CONSTRAINING THE TIMING OF ALLUVIAL-FAN RESPONSE TO LATE QUATERNARY CLIMATIC CHANGES, SOUTHERN TUNISIA

The evolution of the Cued es Seffaia alluvial fan during the last 50,0 00 years is analyzed in the light of chronometric data derived from AM S radiocarbon and optical dating techniques. These ages have enabled t he temporal constraint of the distalward progression of the intersecti on point (the upper limit of the locus of deposition) which has result ed in the telescopic segmentation of the fan. Comparison of these data with the Late Quatemary climatic history of the Maghreb highlights se veral problems of interpretation; due both to our limited knowledge of regional palaeoclimates and of the response of dryland fluvial system s to climate changes. However, our data provide some evidence to sugge st that fan incision and formation of telescopic segments occurs in re sponse to changes from arid to less arid conditions, supporting the co nclusions of some of the work from other areas.