Microwave paleointensity analysis of historic lavas from Paricutín volcano, Mexico

Abstract

We report a microwave paleointensity study of historic lavas from Paricutin volcano, erupted during the period between 1943 and 1948. Most samples are characterized by uni-vectorial orthogonal plots. Rock-magnetic and microscopy studies indicate pseudo-single-domain titanomagnetites as the remanence carriers. The microwave paleointensity technique was applied to selected samples using both Kono and Ueno (1977) and Coe et al. (1978) variants of the Thellier method. The samples yielded technically high quality paleointensity results, though show high within-flow dispersion and are significantly different from the expected value of 45mT. This is also seen in results using the Thellier method (Urrutia-Fucugauchi et al., 2004). Explanations for this behaviour are explored, with reference to other historic lava studies. The technically high quality of the results suggest there is no criteria that can distinguish between correct and erroneous paleointensity data.

Keywords

• Paleomagnetism
• paleointensity
• microwave technique