Accumulation Rate Variability Analysis of High-Altitude Cushion Peatlands as Sentinels of Holocene Environmental Changes in the Central Andes (Northwestern Argentina)

KARSTEN SCHITECK; SEBASTIAN KOCK; LILIANA C. LUPO; FRANK SCHÄBITZ

Conferencia; 4th Southern Deserts Conference; 2014

Laboratorio de Paleoecologia Humana. Universidad Nacional de Cuyo

Located at the crossroads between tropical and extra-tropical precipitation regimes, thesouthern Central Andes are a key area for paleoclimatic studies. Our investigations showthat high-altitude cushion peatlands (bofedales) are extremely well-suited for multi-proxypaleoecological studies. The strengths of these geoarchives are their comparability over climatic gradients, their high accumulation rates, and the high quality of their peat deposits which can be precisely 14C dated. In the high Andes of northwestern Argentina,peat cores were retrieved from high-altitude cushion peatlands. The peat sequences, up to8.50 m long, provide a high-resolution, continuous Holocene climate reconstruction inthe central Andes for the first time. Prominent climatic oscillations were detected, which arealso detectable in high-resolution paleoclimate records from extra-tropical latitudes. The results confirm that Northern Hemisphere climate oscillations had a significant impact on the summer monsoon activity of the tropical/subtropical Southern Hemisphere.Temperature fluctuations further had an impact on the redox conditions of the peatlands.Fluctuating redox conditions result in accumulation or mobilization processes of heavyand semi-metals, which can serve as a climatesensitive proxy and should be further explored.