The effect of terrestrial weathering on the magnetic properties of meteorites from the Atacama Desert

Once ordinary chondrites fall on Earth, Fe–Ni minerals and troilite they contain oxidize and transform into iron oxyhydroxides and/or iron oxides, which is expected to modify their magnetic properties. In this study, the effect of long-term terrestrial weathering on the magnetic properties (magnetic susceptibility and hysteresis parameters) of 117 H and L ordinary chondrites from the Atacama Desert (Chile), a region hosting the oldest meteorite collection in the world, was investigated. The measurements revealed a consistent weathering-induced decrease in the saturation magnetization and magnetic susceptibility of both H and L chondrites. The observed trends indicate a faster initial weathering of Fe–Ni minerals compared to troilite, their transformation into mostly paramagnetic iron oxyhydroxides, as well as the formation of magnetite in the later weathering stages.

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