Análisis fitolíticos de depósitos eólicos parcialmente edafizados (Pleistoceno tardío ? Holoceno) en la región de Tandilla (provincia de Buenos Aires, Argentina).

M. M. COLOBIG; PATTERER N.I.; A. F. ZUCOL; G. MARTÍNEZ; E. PASSEGGI

La Plata (BA)

Congreso; Congreso Argentino de Cuaternario y Geomofología ? XII Congresso da Associacao Brasilerira do Cuaternario ? II Reunión sobre el Cuaternario de América del Sur; 2009

Universidad Nacional de La Plata

The phytolith assemblages of aeolian depositional sequences with partially edaphic conditions (Late Pleistocene- Holocene) from Tandilia region (Buenos Aires Province, Argentina) were analyzed. Siliceous remains were obtained by densimetric separation (with sodium polytungstate as heavy liquid) of the cleaned samples (with elimination of carbonates, organic matter and dispersion of clastic elements). The multivariate analysis of phytolith assemblagescomposition allows to differ two different groups across the studied profile. The lower component was dominated by morphotypes with danthoniod affinity, the presence of arecoid morphotypes, and a scarce presence of chloridoid, stipoid and panicoid elements. The upper component of the sequence is characterized by a smaller abundance of danthoniod elements and an important increase of phytoliths with stipoid and chloridoid affinity in the mean levels that decreases towards the top of the profile where the relative frequency of panicoid phytoliths increases. In this unit different ciperoid morphotypes were also observed. This analysis allows to interpret that from the parental deposits, the development of this sequence was accompanied in its initiated stages by a vegetation conformed by stipoid and chloridoid elements mainly, with a scarce water availability. Later would have been replaced by a panicoid dominated community, which added to the evidence of presence of sedges allows to suppose a superior hydric availability.