TL dating of Upper Palaeolithic sites in the Coa Valley (Portugal)

In 1992, numerous animal engravings in styles associated with the Upper Pal aeolithic (Gravetian to Magdalenian) were discovered along a long stretch o f the schist cliffs bordering the Coa Valley (Northern Portugal). This sugg ested that not only caves and rock-shelters but also open-air Pleistocene s ites may have been decorated in this manner more often than previously beli eved. Attempts to date the engravings themselves (radiocarbon of patination , micro-erosion analysis) were unsatisfactory, yielding contradictory and w idely scattered dates. We are now reporting thermoluminescence ages of 15 burnt quartzite pebbles excavated in 1997 at three sites (Cardina, Olga Grande Sul, Quinta da Barca Sul) near the decorated cliffs. The ages of the Cardina and Olga Grande Su l pebbles indicated human presence at the sites between 30 and 27 ka ago, d uring the Gravetian period. The Quinta da Barca Sul pebbles were 13-10 ka o ld, indicating that humans were also present in the Valley during the Magda lenian period. (C) 2000 Elsevier Science Ltd. All rights reserved.