Palynology of the lower permian of Paraná Basin, Uruguay

Abstract

The palynological contents of the Permian Tres Islas and Melo formations (Frayle Muerto, Mangrullo and Paso Aguiar members), obtained from boreholes and outcrop in northeastern Uruguay, are reported. These Permian sediments of the Paraná Basin yielded a total of 147 species, including the following new taxa: Archangelskiapollenites globocorpus gen. et sp. nov., A. plicatus gen. et sp. nov., Satsangisaccites uruguaiensis sp. nov. and Platysaccus orientalis sp. nov. The palynomorphs found allow identification, in borehole 221, of two palynological assemblages: 221-I (140-225 m) and 221-II (93-140 m); the former is characterised by the presence of Murospora torifera Ybert, Vallatisporites arcuatus Archangelsky & Gamerro and Lundbladispora areolata Césari et al., whereas assemblage 221-II contains Corisaccites alutas Venkatachala & Kar, Lueckisporites stenotaeniatus Menéndez, L. virkkiae Potonié & Klaus, L. angoulaensis Jardiné, Lunatisporites variesectus Archangelsky & Gamerro, Striatoabieites anaverrucosus Archangelsky & Gamerro and Staurosaccites cordubensis Archangelsky & Gamerro, among others. In borehole 201, two assemblages were also identified: 201-I (34 and 93 m) and 201-II (5 and 34 m). The former is typified by the presence of Cristatisporites chacoparanensis Ottone, C. lestai Archangelsky & Gamerro, Leiotriletes corius Kar & Bose, Murospora torifera, M. bicingulata Ybert, Vallatisporites arcuatus, V. russoi Archangelsky & Gamerro, Illinites unicus Kosanke, Limitisporites hexagonalis Maheswari and Protohaploxypinus bhardwajii Foster among others. Assemblage 201-II is characterized by the presence of Brevitriletes levis (Balme & Hennelly) Bharadwaj & Srivastava, Pakhapites fusus (Bose & Kar) Menéndez, P. ovatus (Bose & Kar) García, Platysaccus papilionis Potonié & Klaus, Protohaploxypinus limpidus (Balme & Hennelly) Balme & Playford, Striatopodocarpites cancellatus (Balme & Hennelly) Hart and Polarisaccites bilateralis Ybert & Marques-Toigo. Based on the previous records of those taxa, assemblages 221-I, 201-I and 201-II are assigned to the Early Permian (Asselian-Artinskian) and assemblage 221-II to the upper part of the Early Permian (Artinskian-Kungurian). According to the stratigraphical schemes of Argentina and Brazil, they are correlated with the Biozones Cristatisporites (assemblages 221-I, 201-I and 201-II) and Striatites (assemblage 221-II and El Barón) (Chacoparaná Basin), Fusacolpites fusus-Vittatina subsaccata (assemblages 221-I, 201-I and 201-II) and Lueckisporites-Weylandites (assemblage 221-II and El Barón) (Paganzo Basin), and Vittatina costabilis (assemblages 221-I, 201-I and 201-II) and Lueckisporites virkkiae (assemblage 221-II and El Barón) (Paraná Basin).