Querns and mills during Roman times at the northern frontier of the Roman Empire (Belgium, northern France, southern Netherlands, western Germany) : unravelling geological and geographical provenances, a multidisciplinary research project

This paper presents the results of a multi-disciplinary provenance study of querns and millstones during the Roman period (1st-4th century CE) in the northern part of the Roman Empire (provinces of Gallia Belgica and Germania Inferior). Comparative petrographical, mineralogical and geochemical analysis allowed an international team of archaeologists and geologists to identify the different raw materials used for the manufacturing of querns and millstones. As a result, lithostratigraphic assignments as well as geological-geographical provenances are suggested or corroborated for the broad spectrum of these natural geo-materials. We give evidence for the exploitation of at least seven different rock types. They include sedimentary rocks (fine- to coarse-grained quartzitic and arkosic sandstones, conglomerates, limestones) and volcanic rocks (vesicular lavas) derived from different geological strata in the following geological-geographical settings: the volcanic Eifel area (Pleistocene lava), the Ardennes Massif (Palaeozoic sedimentary rocks) and the Paris and Northern Sea Basin (Cenozoic sedimentary rocks). Furthermore we show that a large diversity existed within different productions (different types of hand-mills and mechanical powered mills) and distribution patterns. This paper provides new data which will lead to fresh insights into the socio-economics of the local “Gallo-Roman” communities and into their networks within the northern Roman Empire.