Melting, bathing and melting again. Urban transformation processes of the Roman city of Munigua: the public thermae

Although microarchaeological techniques are being increasingly applied to European urban contexts, its integration in classical archaeology projects is far from systematic. In this sense, the archaeological record of Roman cities—because of their vitality, diversity and continuity of occupation—are excellent arenas to develop the direction of these techniques. Here, we show the results of a geoarchaeological study of the chronostratigraphic sequence of the public thermae of the Roman city of Munigua (Sevilla, Spain). Soil micromorphology, along with physico-chemical and geochemical analyses, have revealed dynamics of urban change marked by an initial use of space dedicated to metallurgical production and a later course of urban planning, construction of a thermae complex and the life cycle of this public building. The integrity of the archaeological record has allowed for the use of new descriptive criteria for observing metallurgical by-products of lead and iron melting in thin section and for offering new contextual information about production, technology and site formation processes. X-ray fluorescence (pXRF) enabled the characterization of geochemical anthropogenic inputs related to metallurgical processes. Physico-chemical and chemical analysis have provided significant data about diachronic use of the space that has permitted us to assess abandonment and a later reuse of this public building for metal recycling activities during Late Antiquity. This study reaffirms that the combined use of micromorphology, physico-chemical analyses and geochemistry in Classical Archaeology, are powerful tools in order to decipher urban transformation processes, most of them not visible in the macroscopic record. Understanding the scope of these practises is essential in order to assess the transformation in morphology and topography of urban sites, especially during Late Antiquity.