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Strontium isotopic and petrologic information, obtained from sediment cores collected in the Nile delta of Egypt, indicate that paleoclimatic and Nile baseflow conditions changed considerably from about 4200 to 4000 cal yr B.P. in the Nile basin. Our study records a higher proportion of White Nile sediment transported during the annual floods at ca. 6100 cal yr B.P. than towards 4200 cal yr B.P., at which time suspended sediment from the Blue Nile formed a significantly larger fraction of the total load. This resulted from a decrease in vegetative cover and an increase in erosion rate accompanying the marked decline in rainfall. These new geoscience data indicate major changes in annual flooding and baseflow of the river Nile, marked short-term paleoclimatic-related events that may in part have led to the collapse of the Old Kingdom. © 2003 Wiley Periodicals, Inc.

It is important to develop rigorous methods and robust conceptual models for the interpretation of rockshelter and cave sediment records so that the cultural sequences they contain can be considered in their proper environmental context. Much of what we know about the prehistory of the Mediterranean region and adjacent areas has largely been pieced together from materials excavated from sedimentary sequences in these environments. The rockshelters and caves of the region form important environmental and sedimentary archives. Recent work has begun to consider if the remarkable climatic variability evident in the high resolution lacustrine and ice core records is manifest in the rocksheiter and cave sediment records of the area. In this context, the two main characteristics of a rockshelter or cave site which control its usefulness as an archive of environmental change are the temporal resolution of the sedimentary record and the environmental sensitivity of the site. Many rockshelters and caves can be described as either Active Karst Settings (AKS) or Passive Karst Settings (PKS) and site type is an important influence on climatic sensitivity with a direct influence upon the usefulness of the sedimentary sequence as a proxy record of climate change. It is now clear that some sites may preserve detailed paleoclimatic records and the climatic signal may be represented by distinctive suites of micromorphological features, by variations in the input of allogenic sediment, or by fluctuations in the mineral magnetic properties of the fine sediment fraction. It can be argued that data derived from the analysis of bulk coarse-grained samples often lacks the stratigraphic resolution and environmental sensitivity that can be obtained from other approaches. The most favorable sites for detailed paleoclimatic reconstruction appear to be in active karst settings such as Theopetra Cave (Greece) and Pigeon Cave (Morocco) where micromorphological analyses offer insights into the stratigraphic record that are not otherwise obtainable. The temporal resolution of a site can only be established through a rigorous stratigraphic analysis and a comprehensive dating program. These are fundamental considerations in the study of rockshelter sediment records, especially when attempting to correlate between sites and draw comparisons with other proxy records of environmental change derived from sedimentary environments with rather different characteristics. Rockshelters and caves are part of a wider sediment system, and their investigation must be accompanied by detailed geomorphological, sedimentological, paleoecological, and geochronological studies of the off-site Quaternary record. © 2001 John Wiley & Sons, Inc.

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. © 2001 John Wiley & Sons, Inc.