Abstract

DANGAVS, Nauris V.  and  PIERRARD, Leonardo R.. Paleolimnology of Laguna del Monte, San Miguel del Monte, Buenos Aires Province. Rev. Asoc. Geol. Argent. [online]. 2013, vol.70, n.1, pp.128-143. ISSN 0004-4822.

It was characterized the physiography, hydrologic regime, typology and origin of this shallow lake. In outcroppings four lithostratigraphic units and two pedostratigraphic were recognized, which span from Early to Late Pleistocene and from Late Holocene to Upper Late Holocene. The oldest one, the Ensenada Formation, makes up the regional substratum, which is covered by the aeolian origin units Buenos Aires, La Postrera III and IV Formations and the Sin Nombre and Puesto Berrondo Geosols. In the lakes infilling sediments are seven litostratigraphic units, five subaqueous and two aeolian. The subaqueous units are ascribed to Luján Formation, La Chumbiada, Lobos, Río Salado and Monte Members, which span from the Late Pleistocene to Late Holocene and the recent Alluvium layer. The lakes aeolian infilling deposits are ascribed to La Postrera I and IV Formation of Late Pleistocene and Upper Late Holocene, respectively. The lake basin deflation started during the "Bonaerense" aeolian episodes, the subsequent alternate humid and dry climatic stages facilitate the lake basin evolution. The dry stages were characterized by deflation, sabkhas, salt precipitation and aeolian deposit accumulation. In the humid stages predominate infilling and pedogenesis. Thus, the subsequent deposits to Ensenada Formation are represented by five dry climatic episodes, which span from the Early Glacial to the Little Ice Age and five humid, with lentic accumulations, extending from La Chumbiada Member to the present Alluvium and the synchronic soils S4, S1 and S0 (lack S2 and S3).

Keywords : Quaternary; Pampa; Lentic environment; Stratigraphy; Paleoclimates.

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