Palynology of the Las Curtiembres Formation (Late Cretaceous, Salta Group Basin), Las Conchas Creek area, northwestern Argentina

Abstract

This study provides the first palynologic record of the Las Curtiembres Formation (Late Cretaceous, Salta Group Basin) in northwestern Argentina. Two palynologically productive samples were obtained from the Morales Member in the area of the Las Conchas creek, Salta Province. Nineteen morphospecies are recorded for the Formation. The samples show poor preservation of the specimens and low diversity. The palynomorph association is characterized by the prevalence of species that belong to the Ephedraceae (6 species with 57% of total abundance), possibly suggesting semiarid conditions and a warm-dry paleoclimate at the time of deposition. Low humidity could also be inferred from the low abundance and diversity of pteridophyte species and the presence of Cheirolepidiaceae (Classopollis sp.) and Proteaceae (Peninsulapollis gillii (Cookson) Dettmann and Jarzen). The pollen grain Peninsulapollis gillii is a chronostratigraphic indicator of an age not older than Campanian-Maastrichtian, which would be coincident with the previous dating (77±5 Ma) of the Las Conchas Basalt effusions.