Reconstrucción de paleocomunidades arbóreas mediante análisis fitolíticos en sedimentos del Paleoceno superior-Eoceno? (Formación Las Flores), Chubut, Argentina

BREA, M.; ZUCOL, A.; RAIGEMBORN, M. S.; MATHEOS, S. D.

Interdisciplinary Nuances in Phytolith and other Microfossil Studies

BAR (British Archaeological Reports) Internacional Series

Lugar: Oxford, Inglaterra; Año: 2008; p. 91 - 108

In the Golfo San Jorge basin (Chubut, Central Patagonia, Argentina), during the Upper Paleocene-Eocene?, an important fluvial cycle was developed, whose sediments have been called the Rio Chico Group. This Group consists of three formations: Peñas Coloradas, Las Flores and Koluél Kaike. The sedimentary samples analyzed in this study come from Lake Colhué Huapi in the Gran Barranca area (45° 43’ 26’’ S and 68° 37’ 14’’ W). Two phytolith zones were identified in core samples from Upper Paleocene-Eocene? sediments, with phytolith assemblages characterized by an abundance of dicotyledons phytoliths and palm phytoliths, in association with Poaceae, Cyperaceae and Podostemaceae phytoliths. Siliceous sponge spicules, Chrysostomataceae stomatocycts and diatoms also occured in these assemblages. Nine plant families and one order were recognized: Arecaceae, Chrysobalanaceae, Mimosaceae, Magnoliaceae, Annonaceae, Burseraceae, Zingiberales, Poaceae, Cyperaceae y Podostemaceae. The two phytolith zones reflect palaeovegetation patterns consisting of humid tropical and subtropical forests, with one dominated by woody dicotyledoneous taxa and the other by palms, and which were developed under warm and humid climatic conditions. These interpretations of past climatic conditions are supported by other lines of evidence, including the nature of the sediments in the sequences studied and wood identification data.