Abstract

CERVANTES-SOLANO, Miguel et al. On the reliability of some transitional paleomagnetic records along the Transmexican Volcanic Belt. Bol. Soc. Geol. Mex [online]. 2024, vol.76, n.3.  Epub Dec 31, 2024. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2024v76n3a140224.

The Earth's magnetic field experiences variations in both its essentially dipolar configuration and absolute intensity. Paleomagnetic records have shown that these variations can be so extreme that the field has reversed its polarity on multiple occasions in the geological past. Moreover, the geomagnetic field occasionally moves away from its most stable dipole position for relatively short periods, heading in the opposite direction without reaching total geomagnetic reversal. In this context, paleomagnetic studies carried out recently in the Trans Mexican Volcanic Belt have provided some new evidence about several potential geomagnetic excursions that occurred during the last million years. However, some of these results are controversial since sites with the same associated age yielded contradictory paleomagnetic directions. These differences have been attributed both to the precision in age determination and to methodological aspects during sampling, which makes their interpretation difficult from a geomagnetic point of view. Here we report, a detailed rock-magnetic, aeromagnetic and paleomagnetic study on nine independent cooling units belonging to the Michoacan Guanajuato Volcanic Field (Trans-Mexican Volcanic Belt) where these lava units have provided some contradictory results reported in previous studies.

Keywords : paleomagnetism; geomagnetic excursion; Michoacán-Guanajuato volcanic field.

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