The Sauveterrian Chert Assemblage of Galgenbühel Dos de la Forca (Adige Valley, South Tyrol, Italy) Procurement Areas, Reduction Sequences, Tool Making

Raw-material analysis combined with a techno-typological study was carried out on the lithic assemblages stemming from the Sauveterrian site Galgenbühel/Dos de la Forca. The aim was to gain a better insight into the management of raw material, reduction sequences (chaînes opératoires) and human mobility in the context of the Early Mesolithic frequentation of the Adige Basin. The Galgenbühel/Dos de la Forca rock-shelter is located in Salurn (Adige Valley, Northern Italy), in the province of Bolzano/Bozen. The site lies on a debris cone at the foot of a Triassic wall and overlooks the valley bottom. Radiocarbon dates attest to repeated human frequentation between 9265 ± 70 BP (ETH-27173, 8425 – 8089 cal. BC) and 8560 ± 65 BP (ETH-22091, 7705 – 7478 cal. BC). The economy of the site was related to the resources of the valley bottom wetland and the forested surroundings. The exploitation of aquatic fauna, mainly represented by fish, freshwater molluscs and beavers, ungulates (mostly wild boar and red deer) and small carnivores (dominated by wild cat) is documented. The present study regards the lithic assemblages of phases 2, 3 and 4. Raw-material analyses, conducted on a sample of about 1,300 artefacts, provide evidence for the exploitation of Upper Jurassic to Eocene cherty limestones that were deposited on the western margin of the Trento Plateau, namely the Maiolica, Scaglia Variegata Alpina, Scaglia Rossa and Chiusole formations. On the basis of the depositional patterns of the area that influenced the qualitative and quantitative distribution of the cherts, two procurement areas were identified: the outcrops of the Non Valley, 10 km in a straight line to the west of the site, and those located in the area of Mount Finonchio and the Folgaria Plateau, at a straight-line distance of approximately 35 – 40 km southwards. Non Valley cherts were collected predominantly from detritic covers, whilst Finonchio/Folgaria raw material was collected mainly from the residual soils of the karstic plateau. Despite the different distances from the site, the frequency of Non versus Finonchio/Folgaria cherts does not present a relevant difference. The relatively high number of the latter cannot be explained by the better quality of raw material, as the varieties of chert from both areas, being all very fine crystalline cherts, are similar. Indeed, no significant differences were observed as regards the size and shape of the exploited blocks, reduction processes, blank selection and tool manufacturing. Rough chert blocks from both areas, of 6 – 8 cm maximum side length, were transported to the site to be worked. Natural diaclases were generally used as striking platforms and core flanks. The lithic production aimed to produce small series of thin and non standardised bladelets. Three different reduction sequences have been identified: on prismatic volumes, on oval flat surfaces (namely thick flakes with facial exploitation) and on narrow surfaces. Knapping was unipolar. Maintenance was carried out through lateral flakes or thick detachments to eliminate hinged negatives. Thin blanks, mostly bladelets, were transformed into armatures. These are mostly represented by triangles and backed points. Transformation occurred by means of intentional shortening using the microburin technique and by unipolar abrupt retouch. Common tools were obtained from all the different blank categories (mostly on generic flakes), including by-products stemming from initialisation and maintenance. All stages of the production process are represented, attesting that flaking occurred on site. Only a modest number of large specimens are incompatible with the described bladelet reduction sequences, suggesting the importation of finished items, which, at least for phase 2, are more frequently made on Finonchio/Folgaria raw material. A picture emerges of a rather indistinct raw-material procurement carried out in two different areas located at some distance from each other. The same knapping goals were met, suggesting the collection of raw material during periodic migrations possibly on the occasion of other economic activities, such as the exploitation of several ecological niches in a wider area. This supply strategy persisted over a time span of several hundreds of years, revealing a continuity in the habits of hunter-gatherer groups belonging to the same cultural tradition. As regards the accessibility of the identified areas, the outcrops in the Non Valley and in the Finonchio/Folgaria area are located in a mid-mountain territory and are easily accessible from the Adige Valley. Evidence of collection from torrent pebbles during phase 4 could indicate chert collection along the Noce River. A direct conjunction between the Folgaria Plateau and the Galgenbühel runs along the Adige Valley. Because of the complex hydrographic setting of the valley bottom supposed in the Early Holocene, with a meandering river course and secondary standing waters, the routes along the valley would have possibly crossed the detritic talus and alluvial cones. Furthermore, the use of water ways has to be taken into account as we are referring to human groups with a wetland-based economy.