ACRITARCAS y PRASINOFÍCEAS DEL LLANDOVERIANO TEMPRANO MEDIO DE LA FORMACIÓN LA CHILCA, QUEBRADA DE TALACASTO, PROVINCIA DE SAN JUAN, ARGENTINA

Edna D. Pothe de Baldis

Abstract


"Forty nine species of acritarchs and prasinophyceae belonging ro twenty eight genera, from the upper part of the Salto Macho Member of the La Chilca Formation, in the Talacasto Creek are described. Diexallophasis sanpetrensis (Cramer) varo echinata n. var., Ozotobrachion lunense n.sp. and Priscogalea varispinosa n.sp. are presented. The presence of Tylotopalla robustispinosa (Downie) Eisenack el al. and Oppilatala eoplanktonica (Eisenack) Dorning, which mark acritarch biozones in Great Britain, suggests an early to middle Llandoverian age for the assemblage. The association has a high cosmopolitan characteristic. Forms with a wide stratigraphic range appearing since Ordovician times have a connection with nOI1hAfrican and continental European gondwanic areas; the younger Silurian forms, show more affinities with those of perigondwanic areas from the United States and Great Britain."

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