Datation uranium/thorium et analyse pollinique d'une séquence stalagmitique du stade isotopique 5 (Galerie des Verviétois, Grotte de Han-sur-Lesse, Belgique)

The stalagmitic body of the «Galerie des Vervietois» («Grotte de Han», Belgium) has been sampled by numerous drillings. We present here two series studied by lithostratigraphy, palynology and absolute dating by the uranium series disequilibrium. These series allow one to date and reconstitute the palaeoclimatic sequence from isotopic substage 5.5 to isotopic substage 5.3, emphasizing the climatic deterioration of the isotopic substage 5,4 (Melisey I in the «Grande Pile» sequence)