Fig. 2: BSE-SEM characterization of ferromagnetic minerals in CE6 soils.
From: Magnetic signatures and origins of ferromagnetic minerals in Chang’e-6 lunar farside soils
a-d Representative backscattered electron scanning electron microscopy (BSE-SEM) images of ferromagnetic minerals in basaltic clast (a); basaltic impact melt (b); agglutinate (c); and glassy agglutinate (d). Insets show magnified details from regions indicated by the dashed yellow boxes. e Glassy agglutinate with abundant spherical and irregular metallic iron (Ir) grains associated with troilite (Tro). f, g Micron-sized metallic iron particles (f) and Fe-Ni alloy (kamacite, Kam) crystals (g) within agglutinates. h Troilite veins associated with taenite (Tae) assemblages in an agglutinate particle. i Enlarged detail of panel h showing troilite-taenite intergrowth. j SEM-based energy dispersive X-ray spectroscopy (SEM-EDXS) spectra from regions (dashed red circles in panels a-g and i) confirming compositions of metallic iron or Fe-Ni alloys. k Grain-size distribution of metallic iron particles in CE6 soils, indicating their potential superparamagnetic (SP), single-domain (SD), single-vortex (SV), or multidomain (MD) behaviors (boundaries adapted from ref. 41). Basaltic materials contain rare, nickel-poor iron grains, whereas agglutinates and glassy materials have abundant iron particles with elevated, variable nickel contents. Additional high-resolution SEM images and SEM-EDXS compositional maps are provided in supplementary Figs. 4–13.
