Estudios paleoambientales en lagos volcánicos en la Región Volcánica de Pali Aike, sur de Patagonia (Argentina): palinología

Frank Schäbitz,María Mancini,Nora Maidana,Michael Wille,Christian Ohlendorf,Hugo Corbella,Christoph Mayr,Andrea Lücke,Marta Paez,Gerhard Schleser,Torsten Haberzettl,Aldo Prieto,Bernd Zolitschka,Flavia Quintana

doi:10.22179/revmacn.5.61

Abstract

Palaeoenvironmental studies of crater lakes in the Pali Aike Volcanic Field, southern Patagonia (Argentina): palynology . Sedimentary records from crater lakes are of major scientific interest because they provide continuous high-resolution paleoclimatic and paleoenvironmental archives. For the first time a limnogeological and palynological survey of crater lakes was performed in the Pali Aike Volcanic Field (52°S, southeastern Santa Cruz, Argentina). Studied lakes of the Patagonian steppe are mostly shallow and consist of old and already sediment-filled volcanic structures or of deflation pans. However, bathymetric measurements revealed two deep crater lakes: Laguna Azul (50 m) and Laguna Potrok Aike (100 m) which may serve as archives for paleoecological studies. Although modern pollen spectra are related with vegetational and the precipitation gradients from the Andes to Atlantic coast, the modern pollen spectra of both lakes revealed the change of plants communities in each geomorphological unit. The first approach between modern pollen data and fossil material from the fine-grained sediments of both lakes we are able to interpret environmental and climatic variations during the last 2,000 years as well as human influence for the last two centuries.

Highlights

Sedimentary records from crater lakes are of major scientific interest because they provide continuous high-resolution paleaclimatic and paleoenvironmental archives
For the first time a limno.r.eolo.e.ical and n. al.moloe..ieal survey of crater lakes was oerformed in tho Pali Aike Volctinic Field
El proyecto SALSA (South Argentinean Lake Sediment Archives and Modelling) tiene el propdsito de contribuir a esta problematica mediante estudios interdisciplinarios de datos cuantitativosmiiltiples proxies en registros lacustres de alta resolucidn en el Campo Volcanico de Pali Aike (PAVF) (Fig. I)

Summary

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F. gmcillimo ; m*rg alcanaa valores anuales de 244 mm; sin embargo durante 10s meses de verano la temperatura alcanza 6" C e incluso valores bajo O" C Weischet, 1996). Aproximadamen en el sector doride se localiza la isohicta anual 250-300 mm, en esta formaci6nse diferencianu estepa hfimeda al oeste y una mas x6rica en centro-este (Roig et al, 1985; Le6n et al, 199 donde se localiza el P A W (Fig. 1).En Areas m hiimedas, con desayies poco profundos, que atr viesan la estepa de Festuca gracillima, se ext' den 10spastizalesdeEpallescens (St.Yves)Par. En las imagenes satelitales se obser dedor de cien lagunas en el PAW. En el analisis do polen firsil ias las dos lagunas mas profnndas y con agua perma- snmas polinicas alcanzaron 10s500 granos, exclunente, Laguna Azul y Laguna Potrok Aike En la elaboraciitn de mapas batimetricos se interpolaron un total de 7.428y 3.494 mediciones de profundidad para las Lagunas Potrok Aike y Azul, respectivamente. PoIen y vegetacibn actual a escala regional, En 10sespectros polinicos (grupo 1,Fig. 2,) 10s

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Findings

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