The Panadella chert (Montmaneu Formation): a high-quality raw material in the Abric Romani sequence (NE Iberian Peninsula)

The Montmaneu Formation is located at the NE margin of the Ebro Basin (Catalonia, Spain), and is dated to the Rupelian (Lower Oligocene). It is formed by 120 m of light grey stratified limestones with bedded-nodular chert, the Panadella chert, associated with the La Segarra lacustrine system. This chert is macroscopically characterized by very fine-grained, homogeneous, opaque greenish black colors, containing bioclasts that generate mudstone-wackestone textures. Thin-sections show a micro-cryptocrystalline quartz matrix with micritic calcite, abundant charophytes, and scattered detrital quartz. These features confer excellent qualities for knapping, as attested by its suitability for manufacturing stone-tools throughout the Abric Romani sequence (Capellades, Barcelona). The Abric Romani rock shelter has approximately 50 m of sedimentary infilling ranging from 110 to 40 ka BP. The archaeological assemblages recovered in several levels from 50 to 55 ka BP present this chert as lithic manuports. The Panadella lithotype is scarcely exploited in most of the levels, although differential management strategies are observed. At an intra-assemblage level, there are no differences in the technical strategies for the exploitation of the Panadella chert when compared with other chert lithotypes. Diachronically, however, the Abric Romani sequence shows a tendency of the Panadella chert to increase when complex reduction methods based on predetermination (e.g., Levallois) are dominant. As we have demonstrated by means of geoarcheological surveys, the Panadella chert was procured in primary formations, confirming the increase in the procurement radius of the Neanderthals who occupied the Abric Romani site to about 24 km.