A NEW EARLY JURASSIC MARINE LOCALITY FROM SOUTHWESTERN CHUBUT BASIN, ARGENTINA

FERRARI, S.M; BESSONE, S.

ANDEAN GEOLOGY

SERVICIO NACIONAL GEOLOGIA MINERVA

Lugar: Santiago de Chile; Año: 2015 vol. 42 p. 349 - 363

0718-7092

A shallow marine invertebrate association is reported from a new EarlyJurassic locality, La Casilda, in the southwestern region of the Chubut Basin(Patagonia, Argentina). The marine deposits of La Casilda are located in theRio Genoa valley and bear a diverse invertebrate fauna including bivalves,gastropods, brachiopods, echinoderms and corals. A preliminary taxonomic analysisof the invertebrate fauna suggests that La Casilda deposits belong to theMulanguiñeu Formation of late Pliensbachian?early Toarcian age, and may be coevalwith those from the marine localities previously sampled in other regions of theRío Genoa valley. The preliminary results of a biodiversity analysis displayedthat La Casilda is one of the most diverse localities at the Chubut Basin. Theevolution of the marine transgression during the early Pliensbachian?earlyToarcian is also interpreted here in a time scale based on ammonite faunas, givinga temporal reconstruction of the entire Chubut Basin.