INVESTIGADORES
GOGORZA Claudia Susana
congresos y reuniones científicas
Título:
Paleosecular Variations Recorded by Sediments from Laguna Potrok Aike (Patagonia, Argentina): Preliminary Studies
Autor/es:
GOGORZA, C.S.G.; IRURZUN, M.A.; SINITO, A.M.; OLHENDORF,C.; ZOLITSCHKA, B
Lugar:
Foz do Iguazu
Reunión:
Congreso; American Geophysical Union (AGU) - Meeting of the Americas; 2010
Institución organizadora:
American Geophysical Union (AGU)
Resumen:
Paleomagnetic, rock-magnetic and sedimentological studies were performed on a 16 m long piston core from the 100 m deep centre of Laguna Potrok Aike. This maar lake is located in the Province of Santa Cruz, Southern Patagonia (Argentina). Roughly 80 km north of the Strait of Magellan, it is situated in the Pali Aike Volcanic Field (51° 58S, 70° 23W) (Zolitschka et al., 2006). Measurements of intensity and directions of Natural Remanent Magnetization (NRM), magnetic susceptibility, isothermal remanent magnetization, saturation isothermal remanent magnetization (SIRM), back field and anhysteretic remanent magnetization at 100 mT (ARM100mT) were performed and several associated parameters calculated (ARM100mT/k and SIRM/ ARM100mT). Also, as a first estimate of relative magnetic grain-size variations, the median destructive field of the NRM (MDFNRM), was determined. Stability of the NRM was investigated by alternating-field demagnetization (AF). Most of the samples show no systematic change in the direction of their remanent magnetization during AF demagnetization; few of them have a viscous magnetization, which could easily be removed by AF demagnetization at about 10 mT. Rock magnetic properties document that main carriers of magnetisation are ferrimagnetic minerals, predominantly pseudo single domain magnetite. The NRM as well as declination and inclination logs of the characteristic remanent magnetization for all samples as function of calibrated ages were obtained. Comparison between inclination and declination records of Laguna Potrok Aike and results obtained in earlier studies carried out at lakes Escondido (Gogorza et al., 2002), Moreno (Gogorza et al., 2000) and El Trébol (Irurzun et al., 2008), were performed.
