PRELIMINARY PALEOMAGNETIC RESULTS FROM LAGUNA MELINCUÉ (LA PAMPA, ARGENTINA)

ACHAGA, ROMINA V.; IRURZUN, M.A.; AVTO GOGUITCHAICHVILI; C. S. G. GOGORZA; MORALES, J.; A. M. SINITO; DANIEL LOPONTE

San Pablo

Congreso; IV Reunión Bienal de la Asociación Latinoamericana de Geomagnetismo y Paleomagnetismo- LATINMAG; 2015

Asociación Latinoamericana de Geomagnetismo y Paleomagnetismo

We present preliminary results of rock magnetic and paleomagnetic studies on a short sediment core (LMe, 74 cm) collected from Laguna Melincué (33° 41? 27.8??S, 61° 31? 36.5??W). The core was manually collected from the shore of the Laguna Melincué using a plastic tube during October of 2014. It shows centimeter-scale lamination and frequent textural variations. Measurements of intensity and directions of natural remanent magnetization (NRM), volumetric magnetic susceptibility (k), isothermal remanent magnetization (IRM), saturation isothermal remanent magnetization (SIRM), back field experiments and anhysteric remanent magnetization at 100 mT (ARM) were performed. As a first estimate of magnetic grain-size variations, the ratios ARM/SIRM and ARM/k were calculated. The stability of the NRM was analyzed by alternating field demagnetization. Rock magnetic analysis (Sratio and Bcr), hysteresis curves and the temperature-dependence of magnetic susceptibility (kT) suggest that the magnetic mineralogical content is  dominated by pseudo single-domain (titano) magnetite and/or maghemite.