas, increasing the extracted volume estimations. Quarries were sampled and studied with mineralo-petrographic (optical and electronic microscopy, X-Ray Diffraction) and isotopic (δ13C and δ18O) characterization. Three categories were observed, i.e., a coarse whitish to bluish marble, a fine yellowish dolomitic marble and marble with giant white and blue calcite crystals. The Maximum Grain Size associated with oxygen and carbon isotopic ratios showed a good potential to distinguish Delian marbles from most of the main Mediterranean marbles used during Antiquity. However, geochemical elemental analyses such as trace elements analysis could supplement Delian marble characterization which will benefit future provenance studies.

Établissements porteurs de l'opération : École française d'Athènes 1 L'exploration géo-archéologique de Delphes et de ses environs s'est poursuivie du 15 au 28 mai 2021 et du 25 au 29 octobre 2021 dans le cadre du programme quinquennal de l'EFA « La pierre à Délos et à Delphes ». Les lithologies de l'élévation des monuments ont été vérifiées dans les parkings à blocs du sanctuaire d'Apollon et de ses abords, du gymnase et du sanctuaire d'Athéna Pronaia, permettant la mise en évidence de l'emploi de deux nouveaux faciès de grès, communément appelé « pôros » dans la littérature archéologique (1). Une analyse de la collection lithologique de Delphes conservée à La pierre à Delphes : matériaux et carrières (2021) Bulletin archéologique des Écoles françaises à l'étranger , Grèce La pierre à Delphes : matériaux et carrières (2021) Bulletin archéologique des Écoles françaises à l'étranger , Grèce

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