Palinoestratigrafía y paleoambientes de estratos del Jurásico Temprano (Formación Nestares) en el norte de patagonia, Argentina

Abstract

A palynologic analysis is presented of the Early Jurassic Nestares Formation at its type locality, on both sides of the Limay river, Alicurá dam, at Neuquén and Río Negro provinces boundary, northern Patagonia, Argentina. In this first part the terrestrial species (spores and pollen grains) of the microflora are listed, illustrated and, in some cases, commented on. The geologic context is reviewed and different paleoenvironmental interpretations, one as a paralic sequence and another as an anastomosing fluvial system, both based on earlier sedimentologic studies, are considered. The microflora is compared with the known record of the megaflora and the botanical affinities of the components of the microflora are proposed. Thirty nine of the species of miospores illustrated and listed are recorded for the first time in the Early Jurassic of Argentina. The terrestrial taxonomic diversity is represented by 48 species of Bryophyte/Pteridophyte spores and 23 species of Gymnospermous pollen grains, versus five species of Pteridophytes and 17 Gymnosperm species known from the the megaflora; thus the microfloristic biodiversity record is larger than the megafloristic one. © Asociación Paleontológica Argentina.