CONICET | Buscador de Institutos y Recursos Humanos

Development conditions of wet-meadows (mallines)include water availability and topographic/geological settings that allow thefine sediments accumulation and slow water circulation through them. InArgentina, wet-meadows are present in Patagonian, Andean and Pampean Rangesregions; in latter they have been less studied. This work analyzes thedistribution and morphometry of wet-meadows, and their sedimentological record,in a granitic area of Cerro Áspero batholith, with the purpose of contribute tounderstanding of their dynamics and paleoenvironmental-paleoclimaticconditions. Through of satellite images the wet-meadowswere recognized and morphologically characterized. The field work includedgeophysical surveys in a active wet-meadowsand descriptions and sampling of exposed sedimentological profiles. Granulometry (particle laser counter) and organic matter content (losson ignition) determinations were made. The wet-meadows are located between 890 and 1130 m a.s.l., especially inporphyritic biotite granite unit, in axis valleys/small "pampas"positions, and they have elongated or irregular forms (average 190 m long and47 m wide). In according with geophysical information thickness of finesediments would locally exceed 10 m. V1 Profile is formed by a very homegeneoussandy-silt sequence, grayish to black color, very bioturbated. It?s interpretedas a low energy environment deposit, associated with wet-meadow axis. V2Profile is formed by similar deposits, but with gravelly-sand lenticular acrossit. It sequence is linked to margin positions of wet-meadow, where thesegravelly-sand levels would be generated by sporadic fluid flows, of differentenergy and short trajectory. Until the radiocarbon age results are received, theanalyzed deposits could be assigned to Hypsithermal period, which wascharacterized by accumulation of fine sediments in marshy environments.