Estratigrafía y vertebrados (Aves y Mammalia) de la Formación Cerro Bandera, Mioceno Temprano de la Provincia del Neuquén, Argentina

KRAMARZ, A.; GARRIDO, A.; FORASIEPI, A. M.; BOND, M.; TAMBUSSI, C

REVISTA GEOLóGICA DE CHILE

Servicio Nacional de Geologia y Mineria

Lugar: Santiago, Chile; Año: 2005 vol. 32 p. 273 - 291

0716-0208

The Cerro Bandera Formation comprises a series of isolated outcrops that represent the relicts of an old sedimentary filling developed on small local valleys. It is composed of a succession of reworked pyroclastic deposits alternating with primary pyroclastic and scant sandstone levels. These deposits were originally recognized at the northeast of Barda Negra, south of Cerro Bandera and northwest of Sierra del Portezuelo; new exposures are herein recognised on the northwestern slope of Cerro Bayo Mesa, Neuquén Province, Argentina. The recovered fossil remains correspond to birds (Falconidae) and 17 families of mammals, among which are remarkable Cramauchenia normalis Ameghino, Proadinotherium cf. P. muensteri (Ameghino), Eosteiromys sp. and Caviocricetus lucasi (Vucetich y Verzi), plus a species of Protypotherium with more primitive dentition than those known of the Santacrucian Age. This association confirms a Colhuehuapian SALMA (early Miocene) for this unit. This fauna is markedly different from that recorded from the lower section of the Chichinales Formation, Rio Negro Province. The degree of faunistic differentiation between these probably synchronous units could be a result of local palaeoenvironmental differences.