SOTTILE Gonzalo David
congresos y reuniones científicas
Eastern Andean Patagonia (40º-51ºS) vegetation and climate variability during the Holocene related to southern westerlies fluctuations
SOTTILE, G.D.; MARCOS, ALEJANDRA; BAMONTE, F.; ECHEVERRÍA, MARCOS; DE PORRAS, M. E.; TONELLO, M. S; MANCINI, M. V.; BIANCHI, M. M.
Congreso; PAGES 2nd Young Scientist Meeting; 2013
The integration of eastern Andes Patagonian peat, lake and caves records offer the opportunity to get a better understanding of different plant communities response to environmental challenges at different scales. The selected fossil records implied in this study are located between 40-43°S in western (NWP), central (NCP) and northeastern of Patagonia (NEP) and between 49°-51°S in western (SWP) and southcentral (SCP) of Patagonia. Since the early Holocene northern and southern records shows similar patterns, displacing forest and grass steppe communities eastwards and showing high fire activity. This vegetation shifts may have been forced by weaker westerlies allowing humid air masses to reach eastward. During the middle Holocene WNP registered short humid periods inferred by eastern expansion of the forest communities and low fire activity meanwhile in NCP and NEP xeric steppe communities dominate with low fire activity suggesting arid conditions by an intensification of westerly belt. This westerlies behavior is inferred in SWP by the development of dense forest and arid shrubs steppes and low fire activity. Between 3000-2000yrs BP, north and south steppe reconstructions suggest wetter conditions possibly associated to an equatorial displacement and weakening of the westerly belt. Since the 2000 to 500yrs BP there is a similar trend from wetter to arid conditions inferred by northern and southern steppe sequences. After the Medieval Climatic Anomaly (last 500yrs BP) the NEP shows palynological and charcoal evidences of wetter conditions than the previous period meanwhile the SWP presents short periods of wetter conditions inferred also by glaciological records.