Bioestratigrafía de polen y esporas de la Formación Chenque, Oligoceno tardío?-Mioceno de las provincias de Chubut y Santa Cruz, Patagonia, Argentina

BARREDA, V. D.

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 1996 vol. 33 p. 35 - 56

0002-7014

ABSTRACT:POLLEN AND SPORES BIOSTRATIGRAPHY OF THE CHENQUE FORMATION, LATE OLIGOCENE?-MIOCENE FROM CHUBUT AND SANTA CRUZ PROVINCES, PATAGONIA, ARGENTINA. Spore-polIen assemblagesrecovered from the Chenque Formation were analysed. Four informal biostratigraphic zones were defined, viz. lower zone (A),transition zone (T), middle zone (B) and upper zone (C). A Late Oligocene? - Early to Middle? Miocene age is assigned to theChenque Forrnation. The Patagonian spore-polIen assemblages are similar to those of Late Oligocene and mainly Miocene age ofNew Zealand, Australia and Antarctica. Fossil spore-polIen assemblages of tropical America are less similar. Tree polIen ofPodocarpaceae, Fagaceae and Araucariaceae is comrnon; it probably developed in higher or more remote lands than most herbaceousand shrub forms. Chenopodiaceae, Ephedraceae, Restionaceae and Sparganiaceae are frequent and may have Iived in acoastal-estuarine-saltmarsh environment. These habitats appear to be better developed in the upper part of the Formation (C zone).Other families such as Compositae, Malvaceae, Gramineae, Polygonaceae, Goodeniaceae, Onagraceae, Anacardiaceae,Escalloniaceae and Gunneraceae are present, but in a lower proportion. These spore-polIen assemblages suggest a humid andtemperate to warm temperate c1imate.