Interpretation of lithic remains in fluvial terrace contexts: an example from Central Portugal

Abstract

Interpretation of lithic remains in fluvial terrace contexts : an example from Central Portugal. Archaeological remains, mainly lithic artefacts, are recovered in quaternary fluvial deposits all around the world. Fluvial systems are dynamic and diversified ; the same goes for their deposits, thus differentially affecting the implements found. The deposits, coexisting at the same time, are correlated to different lithologies, from the coarsest of the channel fillings (pebbles, gravels and sands) to the finest of the floodplain sediments (silts). During a fluvial sedimentary cycle, water energy can change, with repercussion on deposit formation, position of lithic remains and their physical alteration. In order to define a taphonomy of archaeological remains, the geoarchaeological understanding of these implements has to be based on an accurate characterization of the deposits along with a detailed record of artefact orientation and observation of physical alteration. We aim to discuss these issues by referring to the Middle and Late Pleistocene archaeological site of Ribeira da Ponte da Pedra, where we identified lithic implements in several different fluvial depositional morphologies. Preliminary geoarchaeological interpretation allows us to define five archaeological contexts formed by different alluvial processes.