Core correlation and preliminary paleosecular variation results from lacustrine sediments of Laguna Potrok Aike, Patagonia, Argentina

PALERMO, P.; IRURZUN M. A.; GOGORZA, C. S.; SINITO A. M.; GEBHARDT,C.; ZOLITSCHKA, BERND

San Pablo

Congreso; 4ta. Reunión Bienal de LATINMAG; 2015

LATINMAG

In this work, two parallel cores were studied in order investigate the changes in the direction of the Earth magnetic field. Particularly, the work was made in sediments from Laguna Potrok Aike, a maar lake located in Southern Patagonia, Argentina. The cores (5022-1A and 5022-1B) were obtained during the drilling campaign PASADO in 2008. The separation between the cores is 8 m. Magnetic susceptibility (k) at low and high frequency in a total of 340 samples were measured and analyzed to achieve the correlation between the cores. The result k logs show a strong correlation, which allows the combination into one composite record for the site. The direction (inclination and declination) of the stable (o primary) remanent magnetization was obtained by demagnetizing the samples in an alternating field in growing steps. The inclination oscillates mainly between -36 and -88 ° for 5022-1A and between -56 and -81 ° for 5022-1B. Only a few samples are out of these ranges. The age-depth model indicates the studied samples span a period of 4800 yrs. An increasing trend is observed in both cores for the first 30 cm (360 yrs). Similar results were observed in other cores from Laguna Potrok Aike and other lakes in the area and they were also confirmed by geomagnetic models.