Magnetic properties of lunar materials: Meteorites, Luna and Apollo returned samples

We present the first comprehensive study of the magnetic properties of lunar meteorites and compare them with measurements from Apollo and Luna returned samples. 37 unpaired lunar meteorites were studied, while new susceptibility measurements were performed on 88 Luna soil and rock samples, to complement published Luna and Apollo data. New magnetic data were also obtained on 4 Apollo mare basalt samples. Magnetic susceptibility and saturation remanence appear mainly controlled by the amount of metallic iron added by the regolith-forming processes and meteoritic contamination, as shown by a positive correlation with Ni and Ir content, a decrease with depth in regolith core profiles, and a decrease with increasing soil size fraction. The three sources of lunar materials provide coherent range of magnetic properties, although the much larger abundance of anorthositic highland samples in the meteorite collection allows one to better describe the properties of this major lunar lithology. The observed range of saturation remanence implies that mare basalts cannot contribute significantly to the patchy lunar crustal magnetizations, which must be attributed to superficial impact processed feldspathic or mafic lithologies.