Multidisciplinary study of the quaternary deposits of the Vila Nova de Gaia, NW Portugal, and its climate significance

Abstract

Palynological, geochronological, and sedimentological analyses were conducted on samples from different depositional units of well-preserved marine, fluvial and palustrine sedimentary deposits from Vila Nova de Gaia located at the northwestern Portuguese coast. The studied deposits occur on two terraces: Terrace A—Lavadores (18 m to 33 m) and Terrace B—Canidelo (50 m). Chronological and sedimentological features allowed to date the deposits to the Upper Pleistocene until the last glacial period, being observed an evolution from a depositional setting in a marine intertidal zone, passing to a fluvial environment and ending in a palustrine/lagunar environment with possible periglacial influence. Pollen assemblages collected in the fluvial sedimentary horizons also suggested changes in the environmental conditions. A pollen content with good representation of arboreal species (Quercus, Pinus, Castanea, Fraxinus, Salix, Betula and Corylus), changed to a vegetation environment dominated by non-arboreal species, such as Poaceae, Plantago and Asteraceae. The top horizons, corresponding to a palustrine/lagunar environment, presented a pollen profile completely dominated by non-arboreal species, with minimal tree representation (Prunus, Quercus, Pinus and Castanea) which, combined with sedimentological characteristics may point to a more dry and cold climate than nowadays.