Large geographic and temporal extensions of the Río de la Plata Craton, South America, and its metacratonic eastern margin

Integration of existing isotopic and geological data allows a reconsideration of the distribution and age of the Río de la Plata Craton within South America. The reinterpretation increases the area of the craton to about 2,400,000 km2 with implications for the tectonic map of South America and for global reconstruction of palaeocontinents. Four areas previously considered as separate cratons (Luís Alves, Curitiba, Tebicuary, and Paranapanema) are interpreted as part of the same Río de la Plata Craton. The craton is organized into six provinces and domains: Buenos Aires–Piedra Alta, Taquarembó, Tebicuary, Luís Alves, Encantadas, and Nico Pérez. The term ‘Transplatense’ is proposed to replace ‘Trans-Amazonian’ for Rhyacian events that occurred within the Río de la Plata Craton. The craton is formed not only by dominant Rhyacian rocks and local Archaean rocks, but also by Statherian and Mesoproterozoic rocks. The domains are all partially to totally covered by Phanerozoic basins (Paraná, Chacoparanense, Claromecó, Salado, Balcarce, and Colorado) which makes their investigation difficult. The Ediacaran–Cambrian collisions of the Brasilian orogen generated tectonic mixtures of orogenic and cratonic zones. This is more evident in the eastern margin of the craton, which behaved as a metacraton

Nuevos registros de Braquiópodos y consideraciones sobre las faunas de Tivertoniastreptorhynchus (Moscoviano) y Costatumulus amosi (Pérmico temprano) del oeste argentino: reexamen de las secciones clave de las Quebradas Agua del Jagüel y Santa Elena

The brachiopod Coolkilella aredesi sp. nov. and Calytrixia piersoni sp. nov. are proposed on the basis of specimens from the Del Salto, Río del Peñón and Agua del Jagüel formations. Their biostratigraphic implications are discussed together with new records of Septosyringothyris (Precosyringothyris) jaguelensis Lech and Streptorhynchus inaequiornatus Leanza at the top of the latter unit. The stratigraphic record, paleontological content and age of both the Tivertonia-Streptorhynchus assemblage (Moscovian) and the younger Costatumulus amosi fauna (Sakmarian–Artinskian) were reviewed and assessed based on outcrops at Quebrada Agua del Jagüel and Quebrada Santa Elena. Faunal content confirms the most recent stratigraphic, biostratigraphic and paleoclimatic frameworks. These a diachronic nature of the Agua del Jagüel and Cordón del Jagüel formations, supporting the absence of an early Permian glacial event in western Argentina.Se proponen las nuevas especies de braquiópodos Coolkilella aredesi sp. nov. y Calytrixia piersoni sp. nov. sobre la base de especímenes provenientes de las formaciones Del Salto, Río del Peñón y Agua del Jagüel. Se analizan sus implicancias bioestratigraficas junto al significado de nuevos registros de Septosyringothyris (Precosyringothyris) jaguelensis Lech y Streptorhynchus inaequiornatus Leanza en el techo de la última unidad mencionada. Se revisan y precisan el registro estratigráfico, contenido paleontológico y edades de la asociación de Tivertonia-Streptorhynchus (Moscoviano) y de la fauna más joven de Costatumulus amosi (Sakmariano—Artinskiano) en los afloramientos de las Quebradas de Agua de Jagüel y Santa Elena. El contenido faunístico permite corroborar los más recientes esquemas estratigráficos, bioestratigráficos y paleoclimáticos, reconociendo las formaciones Agua del Jagüel y Cordón del Jagüel como unidades diacrónicas y desestimando a su vez la existencia de un evento glacial Pérmico en el oeste de Argentina.Fil: Taboada, Arturo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Laboratorio de Investigaciones en Evolución y Biodiversidad; Argentin