Nueva microflora de edad maastrichtiana en la localidad de Calmu-Co, sur de Mendoza, Argentina

Abstract

A new palynornorph bearing locality in the Loncoche Formation at Calmu-Co creek, southern Mendoza, is presented. The stratigraphic sequence is 150 m thick and composed of pelites, sandstones, conglomeratic sandstones, gypsum and marls. From the fine grained levels two microfloristic associations, together with megafloral remains, have been recovered. The prevailing taxa are pteridophyte spores of the farnilies Osmundaceae, Hymenophyllaceae, Gleicheniaceae, Matoniaceae, Cyatheaceae, Salviniaceae, Isoetaceae, Selaginellaceae and Lycopodiaceae. The arboreal vegetation is represented by rare pollen grains referable to the Podocarpaceae, Araucariaceae, Cheirolepidiaceae and Fagaceae families. The most representative angiosperrn families are the Gunneraceae, Proteaceae and Liliaceae/Iridaceae. Freshwater algae, such as Botryococcus, are abundant; in contrast, cenobia of Pediastrum and Scenedesmus are very scarce. CuticJes of seeds have been preliminarily assigned to the genus Costatheca. The sediments bearing the microflora were deposited in a fluvial environment with meandering rivers and a system of lagoons situated within the fluvial flood-plain.