[1] Univ Quebec, Earth & Atmospher Sci Dept, Lab Lux Geotop, Montreal, PQ, Canada
[2] Univ, Rock Art Res Inst, GAES, Johannesburg, South Africa
[3] Univ Quebec, Ctr Interuniv Etud Ies Iettres, Montreal, PQ, Canada
[4] Univ Oxford, Oxford Radiocarbon Accelerator Unit, Oxford, England
[5] Univ Oxford, Sch Archaeol, St Hughs Coll, Oxford, England