Étude palynologique du passage Albien moyen-Albien supérieur du Bassin de Tarfaya (Sud-Ouest du Maroc) et nouvelles Données sur la province Afro-Sud-Américaine

Abstract

The palynological study of samples from a section of presumed Late Albian age in the Tarfaya Basin provided rich and well preserved continental and marine microfloras. Among the continental sporomorphs, 75 species have been found of which 16 Gymnosperms, 31 Angiosperms, 19 spores of Pteridophyta and 9 elaters-bearing sporomorphs. The association of several stratigraphic good marker taxa precises that the age of the studied levels is the Middle Albian-Late Albian transition. Concerning the paleoclimatology, this study contributes to a better knowledge of the relationships between the different floristic provinces defined during the Lower / Upper Cretaceous transition. Thus, the African-South-American province ( Herngreen and Chlonova, 1981) occupied a vast area under an uniform climate, hot and probably humid in which the elater-bearing sporomorphs spread out, their fast expansion resulting perhaps of the pollination by the insects. The spectacular decline of these taxa, at the end of the Cenomanian, suggests the thermophile and probably hygdrophilous characters of their mother plants. Up to the Upper Albian, the Tarfaya Basin was situated in the northern part of the province, under an humid climate like this of paleoequator, but nevertheless influenced by the South of the boreal province.