PROVENANCE OF MEDIEVAL PIETRA OLLARE ARTEFACTS FOUND IN ARCHAEOLOGICAL SITES OF CENTRAL–EASTERN ITALY: INSIGHTS INTO THE ALPINE SOAPSTONE TRADE*

Medieval archaeological findings made of pietra ollare (basic and ultrabasic metamorphic rocks belonging to the greenschist facies) and coming from central–eastern Italy have been characterized through a petrological study (modal mineralogy, whole‐rock geochemistry, XRD and SEM–EDS analyses). The pietra ollare artefacts considered in this work consist of fine‐grained, grey to pale‐grey, magnesite‐bearing talc‐schists (i.e., soapstones). In order to determine their production centres, Alpine soapstones quarried in ancient times were selected on the basis of their mineralogical and textural compatibility with the archaeological findings. The mineralogy and chemistry (major and trace elements) contributed to establishing the ancient quarries of the Valchiavenna (central Alps) as the probable provenance area. This archaeometric investigation proves that Alpine artefacts made of pietra ollare spread to the south of the Po Plain during the Middle Ages. It can be inferred that the Alpine soapstone trade towards the Marche and Abruzzo regions was addressed through the main waterways: Lake Como, the Adda and Po Rivers and finally the Adriatic Sea.     

THE FIRST ARCHAEOMETRIC CHARACTERIZATION OF ROMAN MILLSTONES FOUND IN THE AQUILEIA ARCHAEOLOGICAL SITE (UDINE,ITALY)*

An archaeometric study of all the Roman millstones preserved today in the National Archaeological Museum of Aquileia, the ancient capital of the X Regio Augustea –‘Venetia et Histria’ located on the Friuli plain (northeastern Italy), has been recently envisaged to define their geological–geographical provenance. We present here the results of the first step of the research, which is aimed at characterizing all of the definitely allochthonous lithologies. In order to carry out petrography on thin‐section and geochemical analyses, 10 small samples were picked out directly from Pompeian‐style millstones (catilli and/or metae) and rotary querns. Five different lithologies originating in various Italian regions were recognized: eight samples consist of pale‐ and dark‐grey lavas from the Venetian Volcanic Province, Vulsini Volcanic District (Latium), Etna Volcano and Pantelleria island (Sicily), whereas two samples were shown to be made of green garnet‐bearing schists (pietra ollare) from the Western Italian Alps. The presence of Alpine pietra ollare in northeastern Italy, used to produce pots and food containers, was established for numerous classical findings at Roman and Middle Age sites, but the analysed items represent the first evidence for the utilization of this kind of stone to produce mills during the Roman epoch.