Pollen record of megathermal and mesothermal elements in the late Pliocene from west Portugal revealed by combined light and scanning electron microscopy studies

Abstract

The Rio Maior deposits, part of the Tagus Basin located in western Portugal, are comprised of sediments from late Pliocene to earliest Gelasian age. Using combined light and scanning electron microscopy, we report, for the first time, nine important taxa in late Pliocene, Piacenzian sediments from south-western Europe. Eight pollen-taxa (Cercidiphyllum, Craigia, Mortoniodendron, Diplopanax, Zanthoxylum, Sapotaceae, Sideroxylon and Leitneria) belong to extant plant groups currently living in tropical to temperate areas. The record of Trigonobalanopsis represents an extinct genus in the oak family (Fagaceae). The records of these taxa indicate the presence of a warm-temperate mixed forest during most parts of the Piacenzian at this latitude.