Comprehensive paleomagnetic study of a succession of Holocene olivine-basalt flow: Xitle Volcano (Mexico) revisited

A detailed paleomagnetic study of a young Late Holocene olivine-basalt flow from the Xitle volcano in the southern Basin of Mexico was completed to evaluate the consistency and reliability of the record derived from fresh well-preserved and exposed lava flows. One-hundred oriented standard paleomagnetic cores corresponding to 10 different lava effusion episodes were collected from unit-flow V. Thermomagnetic analyses show that bulk magnetic properties and remanence is carried in most cases by Ti-poor titanomagnetite, presumably resulting from oxy-exsolution processes during the initial flow cooling. Unblocking temperature and coercivity suggests pseudo-single domain magnetic grains for these (titano)magnetites. Thermal and alternating field demagneti-zations show well-defined univectorial magnetizations. Most sites present a mean direction with small angular dispersion around the dipolar direction for central Mexico. The overall mean direction (N = 10, Dec = 1.1◦, Inc = 34.1◦, k = 531 and α95 = 2.1◦) is characterized by small angular dispersion and inclination close to the dipolar value for the locality. Anisotropy of magnetic susceptibility lineation agrees with the geologically-inferred flow direction. Various samples from the 10 lava flows were selected for Thellier paleointensity experiments be-cause of their stable remanent magnetization and relatively low within-site dispersion. According to reliability parameters, the obtained paleointensities are of reasonably good quality. Nine mean paleointensities range be-tween 48.6 and 73.9 µT. The overall mean paleointensity of 59.9–7.7 µT is higher than the present-day field o