¹Melissa De Andrade Nunes,¹Ricardo I. F. Trindade,¹João Pedro Rodriguez Pinto,²Alvaro P. Crósta,³Gabriel G. Silva,⁴Ludovic Ferrière,¹Camila R. Sales,¹Giovanna M. Tosi
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70155]
¹Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo, Sao Paulo, Brazil
²Institute of Geosciences, University of Campinas, Campinas, Brazil
³Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
⁴Natural History Museum Abu Dhabi, Abu Dhabi, United Arab Emirates
Published by arrangement with John Wiley & Sons

Geraisites are a newly recognized class of tektite from Brazil. They occur as centimeter-sized, elongated to subspherical bodies scattered across surface gravel and shallow subsurface layers within a ~90-km-long strewn field extending between the municipalities of São João do Paraíso and Curral de Dentro, near the border between the states of Minas Gerais and Bahia. This study presents a rock magnetic characterization of geraisites, aimed at understanding their magnetic mineralogy and remanent magnetization. The samples exhibit weak bulk magnetization dominated by a paramagnetic contribution, consistent with typical tektite compositions. In addition, rock magnetic analyses indicate the presence of a ferromagnetic fraction, as evidenced by demagnetization curves and hysteresis behavior. Lowrie–Fuller test and isothermal remanent magnetization decomposition indicate a dominant low-coercivity component consistent with nanoscale magnetite grains in the single-domain to pseudo-single-domain range. In some samples, the remanence behavior suggests overprinting by transient high-field processes, such as lightning-induced remanent magnetization. Furthermore, geraisites show a distinct relationship between magnetic susceptibility and iron content compared to other splash-form tektites, reflecting their relatively enhanced ferromagnetic contribution. Overall, these results provide new insights into the magnetic properties of geraisites and their comparison with other tektite populations.