The volcanic millstones from the archaeological site of Morgantina (Sicily): provenance and evolution of the milling techniques in the Mediterranean area*

The Morgantina archaeological area, inhabited from the Early Bronze Age, had its widest expansion from the fifth to the first century bc . The volcanic millstones found at Morgantina fall into three different groups on the basis of the milling technique: (i) saddle querns (known from the Middle–Late Bronze Age and Iron Age); (ii) rectangular hopper‐rubbers (Olynthian) millstones, the invention of which dates to the fifth century bc ; and finally (iii) Morgantina‐type rotary millstones (starting to be used from the fourth to the third century bc ). In order to determine the provenance of the raw materials (lavas) used for all these millstone types, we collected 38 very small rock samples for thin‐section modal mineralogy, petrography and major trace element composition. The results have contributed to classifying different lithotypes and distinguishing between provenance from Etna and the Hyblean Mountains, the two volcanic areas respectively north‐east and south‐east of Morgantina. Saddle querns are made of tholeiitic basaltic andesites from the Hyblean Mountains and transitional basalts, mugearites and hawaiites from Etna. The variety of sources of portable saddle querns, mostly used in households, indicate that there was no general preference for specific quarrying sites. By contrast, the rectangular hopper‐rubber and the Morgantina‐type millstones, which document the period of Morgantina's greatest prosperity, are almost completely made of hawaiites from Etna. The use of a specific lithotype (i.e., Etna hawaiite) for the more efficient rectangular hopper‐rubber and rotary millstones could be linked to the fact that these mills may have been operated in business establishments. It is worth noting that the Gornalunga river was, in antiquity, a waterway joining Morgantina to the final stretch of the Simeto river and then the Ionian coast. The best candidate areas for the millstone hawaiite quarrying sites from Etna are the far south‐western sectors of the volcano, along the Simeto Valley (i.e., the ‘Piano Provenzana’ Formation) or the inner suburb of present‐day Catania (i.e., the ‘Pietracannone’ Formation). The very efficient Morgantina‐type rotary millstones spread during the reign of Hieron II of Syracuse (275–215 bc ) in eastern Sicily and met the need for grinding large quantities of cereals during a relatively peaceful time and a period of agricultural development.     

Contribution of strontium to the human diet from querns and millstones: an experiment in digestive strontium isotope uptake

The question of whether rock grit ingested unintentionally from querns, metates or millstones, or deliberately through pica or geophagy, is bioaccessible in the human gut has not been addressed in archaeological strontium (Sr) isotope studies. This study employed the unified bioaccessibility method and determined that ingested rock grit can provide bioaccessible ⁸⁷Sr/⁸⁶Sr, but that unintentional consumption is unlikely to constitute > 1% of the diet (by mass) and will not significantly change, that is, by > 0.001, human skeletal ⁸⁷Sr/⁸⁶Sr. The use of locally or non‐locally sourced querns or millstones will not affect the interpretation of archaeological human ⁸⁷Sr/⁸⁶Sr values in Britain.     

Archaeometric Study of Volcanic Lithic Objects from The Longola (Poggiomarino) Protohistoric Site,Southern Italy: Regional Versus Extra‐Regional Provenance

The Longola protohistoric village (spanning from the late Middle Bronze Age to the sixth century bc ) is a perifluvial settlement located in the Sarno River floodplain to the north‐east of Pompeii (southern Italy) and east of the Somma‐Vesuvius volcano. A great abundance of artefacts have been found at Longola and in the neighbouring areas, including a variety of volcanic stone objects, mainly related to building and to the manufacture of ordinary tools and instruments. The aim of our work is to characterize lithic objects (lava pebbles and millstones) and to understand their geological provenance by petrographic and geochemical studies. Compositions of millstone samples (porphyritic phonolitic tephrites) and of a set of pebbles (mainly phonolitic tephrites, leucite–shoshonites and trachytes) are compatible with the Somma‐Vesuvius magmas erupted before 8 ka bp . For the trachyte lithics, an additional source from the Accademia lava dome (Phlegrean Fields) cannot be ruled out. Among the pebble samples, a rhyolite and a poorly evolved trachyte clearly lie outside the compositional variation of the Somma‐Vesuvius and other volcanoes of the Naples area (e.g., Ischia and the Phlegrean Fields) and emphasize an extra‐regional provenance. Ponza Island is the best candidate for the provenance of the above two outlier samples.     

Mediterranean trade of the most widespread Roman volcanic millstones from Italy and petrochemical markers of their raw materials

The petrochemical study of millstones can contribute to improve the archaeological research into reconstruction of ancient communication routes and trade networks. Volcanic rocks are geographically restricted and rather rare in the Mediterranean regions, and during the Roman period Italian volcanoes were important sources of raw materials for millstones, so the task of determining their geological origin is relatively straightforward. The Italian vesicular volcanics most frequently employed for this purpose were: trachytes from Euganean Hills (Veneto), leucite-bearing lavas from the Vulsini Volcanic District (Latium), basic-intermediate leucite-bearing lavas from Somma-Vesuvius (Campania), silica undersaturated lavas from Monte Vulture Volcano (Basilicata), a rhyolitic ignimbrite from Sardinia and basic products from Mount Etna and the island of Pantelleria (Sicily). This paper contains a general outline of the trade network for each volcanic typology used for millstones during the Roman period – updated with data concerning the leucite-bearing lavic items discovered in the archaeological sites of the ancient Cuicul (now Djemila, Algeria) – together with a summary of their petrographic and geochemical features.