Noves dades sobre les relacions paleogeogràfiques del massís del Port del Comte amb les Serres marginals sud-pirinenques (Pirineu català, Espanya)

Abstract

New data about the paleogeographic relationship between the Port del Comte massif and the South Pyrenean marginal ranges (Catalonian Pyrenees, Spain).

Stratigraphic analysis of the Mesozoic – Cenozoic time of the South Pyrenean marginal ranges (Serres marginals) NE of Balaguer and the Port del Comte massif (Pedraforca Unit s.l..), to the W and the E of Segre river, respectively, allow us to confirm the two units belonged to the same paleogeographic area until the end of the Cuisian time. This is demonstrated by the different characteristic levels: postjurassic bauxites; similar lithologic and chronologic features of the firts deposits of the Senonian transgression; specific finicretaceous horizons of heavy minerals and presence of the Lower Eocene fluviomarine episode. We conclude that in the Cuisian, the eocene sea which overran the structural south Pyrenean troughs was divided by interposition of various tectonic elements, into a western basin (Graus – Tremp) and an eastern basin, to which the units
studied in this paper were related.