Microbraquiópodos Inarticulados del techo de la Formación San Juan (Darriwiliano Medio), Precordillera Central.

LAVIÉ, FERNANDO J.; MESTRE, ANA; CARRERA, MARCELO G.

Congreso; XX Congreso Geológico Argentino; 2017

Inarticulate microbrachiopods from the top of the San Juan Formation (Middle Darriwilian), Central Precordillera. Two associations of inarticulate microbrachiopods were recovered from the very top of the San Juan Formation cropping out at the Quebrada de la Brecha and Cerro La Chilca sections (Central Precordillera). These levels of the San Juan Formation are assigned to the Eoplacoganthus pseudoplanus conodont Zone. The rich Acrotretidae inarticulate microbrachiopods association the Cerro La Chilca sample, is composed mostly by the genus Numericoma Popov. On the other hand, the association retrieved from the Quebrada de la Brecha sample is only represented by the obolid Pidiobolus Mergl. The Cerro La Chilca assemblage could indicate low energy environment of the middle-outer ramp setting and the Quebrada de la Brecha assemblage could represent a high energy environment of the middle-outer ramp.