CIFICEN   24414
CENTRO DE INVESTIGACIONES EN FISICA E INGENIERIA DEL CENTRO DE LA PROVINCIA DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A reconnaissance paleomagnetic and paleoclimatic investigation from Laguna Melincué (Argentina)
Autor/es:
ACHAGA, ROMINA; GOGICHAISHVILI, AVTO; LOPONTE, D; IRURZUN, M A; ANA MARÍA SINITO; CLAUDIA GOGORZA; MORALES, JUAN
Lugar:
Puerto Vallarta
Reunión:
Congreso; Unión Geofísica Mexicana, Reunión Anual 2016; 2016
Institución organizadora:
Unión Geofísica Mexicana
Resumen:
We report preliminary results of a multiproxy analysis including paleomagnetic and rockmagnetic studies of two short sediment cores collected from Laguna Melincué (33° 41? 27.8??S, 61° 31? 36.5??W). Measurements of intensity and directions of natural remanent magnetization (NRM), magnetic susceptibility (k), isothermal remanent magnetization (IRM), saturation isothermal remanent magnetization (SIRM), back field (Br) and anhysteretic remanent magnetization at 100 mT (ARM) were performed and several associated parameters calculated (ARM/k, SIRM/ARM and SIRM/ARM). Besides, as a first estimate of relative magnetic grainsize variations, the median destructive field of the NRM (MDFNRM) was determined. The stability of the NRM was analyzed by alternating field demagnetization. Rock magnetic analyses suggest that the well preserved magnetic mineralogy is dominated by pseudo single domain (titano) magnetite and/or maghemite. The changes in magnetic grain size and concentration of magnetic parameters, although of reconnaissance character, suggest environmental variations and changes at the lake level consistent with historical reports.A stable, primary remanent magnetization was retrieved for most of studied samples. The welldefined changes in magnetic parameters (directional and non directional data) indicate the potential of this lake for paleomagnetic studies. The paleodirectional record obtained for the Laguna Melincué agrees quite well with Cals3k.3 model and mores studies will be necessary to reach conclusive results.