Texture and function. The multiple uses of Greywacke among northwest Iberian prehistoric groups
Channel: Recording Archaeology
Date: 2016-12-20

It is a known fact that the available lithic resources in inland Portugal are quite distinct from the ones in coastal Mesozoic sedimentary basins. This is reflected in lithic assemblages where quartz is clearly dominant while exogenous rocks such as flints and cherts are residual and have specific roles in the raw material economy. Work undertaken recently in the Sabor valley, northeast Portugal, brought to light several prehistoric assemblages (from Palaeolithic to Bronze Age) where a huge range of local and regional rocks were exploited. Dozens of different raw materials were identified and such diversity led to the creation of a regional raw materials reference collection, now in the Natural History and Science Museum of the University of Porto. Although several varieties of quartz dominate the assemblages, other local high silica content rocks were selected by prehistoric communities such as hydrothermal silicifications, opal, jaspers, lydite, rhyolite, mafic granulite, and greywacke among others. These had a crucial role in the economy of those human groups. Among all lithologies greywacke represents an important part since it was applied in several uses throughout times. It presents not only decent knapping aptitude but also a good thermal conductivity. With easy access it was used not only on dwelling structures (hearths, post holes, floors), portable art (engraved slabs), anvils, but also on knapped stone assemblages as blanks or tools. It was also applied in daily tasks. In this paper will be presented the multiple uses of greywacke from Palaeolithic to Bronze Age, in a specific region and its significance for each human group.

Author - Gaspar, Rita, Porto, Portugal (Presenting author);
Co-author - Ferreira, João, Porto, Portugal