Old recipes, new strategies: Paleoenvironment, georesources, building materials, and trade networks in Roman Tuscany (Italy)

The Grosseto plain has undergone extensive morphological changes. The shoreline progression has been taking place during the last millennium and has deeply affected settlement, infrastructural, and socioeconomic dynamics. Consequently, this study aims to (a) localize the raw materials exploited during the Roman period for building materials production, (b) reconstruct the production technology, and (c) provide a meaningful reconstruction of the commercial dynamics between local "municipal" productions and "urban" imports. The chemical, mineralogical, and petrographic investigations performed on 34 stamped bricks from the Roman territories of Vetulonia, Rusellae, Heba (Aia Nova), and Saturnia supported the following major achievements: (a) Most of the Rusellan producers used the continental deposits outcropping along the Ombrone River while a few of them exploited the coastal or marine deposits. Aia Nova and Saturnia producers used the Zanclean marine deposits. (b) Brick-making technology involved very little or no preparation of the paste and firing temperatures ranging between 650 degrees C and 900 degrees C. Calcite temper was found in Rusellan bricks while decantation was hypothesized for Saturnia bricks only. (c) Commercial dynamics changed abruptly after the the mid 1st century AD when local productions, run by local aristocracies, started declining in favor of urban imports, until being completely supplanted during the Trajan age.