MIDDLE DARRIWILIAN CONODONT BIOSTRATIGRAPHY OF THE VILLICUM RANGE, EASTERN PRECORDILLERA, ARGENTINA

MESTRE, A.

PUBLICACION ESPECIAL - ASOCIACION PALEONTOLOGICA ARGENTINA

ASOCIACIÓN PALEONTOLÓGICA ARGENTINA

Lugar: Buenos Aires; Año: 2013 vol. 13 p. 69 - 72

0328-347X

THE top of the San Juan Formation in Villicúm range has long been described and discussed to emphasis usually being placed on stratigraphy and macrofossils (Baldis and Beresi, 1981; Sánchez et al.,1996; Peralta and Beresi, 1999; Kröger et al., 2007). Sarmiento (1985, 1987) represented the first contributions on conodont biostratigraphy of the San Juan and Los Azules formations in Don Braulio and La Pola creeks, where she recognized the "Amorphognathus variabilis-Eoplacognathus pseudoplanus"  Zone. Subsequently, Sarmiento (1990, 1991) reviewed this conodont fauna and recorded the E. suecicus Zone for these levels. Recently, Heredia and Mestre (2011) proposed a new biostratigraphic chart for the Precordillera, documenting the Lenodus variabilis Zone, Yangtzeplacognathus crassus Zone, Eoplacognathus pseudoplanus Zone and Eoplacognathus suecicus Zone, that confirm the close connection with those of Baltica and South-Central China. The present work is an early contribution about records of the conodont fauna of Villicúm range in three sections such as Don Braulio, La Pola and Cecilia creeks (Fig. 1), proposing for first time in this sector of the Precordillera basin the Yangtzeplacognathus crassus Zone in the very top of San Juan Formation.