Quantitative sourcing of slackwater deposits at Boila rockshelter: A record of lateglacial flooding and paleolithic settlement in the Pindus Mountains, Northwest Greece

Evidence for large floods in the Pindus Mountains of Northwest Greece during the Lateglacial period is provided by a sequence of fine-grained slackwater sediments preserved beneath the Late Upper Paleolithic deposits at Boila rockshelter in the Voidomatis River basin. We have applied a quantitative sediment fingerprinting approach to estimate the relative contributions from different catchment sediment sources to these flood sediments. Our approach utilizes recent developments in hydrology and fluvial geomorphology where researchers have used sediment properties to establish the source of suspended sediments transported in rivers during present-day flood events. The data set used to create the composite sediment source fingerprint comprised nine tracer properties including eight trace elements (determined by X-ray fluorescence techniques) and magnetic susceptibility. The Boila sequence has been dated by conventional and AMS radiocarbon techniques, and the central and upper part of the flood sediments were deposited between ca. 14,310 +/- 200 and 13,960 +/- 260 radiocarbon yr B.P. These flood events took place during the global cooling associated with Heinrich event 1, although the sediment fingerprinting data indicate that glacial activity in the Voidomatis basin was no longer supplying large volumes of sediment to the fluvial system at this time. The slackwater deposits are mainly derived from flysch sediments and soils from nonglaciated parts of the Voidomatis River basin. The results of this approach compare well with lithological estimates based on micromorphological analyses and are in good agreement with existing data on the Late Pleistocene and Holocene behavior of this river system. The slackwater sediments offer important insights into the nature of the river environment and the wider catchment system during the Lateglacial period when the Klithi rockshelter (ca. 2 km upstream of Boila) was the focus of Paleolithic activity in the Voidomatis Gorge. In appropriate depositional contexts, quantitative sediment fingerprinting constitutes a valuable geoarchaeological tool for the investigation of rockshelter and cave sediment records that can improve our understanding of site formation processes and their broader environmental context. This approach is a valuable complement to the micromorphological investigation of rockshelter sediment records. (C) 2001 John, Wiley & Sons, Inc.