La significación de las faunas de invertebrados marinos del Triásico Superior de Sudamérica meridional

DAMBORENEA, S.E.; RICCARDI, A.C; MANCEÑIDO, M.O.; CAMPBELL, H.

Santiago de Chile

Congreso; XII Congreso Geológico Chileno; 2009

Universidad de Chile

   Modern knowledge about South American Late Triassic marine faunas is reviewed and updated. Among recent advances, a remarkable Rhaetian invertebrate fauna was recovered from the Atuel River area (central-western Argentina). There the Arroyo Malo Fm has yielded an important assemblage containing heteromorph ammonoids, bivalves, gastropods, brachiopods, nautiloids and cnidarians. Affinities with other South American faunas of roughly equivalent age, include those from the Profeta Fm from Cordillera Domeyko–Sierra de Varas (northern Chile), and from the Pucará Group (central and northern Peru). The Pucará Group also contains somewhat older, monotid-bearing faunas, yet unknown in Argentina, but previously recorded from Peru (Utcubamba Valley, Cerro de Pasco–Huancayo region), and elsewhere, apparently reaching as far south as the Chonos Archipelago (southern Chile). Another interesting molluscan fauna has been reported from the Biobío area (south-central Chile) and dated as late Carnian? to early Norian.