A Late Iron Age hillfort under the magnifying glass. Microarchaeological research at Icedo fortified site (Burgos, Spain)

Abstract This study focuses on domestic architecture from the Early-Late Iron Age (5th to first centuries BCE) at the hillfort of Icedo, which is located in the Las Loras Geopark in Burgos, Spain. The most up-to-date methodological approaches to macro and micro analysis are used to explore the topic. In other words, it examines the architectural, social and ecological characteristics of the so-called Late Iron Age oppida. This approach aims to shed light on mountain occupation and resource acquisition during the late 1st millennium BCE. Microcontextual geoarchaeological methods were employed to analyse the domestic architecture of the site, which consists mainly of a circular hut built with a limestone base, clay, lime and vegetal materials. These methods included micromorphology, in addition to integrated phytolith, calcitic microfossil and charcoal analysis. Previous stratigraphic excavations revealed well-preserved construction remains, such as wooden frameworks covered with lime and clay plasters. The paper's results emphasise the use of agricultural by-products, notably cereal straw, as stabilisers in earthern building materials. Radiocarbon dating indicates that the hillfort was constructed between 515 and 385 cal BCE, which correlates with neighbouring Late Iron Age sites, such as the La Ulaña oppidum . Further analyses of charcoal, phytoliths, and calcitic microremains suggest a reliance on local plant resources and an advanced understanding of the selection and preparation of materials. Integrating macro- and microarchaeological evidence, such as charcoal, pottery, bone, pollen, phytoliths, and geomorphology, has provided insights into the socio-economic practices of the inhabitants and their adaptation to the mountainous landscape. This interdisciplinary approach improves our understanding of the domestic and spatial organisation of protohistoric settlements and their cultural significance in the Cantabrian Mountains. The case-study contributes to broader discussions on societal resilience and the interactions between indigenous communities and their environments during the Late Iron Age.