Rozpoznanie petrograficzne i analiza geoarcheologiczna kamiennych zabytków ruchomych z cmentarzyska w Świbiu / Petrographic identification and geoarchaeological analysis of lithic portable artefacts from the cemetery at Świbie

Rozpoznanie petrograficzne i analiza geoarcheologiczna kamiennych zabytków ruchomych z cmentarzyska w Świbiu / Petrographic identification and geoarchaeological analysis of lithic portable artefacts from the cemetery at Świbie

The site of Świbie 16 is located near the border of two very important physiographic units: the Silesia Upland Macroregion and the Silesia Lowland Macroregion (Kondracki 2002; Solon et al. 2018; Richling et al. 2021). Such a location offered good access to the rocks abundant in the former macroregion and the rivers and arable lands in the latter. Geologically, the discussed site lies within the Krakow-Częstochowa monocline. The identification of raw materials was carried out using macroscopic methods only, using Brinell magnifiers with 10x and 20x magnification, hydrochloric acid (HCl 5%), and the Munsell scale.

Middle Triassic rocks occur in the direct subsoil of the Świbie 16 site. They occur as Muschelkalk (Lower Gogolin Beds) and limestones and marls (Upper Gogolin Beds). Small quarries of these rocks operated within a radius of 10 km from the site. Within a radius of 15-20 km from Świbie 16, outcrops of other rocks can also be found: Lower Carboniferous beds (Visean; in the form of greywacke sandstones, shales and mudstones), Lower Triassic (Induan-Olenekian; sands, motley (red) sandstones, clays, claystones and mudstones), Middle Triassic (Anisian, the so-called Jemielnica Beds, formed as dolomites), Upper Triassic (Keuper (=Carnian-Norian)), the Lisowskie beds (occurring, among others, as laminated, motley claystones of various colors, including yellow-aquamarine and green), and Lower Jurassic. Younger sediments are represented by glacial, fluvioglacial and fluvial sediments (clays, sands, gravels and even boulders). These formations contain both pebbles of the bedrock and Scandinavian rocks. In the immediate vicinity there are also sites of alluvium, lake silts with chalk, and peats, which are the remains of a Holocene water reservoir.

The origin of the Muschelkalk objects found in graves 275 and 286 is least in doubt. However, their interpretation as artefacts should be approached with caution, because no obvious traces of processing were noticed during their examination. Four items (an axe, a polisher, a whetstone, and a geofact) were made from sandstone. In all of them, the raw material is very similar petrographically, and its source should be sought in the Lower Triassic rocks or fluvial gravels occurring south of Świbie. In grave 16, an axe made of amphibolite was found. This rock probably comes from fluvioglacial deposits. Two objects (an axe and a disc with a hole) were made of greenish shales. Similar shales and claystones come from the Lisowskie beds, which occur not far north of the site. The three quartz pebbles analysed are typical, natural components of Quaternary fluvial or fluvioglacial gravels and are not particularly interesting for geoarchaeological analyses.
The presented geographical, geological and lithological context, in confrontation with the results of the macroscopic petrographic analysis of lithic artefacts from the Świbie 16 site, allows us to conclude that the raw materials used for their production are of local provenance. They most likely come from a distance of no more than 10–15 km from the site.