A Reconnaissance Study of Central Cores From Laguna Melincué (Pampean Plains, Argentina)

IRURZUN, M.A.; L. SANCHEZ BETTUCCI; J.A. SÁNCHEZ CABEZA; ACHAGA, R.; AVTO GOGUITCHAICHVILI; A.C. RUIZ FERNÁNDEZ; CLAUDIA GOGORZA; JUAN MORALES; A. M. SINITO

Juriquilla

Congreso; 5° Reunión Bienal de la Asociación Latinoamericana de Paleomagnetismo y Geomagnetismo (LATINMAG); 2017

LatinMag - UNAM

We present the first magnetic, lithological and dating results on three center sites from Laguna Melincué to contribute to identifying paleoclimatic proxies and present preliminary paleomagnetic results for the site. Laguna Melincué has been previously studied from different approaches, mainly to understand hydrological and climatic variations, but more multidisciplinary studies are needed to understand its complex hydrological situation. From every site three cores were extracted and the longest one was selected to make 210Pb measurements. On the three cores, measurements of magnetic susceptibility and lithology description were made. The susceptibility logs indicate that in the sediments were recorded the variations of magnetic minerals concentration during the same period and a correlation between the dated core and the others could be done. The lithology description indicates granulometric variations that fluctuate between fine sands and clayed slit sectors. The presence of layers with high organic matter content was also identified. Variations in 210Pb were studied to date the sediments. This method provides very good dating results for the last century. In this case the first 36 cm recorded changes during the last 116 ± 4 years. It is interesting the study of this period since it makes possible a high resolution environmental analysis that possibly leads to some conclusion about the relationship between floods and agricultural exploitation in the area. Therefore, a comparison with a shore core previously studied is restricted to the period 1900?2016 AD.