NEW CONTRIBUTIONS TO PALYNOLOGY OF THE FRAYLE MUERTO, MANGRULLO AND PASO AGUIAR FORMATIONS, UPPER PALEOZOIC, URUGUAY

Abstract

Palynological content of nine samples extracted from borehole N° 254 “Paso de las Toscas”(DI.NA.MI.GE.) is analyzed. The samples derived from the Frayle Muerto, Mangrullo and Paso Aguiar formations, Permian in age. A total of 123 species were identified. This paper presents a systematic analysis of 25 species that are new records for Uruguay. Twelve of these species are assigned to spores, seven to pollen grains and six to acritarchs. Pollen grains are dominant in all assemblages except in the lower stratigraphic levels. Spores are present in relatively high proportions only at the lower and upper levels. Acritarchs and reworked material are found in two samples. The comparison of palynological assemblages with regional palynostratigraphic schemes suggests a Cisuralian age (probably Asselian-Artinskian) for the lower stratigraphic level (Cristatisporites Biozone for Argentina, Vittatina costabilis Biozone for Brasil and Cristatisporites inconstans–Vittatina saccata Biozone for Uruguay) and an age between the late Cisuralian and the Guadalupian for the remaining levels (Striatites Biozone for Argentina, Lueckisporites virkkiae Biozone for Brasil and Striatoabieites anaverrucosus – Staurosaccites cordubensis Biozone for Uruguay).