Iron Age ovens and hearths from the hilltop of Quinta de Crestelos, Sabor Valley (NE Portugal): An archaeobotanical approach on typology, functionality and firewood use

Abstract

The construction of Baixo Sabor Dam (NE Portugal), led to the discovery and excavation of the site of Quinta de Crestelos, with a human occupation ranging from the Early Palaeolithic to mid-20th century. Its Iron Age phase, found at the site's hilltop, revealed an unprecedented large number of combustion structures, comprehending several typologies of ovens and hearths, as well as refuse deposits in which archaeobotanical samples were recovered. Given the number and interpretative importance of these structures to the general understanding of the site, a holistic approach to their study was devised. This research combines the analysis of archaeobotanical samples with the morphological study of archaeological features comprising typological analysis. Such corpus of data is finally compared with ethnographical examples. The objectives of this study were to identify the main firewood species used inside the ovens, to define patterns of fuel use, to evaluate the existence of firewood selection - including both taxonomic outcomes and dendrological attributes - and their possible determining factors, as well as these structures functional purposes and patterns of use. The analysis of the carbonized plant content in these combustion structures displayed a diverse range of 15 taxa, with the majority of the ovens and hearths revealing predominance of Arbutus unedo, Cistus sp., Fraxinus sp., Juniperus sp. or Quercus evergreen. Triticum aestivum/durum is the main crop recovered in the studied samples, followed by Panicum miliaceum. Residual presences of Hordeum vulgare, Vicia faba, Vitis vinifera and Papaver sp. were recovered as well. The archaeobotanical results, together with the typology of the ovens and hearths, their spatial distribution and ethnographical examples, allowed the discussion of the structure's functionality, the identification of patterns and trends of their use according to different typologies and contexts and the recognition of possible firewood selection and storage practices. This study also provides a preliminary approach to the paleolandscape of the site during the Iron Age of NW Iberia.