Análisis fitolítico de la Formación Tezanos Pinto (Pleistoceno tardío- Holoceno temprano) en el sector noroeste de su área de distribución en la provincia de Entre Ríos (Argentina)

ERRA GEORGINA ; ZUCOL, ALEJANDRO FABIAN; KRÖHLING DANIELA MARIELA

REVISTA MEXICANA DE CIENCIAS GEOLóGICAS

CENTRO GEOCIENCIAS UNAM

Año: 2011 vol. 28 p. 398 - 412

1026-8774

Loess deposits are the main component of the Late Quaternary sequences of Pampa plains (SouthAmerica). The loess unit of the Last Glacial Maximum at the leeward side of the Pampean aeoliansystem represents primary loess, indicating the expansion of semiarid conditions to the NE ofthat system. The Tezanos Pinto Formation is the typical loessic unit of the late Pleistocene-earlyHolocene of North Pampa, characterized by its considerable spatial continuity. The fi rst result of the phytolith analysis of the Tezanos Pinto Formation at the Northwest area of the Entre Ríos province is presented in this contribution. The analyzed phytolith assemblages show a high homogeneity with several variations that allowed their quantitative differentiation across the sedimentary sections. The presences of grass phytoliths jointly with palm, podostemoid and ciperoid elements allowed to realize this characterization. The association of danthoniod, pooid-festucoid, chloridoid and panicoid grass phytolith types described the presence of a cold temperate to temperate steppe with xeric conditions in the basal levels, with temperate episodes with major moisture principally in their middle and top sections.