Cambrian-Ordovician sponges and spicule assemblages from norwest Argentina: New data from the siliciclastic platforms of western Gondwana

BERESI, M., ACEÑOLAZA, G. Y NIEVA, S.

Neues Jahrbuch fur Geologie und Palaontologie

Schweiz. Verlagsbuchhandlung

Lugar: Stuttgart; Año: 2006 p. 403 - 420

0077-7749

This study provides the first report of Cambro/Ordovician sponges in the Sierras Subandinas, and a new locality with spicule assemblages in the Cordillera Oriental of Northern Argentina and the Eopaleozoic Central Andean Basin of South America. The part and counterpart of a complete rounded thin-walled sponge assigned to Diagoniella sp. was recovered along abundant fragmentary material in the shales of the Orcomato Formation cropping out at the Sierra de la Candelaria of southern Salta Province. Associated fauna suggest a Furongian? – Early Ordovician age for the unit. In addition, a spicule assemblage preserved on sandstone slabs was found in the lower levels of the Saladillo Formation, at the Angosto de la Quesera in the Cordillera Oriental of Salta Province. Spicules share stratigraphic position with the graptolite Bryograptus kjerulfi, resticting its age to an early Upper Tremadocian. The recognition of the first protospongiid in the Sierras Subandinas and the record of an additional spicule assemblage in the Cordillera Oriental of Northern Argentina provides valuable information on the spreading of the protosponges in the Lower Paleozoic seas of western Gondwana.