Cal Sitjo: A new Mesolithic to Neolithic sequence in a chert-rich region (Sant Martí de Tous, NE Iberia)

Cal Sitjo is a new archaeological sequence located in a chert-rich region of the NE Iberian Peninsula, in the town of Sant Martí de Tous (Anoia, Barcelona). The area has undergone significant anthropisation and several archaeological sites (e.g., Vilars de Tous), quarries and workshops for the exploitation of chert (e.g., La Guinardera) have been documented, corresponding to different periods. The abundance of chert made this region an almost obligatory passageway for hunter-gatherer communities such as those occupying the nearby cliffs of Cinglera del Capelló (Capellades), located at a direct distance of 15 km, as well as an ideal settlement for later farming communities. Discovered in 2019, the first excavation campaign was carried out in the fall of 2020. Dates have been obtained from a known sequence of around 8 m, providing a chronological framework that ranges from the Mesolithic to the Middle Neolithic. The preliminary results of this excavation have brought to light lithics, ceramics and charcoals from the Neolithic levels (Levels 3 and 4), and faunal, lithic and charcoal remains from the Mesolithic levels (cleaning section). Our preliminary results confirm that this sequence is an ideal location for a diachronic study of the evolution from the last hunter-gatherers to the first farmers, from a paleoenvironmental and technological perspective, as well as in terms of chert management and distribution in a territory with a great abundance of this raw material

The Guinardera quarry (Sant Martí de Tous, Barcelona): A new chert exploitation location during historical times

In 2014, an anthropic accumulation of chert material was discovered in La Guinardera area, at the southwest of the Sant Martí de Tous town (Barcelona, NE Iberian Peninsula). In 2018 a first archaeological intervention was carried out in two locations: La Guinardera and La Guinardera Nord. After the fieldworks, these two accumulations were interpreted as chert workshops. These workshops are in the St. Genís Formation, included within La Noguera lacustrine system and dated to the Priabonian age (upper Eocene). The St. Martí de Tous area presents shallow lacustrine conditions typical of sabkha environments, in which layers of gypsums and sandy lutites are interspersed with tabular red sandstone levels, yielding different varieties of chert. The Guinardera chert is characterized by a fairly homogeneous matrix, presenting a fine texture, with a microcrystalline and spherulitic length-slow chalcedony matrix, and a combination of grey colours, in general of dark hues, with an opaque diaphaneity but translucent at the edges. The archaeological assemblage from La Guinardera Nord site allows us to identify a chert workshop for the production of gunflints. The heterogeneity of the assemblage at La Guinardera site precludes assigning it to any single chrono-cultural period or function. The technological characterization of La Guinardera Nord site reveals distinctive attributes of a gunflint workshop that can be differentiated from prehistoric workshops. The presence of square and thick preforms, oxide traces on butts and ventral faces, marked bulbs and thick platforms, together with fresh edges on flakes and blades and the near-absence of patinated materials, corroborate it. The presence of these two deposits within the above-mentioned formation shows us a repeated landscape exploitation pattern for raw material extraction, since references chert use range from the Middle Palaeolithic (e.g., Abric Romaní) to historical times (e.g., La Guinardera Nord)