Permian palynofloral changes in Uruguay and their relationships with lithostratigraphic units

A total of 77 samples from Permian strata of Uruguay were extracted from eight boreholes drilled by Dirección Nacional de Minería y Geología of Uruguay, as well as from two outcrops located in El Barón Creek (1 sample) and on Route 26, east of Melo City (1 sample). These samples correspond to the San Gregorio-Cerro Pelado, Tres Islas, Fraile Muerto, Mangrullo and Paso Aguiar Formations from the early Cisuralian to approximately the early Guadalupian. To quantify change in palynological assemblages, 188 species of sporomorphs were identified and binned by geological formations. Extinction and originations were calculated between formations. There was no qualitative change in species composition in the San Gregorio-Cerro Pelado, Tres Islas and Fraile Muerto Formations. A turnover in sporomorph species assemblage was observed between the Fraile Muerto and the Mangrullo Formation, which coincides temporally with the onset of an arid climatic phase for the region. Plant assemblages were analysed taking into account that the botanical affinities of the sporomorphs show no significant change through the sampled time interval.