Application of the pseudo-Thellier technique to a paleomagnetic record of 18 000 years from lake El Trebol, Patagonia, Argentina

GOGORZA, C.S.G.; TORCIDA, S.; IRURZUN, M.A.; CHAPARRO, M.A.E.; SINITO, A.M.

GEOFíSICA INTERNACIONAL

Geofísica UNAM

Lugar: Mexico; Año: 2008 vol. 47 p. 319 - 327

0016-7169

The pseudo-Thellier technique was applied to obtain relative paleointensity determinations using a sediment core from Lake El Trébol (Patagonia, Argentina). Measurements of intensity of Natural Remanent Magnetization left (NRMleft) versus intensity of Anhysteric Remanent Magnetization gained (ARMgain) at the same peak were carried out on a set of samples after AF demagnetization. Two versions of a jackknife resampling scheme were used to obtain error estimates of the paleointensity. Pseudo-Thellier paleointensity records were compared with the authors’ previous results where the remanent magnetization at 20mT (NRM20mT) had been normalized using the anhysteric remanent magnetization at 20mT (ARM20mT), the saturation of the isothermal remanent magnetization at 20mT (SIRM20mT) and the low field magnetic susceptibility (k) (Gogorza et al., 2006). Any technique that meets the criteria of magnetic uniformity will produce reliable results, but a robust estimation of the slope of the regression should be preferred, because it minimizes the effect of outliers.