As unidades pliocénicas e quaternárias no espaço do Baixo Mondego (uma perspectiva de ordem)

Abstract

Pliocene and Quaternary Units in the Lower Mondego (Portugal) — The analysis of the relations betweenthe quaternary deposits in the Baixo Mondego, as well as their individualisation from others considered asPliocene, still suffer from insufficient reference marks necessary to guarantee equivalencies. The limitis now considered to be in the concert of the Cruz de Morouços Complex, where the Antanhol Formation(= Barracão Group, Upper Pliocene) and the Espírito Santo Conglomerate, equivalent to the GordosConglomerate (Lower Pleistocene), succeed to each other. From the Pleistocene assemblage andbeside the deposits directly associated to the evolution of Mondego (Ameal-Santo Varão and Tentugal-Gabrielos deposits), the deposits revealing upper littoral environments stand out, as the ArazedeSandstone, the Quiaios Sandstone, others deposits directly related with the Cabo Mondego morphogenesis,the Farol Deposits, fossiliferous and possibly from the Lower to Middle Pleistocene and theMurtinheira Deposits from the Upper Pleistocene. In turn the Condeixa Tuffs, with an accommodationspace of 24 Km2 , show an ordered succession of facies (Conglomerates — Cg; yellow mud — Pa, tuffs— Ta and Tc; grey mud with Lymnea — Pc) and an extended age from the Pleistocene (with Elephasantiquus and Hippopotamus incognitus in the base) possibly around the 400 Ka, to the Holocene (faciesPc with roman archaeological remains).