Magnetization records of terrestrial weathering in the Sericho pallasite
Ji-In Jung, Sophia Gaal, Sonia M. Tikoo, Ethan Lopes, Jonathan Mells, Dale H. Burns, Robert G. Hatfield
MAPS, Version of Record online: 06 August 2026
“Paleomagnetic investigations of pallasites are important for understanding the dynamo histories of their parent bodies and the formation mechanisms of these meteorites themselves. To understand the temporal evolution of pallasite parent-body dynamos, additional paleomagnetic studies of new meteorites are needed. However, such efforts require a thorough understanding of magnetic carriers and recording properties of pallasites to ensure that any observed remanence reflects primary magnetic records. Here, we investigate olivine grains in the main group Sericho pallasite to evaluate their suitability for paleomagnetic studies. Electron microscopy, combined with rock magnetic analyses, reveals colloidal, euhedral magnetite grains hosted within iron oxide veins (likely goethite) formed during post-fall aqueous alteration within our Sericho sample. All results indicate that secondary mineral phases dominate the remanence, precluding reliable recovery of primary parent-body magnetic fields. Our study presents a cautionary tale about how different samples of the same meteorite can experience heterogeneous degrees of weathering, ranging from effectively pristine to so altered that paleomagnetic studies probing parent body processes cannot be conducted. As such, meteorites must be carefully scrutinized on an individual-sample basis before paleomagnetic studies to ensure high-fidelity results.”
