Preliminary rock magnetic and paleomagnetic studies on sediment cores from laguna La Barrancosa, Argentina

IRURZUN, M.A.; CLAUDIA GOGORZA; EQUIPO OPTATIVA 2016; EQUIPO OPTATIVA 2015

Puerto Vallarta

Congreso; Reunión Anual de la Unión Geofísica Mexicana (UGM 2016).; 2016

Unión Geofísica Mexicana

A set of sediment cores fromLaguna La Barrancosa is studied. The lake is located in the pampean region,Pcia. Buenos Aires, Argentina. The cores were extracted from several sites inthe lake from the shore until the center during 2015 and 2016. Measurements ofmagnetic susceptibility (k), natural remanent magnetization (NRM), anhystereticremanent magnetization (ARM), isothermal remanent magnetization (IRM) andvariations of k with temperature were performed. Associated parameters werealso calculated and inclination (I) and declination (D) were estimated. Theconcentration of magnetic minerals, the magnetic mineralogy and their grainsize were analyzed. The cores lengths are between 25and 65 cm. Previous studies suggest a sedimentation rate of around 1mm/yrs,indicating a maximum extension in time of 650 yrs before present (yrs BP).Concentration parameters allow a correlation of the cores with more correlationtie lines between the cores located in the center of the lake. The core locatedin the shore is also correlated but a hiatus were found around 9 cm, indicatinga low stand of the lake level and a dry environment in the catchment area.