Ceramic ecology in the Holocene Central Sahara. Archaeometric data from the Acacus Mts. (SW Libya).

The paper aims to discuss the archaeometric characterization of 69 potsherds, from a rock shelter located along wadi Takarkori, and 26 sediments sampled along the Wadi Tanezzuft and the Wadi Takarkori itself. The site contains a rich archaeological record spanning five millennia (from around 8900 to 4200 uncal. years BP) from Late Acacus hunter-gatherers to Late Pastoral herders. The purpose of the analytical project is to study the technological changes in the chaîne opératoire of pottery production, from raw material procurement to the finished product, which deals with the ecology of ceramic production in Tadrart Acacus and with the comparison with other archaeometric researches carried out in the area. Geologically, this region is composed of Palaeozoic sedimentary rocks (sandstone and shale) while the intrusive formation of the Tassili massif outcrops at ca. 50 Km south-westward the site. Petrological (MO, SEM/EDS), mineralogical (XRPD) and chemical (XRF) data distinguished three main fabrics (Q, QC and QF) with different prevailing clastic constituents. The Q and QC fabrics present a common petrofacies. Fabric Q is characterized by monocrystalline quartz and rare polycrystalline quartz. Elongated vegetal inclusions are common in fabric Q. In fabric QC both polycrystalline quartz and vegetal inclusions are less frequent than in fabric Q and calcareous aggregates, cementing iron oxides and quartz grains, are present. Both fabrics mirror the Paleozoic quartzarenitic substrate of the Tadrart Acacus Mountains. The raw materials may results from a common fluviatile sediment, with a greater or smaller aeolian component, and can be interpreted in terms of sedimentary facies in a wadi/swamp transition environment. The calcareous aggregates of fabric QC comes from calcareous mud, whose authigenic precipitation in former closed lakes and ponds, found in sub-tropical region is widely attested. The QF fabric is characterised by angular or sub-angular grains of quartz, potassium and plagioclase feldspars, along with biotite and hornblende. QF fabric suggests the circulation of pottery from areas closer to the intrusive formation of Tassili Massif. The archaeometric results will be discussed with reference to regional environmental changes, local cultural dynamics, settlement systems, and mobility strategies.