STRATIGRAPHY AND DEPOSITIONAL ENVIRONMENTS OF THE SANTA CRUZ FORMATION (EARLY-MIDDLE MIOCENE) ALONG THE RÍO SANTA CRUZ, SOUTHERN PATAGONIA, ARGENTINA

RAIGEMBORN, MARIA SOL; CUITIÑO, JOSÉ I.; KRAPOVICKAS, VERÓNICA; FERNÍCOLA, JUAN CARLOS

Publicación Electrónica de la Asociación Paleontológica Argentina

ASOCIACIÓN PALEONTOLOGICA ARGENTINA

Lugar: CABA; Año: 2019 vol. 19 p. 14 - 33

The Santa Cruz Formation is an Early?Middle Miocene terrestrial sedimentary succession widely distributed in southern Patagonia. Particularly, it is exposed along the southern margin of the Río Santa Cruz valley where the sedimentological and stratigraphical features are described for three localities. From east to west these localities are: Barrancas Blancas, Segundas Barrancas Blancas and Yaten Huageno. The facies analysis permits us to identify three associations, representing deposition in 1) low-energy floodplains; 2) crevasse splays and sheet floods; and 3) fluvial channels. The three localities are chronologically equivalent and represent accumulation in an aggradational lowgradient fluvial system that drained towards the east and northeast from the Patagonian Andes to the Atlantic sea. Abundant pedogenic features and some trace fossils are consistent with a temperate subhumid climate and in part, a grassland environment.