Resumo

KOUKHARSKY, Magdalena  e  OTTONE, Eduardo G. Fossil plants from the Choiyoi Group, Frontal Cordillera at the latitude of  the Mendoza River. Rev. Asoc. Geol. Argent. [online]. 2011, vol.68, n.2, pp.205-209. ISSN 0004-4822.

In  this  contribution we  report  the  discovery  of   the  first  fossil  remains  in  sedimentary  strata  belonging  to  the Tambillos Formation, Choiyoi Group, Cordillera Frontal of  Mendoza. In the studied area the Tambillos Formation, which is formed dominantly by acid volcanics rocks of  alleged Early to the Middle Permian, were deposited over an erosive unconformity on top of  propilytic andesites of  the Portezuelo del Cenizo Formation. The vegetal remains were found about 23 meters from the base of  the formation, hosted in fine-grained sandstones and shales that were deposited in a fluvial environment (microdelta), along  the borders of  a  lake during  the first episodes of   the rhyolitic volcanism of   the region. The fossil flora  includes abundant, poorly preserved impressions of  Sphenophyta that does not permit to assign a precise age, although these forms are common in the Upper Carboniferous-Permian and Triassic of  Argentina.

Palavras-chave : Tambillos Formation; Portezuelo del Cenizo Formation; Sphenophyta.

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