Abstract

DIAZ, Ulises Demian et al. Main features of the geomagnetic field strength in Mexico during the Plio-Pleistocene. Bol. Soc. Geol. Mex [online]. 2024, vol.76, n.3.  Epub Dec 31, 2024. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2024v76n3a220424.

We report new absolute paleointensity determinations obtained from independent lava flows emplaced during the Pliocene and distributed along the Tepic-Zacoalco Rift (Western Trans-Mexican Volcanic Belt). In addition, we carried out a compilation and analyses of previous paleointensity studies carried out in Mexico, covering age intervals of the last 5 million years. The average value of the virtual dipole moment obtained for the last million years (10 × 1022 Am2), is higher than that observed in other locations worldwide. On the other hand, for the periodfrom 3 to 5 million years, the average value of the dipole moment is 6 × 1022 Am2, which apparently suggests a gradual increase in intensity at least at regional scale, during the last million years. A significant decrease in intensity was detected for a presumably transitional lava flow. These results agree with previous studies carried out in the surrounding areas, reporting a notably low paleointensity value associated with a rather unstable geomagnetic regime.

Keywords : Paleointensity; Tepic-Zacoalco Rift; Plio-Plesitocene.

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