Abstract

ZAVATTIERI, Ana María  and  MEGO, Natalia. Palynological record of the Paso Flores Formation (Late Triassic) on the southeastern side of the Limay River, Patagonia, Argentina. Ameghiniana [online]. 2008, vol.45, n.2, pp.483-502. ISSN 1851-8044.

Well-preserved spore-pollen assemblages from the type locality of the Paso Flores Formation, in the Estancia Paso Flores area, on the southeastern side of the Limay River, northern Patagonia, Argentina, are presented in this contribution. In this area, the Paso Flores Formation is exposed along the boundary between the Río Negro and Neuquén provinces; it consists mainly of conglomerates, sandstones and mudstones and contains remains of the Dicroidium Flora. The facies associations suggest gravelly to sandy braided river systems as the main depositional environments of the lower to middle sections of the unit outcropping in this region. The palynofloral assemblages contain 48 species of bryophytic and pteridophytic spores, 30 species of gymnospermous pollen grains, and chlorophytic algal remains, most of which are illustrated herein. New forms belonging to the genera Cadargasporites, Neoraistrickia, Perotrilites, Verrucosisporites, Equisetosporites, and Steevesipollenites are described. Anapiculatisporites dawsonensis Reiser and Williams, Biretisporites sp. and Thymospora cicatricosa (Balme and Hennelly) Hart are also described and discussed. The miospore assemblages conform to the Ipswich phytogeographic province of the Gondwanan Triassic. Within this province, the Paso Flores assemblages are correlated compositionally and chronostratigraphically with the Craterisporites rotundus Oppel Zone of eastern Australian continental sequences. Thus, a Late Triassic (Late Carnian-Early Norian) age is established for the palynoflora of the lower section of the Paso Flores Formation.

Keywords : Palynology; Upper Triassic; Paso Flores Formation; Patagonia; Argentina.