Archaeometric study of the hopper-rubber and rotary Morgantina-type volcanic millstones of the Greek and Roman periods found in the Aeolian archipelago (southern Italy)

A comprehensive investigation and classification of volcanic millstones of the Greek and Roman periods found on three islands of the Aeolian archipelago (Lipari, Salina and Filicudi) has been reported. Most of the analysed hopper-rubber (Olynthian-type) and rotary (Morgantina-type) millstones are made up by basaltic andesite and andesite lavas belonging to the medium-K and high-K calc-alkaline series. Among the andesite group we also identified one millstone made of a cordierite-bearing andesite lava. In addition, three latites (shoshonitic series), two hawaiites (Na-alkaline series) and one tholeiitic/transitional basaltic andesite have been found. Modal mineralogy, petrography and major and trace element chemistry of the millstones are consistent with a provenance from the Aeolian archipelago and Sicily. The Aegean colonization of the Aeolian archipelago led to the manufacture of the hopper-rubber millstones through the local exploitation of Lipari lavas, whereas the rotary Morgantina-type mills represent quarrying sites of Lipari itself, Vulcano Island and Sicily (Etna and the Iblean Mountains). An intrusive, two-mica granodiorite rotating hand mill has also been identified among the archaeological artefacts under study, and a possible provenance from Capo Vaticano (Calabria) has been argued. The localization of the sites of quarrying and provenance of the artefacts highlights that the rotary millstone trade in southern Italy should have begun from the third century BCE, which is the period to which the Morgantina-type mills have been dated.