CORDOBA francisco elizalde
congresos y reuniones científicas
High resolution climate and environmental reconstruction from lake sediments in Lake Comedero, NW Argentina: preliminary results.
Congreso; 20th Congress of the International Union for Quaternary Research (INQUA); 2019
Institución organizadora:
International Union for Quaternary Research
The Andes forelands of NW Argentina cover the climatic transition zone between the South American Monsoon System and the Pacific Westerlies, which are the two main metrological precipitation systems of southern South America. Therefore, this region is sensitive to shifts in climatic transition zones due to climate changes and a key region for past climate reconstructions. However, only sparse information on past climate variability is available for this area. Here we present a more than 10 m long sediment record from Laguna Comedero (24º 06? 54.7? S - 65º 29? 7.2? W, 2100 m asl, 5 m deep), located in the Provincial Park Lagunas de Yala, NW Argentina. Preliminary results reveal a clear change in sedimentation from detrital brown layers in the lower part of the core to an alternation of gray clastic and black organic-rich intervals with abundant plant debris in the upper 3.5 m. Below this sediment depth we find low values for TOC, C/N and S in combination with high Si, Ti and K values, revealing no variation of detrital sediments and low ammounts of organic matter. However, TOC, C/N and S values stongly increase above 3.5 m. TOC values in the upper 3.5 m ranges from 0.1 to 20.5%, while organic C/N atomic ratio reaches values up to 17, suggesting a substantial contribution of allochthonous organic matter in some layers. These intervals also show low values in elements indicative of detrital input (e.g. Si, Ti) and high Mn/Fe that indicate periods of reducing conditions at the lake bottom. Changes recorded in Laguna Comedero sediments reveal that the deposition in the lake varied strongly. Further analysis needs to be done and a detailed chronology is still required to reveal the link between this sediment record and a climate and environmental reconstruction for this region.