Palaeoenvironmental and archaeological interest of late glacial colluvial deposits in the middle part of the Tonaro River valley, province of Cuneo (southern Piedmont, NW Italy)

Abstract

The genesis and possible palaeoclimatic and palaeoenvironmental significance of a colluvial deposit confined to the top edges of a river terrace, in the middle valley of the Tanaro river, are discussed. This deposit has a silty-clayey texture and a lenticular shape (maximum thickness 80-90 cm). Position and texture suggest that the deposit formed under climatic conditions comparable to those prevailing in the Wurm Pleniglacial/Late Glacial, as defined in the European alpine and continental palaeoclimatic sequences. Under such palaeoclimatic conditions, local deposition/erosion episodes controlled by different surface runoffs governed by rainfall variations, can be hypothesised. Buried or disseminated stone artifacts in the examined archaeological site, may be evidence of different colluvial proces-ses, developed between the Late Glacial and the present, during which coarser clastic material was either preserved insitu or transported downhill. A Late Glacial age of the colluvial layers fits the archaeological tradition of the artifacts. Like other sediments such as loess and grezes litees, colluvial deposits seem to hold evidence of the local climate, and may therefore offer palaeoenvironmental and archaeological records of a time period that is generally very poorly represented by plain deposits.