Micromorphology of the Early Iron Age semi-cemented floors: El Calvari del Molar (Tarragona, NE Spain) as case study

This paper presents the microstratigraphic analysis of the protohistoric site El Calvari del Molar, dated to the 8th century and the first quarter of 6th century BCE. It focuses specifically on Room 8, located in the northern part. The sedimentary record covers different stratigraphic units, including several floors with their layers of preparation and domestic structures. The study of these floors, mainly through micromorphology, allows us to determine the composition, the processing and the technical treatment as well as the possible origin of the lithological materials used in their manufacture. We highlight that the floors are composed of earth construction, made of local carbonated materials, mainly clayey fine sands. Mixing this material with water would cause a precipitation of CaCO favoured by the impermeability of their preparation layers, mostly silty clay aggregates, leading to the semi-cementation of the floor, which appears to have been the aim of the builders of El Calvari. This type of earth floor brings together a series of characteristics at the construction level such as cohesion among particles and tenacity, similar features to lime mortars. In short, we have the opinion that the micromorphological analysis is an essential tool for the study and interpretation of domestic architectural elements. In this case, it has allowed us to identify and characterize the techniques and construction strategies of this type of floor by these first protohistoric builders of the NE Iberia.This paper is part of the HUM2004-04861-C03-01 and HUM2007-65725-C03 research projects funded by the Ministry of Science and Innovation and the HAR2010-1105-C02 research project funded by the Ministry of Economy and Competitiveness. The research has also been funded by the grants awarded to the “El jaciment protohistòric del Calvari del Molar i l'àrea minerometal·lúrgica Molar-Bellmunt-Falset” research programme by the Culture Department of the Regional Government of Catalonia, the Tarragona Provincial Government and the Municipality of El Molar (in order to carry out the excavation of the El Calvari archaeological site)