Compositional zonation in carbonatite complexes along the Kudu Lineament, Namibia, from EMIT spaceborne hyperspectral imagery

Recently launched spaceborne hyperspectral sensors such as PRISMA and EnMAP have advanced geological remote sensing by enabling regional mapping of compositional variations previously detectable only with airborne data. Geological applications of the Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer, a NASA-developed sensor mounted on the International Space Station (ISS), remain comparatively underexplored, particularly for magmatic systems such as carbonatites. We test whether EMIT at 60 m pixel size can resolve regional-scale mineralogical zonation in the Dicker Willem and Twyfelskupje carbonatite complexes along the Kudu Lineament in Namibia. Using wavelength maps that target 2320-2350 nm and 850-1000 nm wavelength ranges, supported by tailored band ratios, we evaluate spatial and spectral variation in carbonate and Fe 3+ -oxide mineralogy. At Dicker Willem, carbonate-related absorption feature shifts indicate an outward trend from Mg-rich to progressively Ca- and Fe-enriched compositions, and co-vary with a centre-to-edge change in Fe-oxide wavelength positions, consistent with increasing crystallinity towards the centre. Twyfelskupje shows an inverse carbonate trend and weak or incoherent Fe-oxide patterns, suggesting a different crystallisation or alteration history. REE-related absorptions are not resolved, likely due to detection limits, 60 m pixel size, and masking by Fe-bearing minerals. Our findings demonstrate that EMIT spaceborne hyperspectral data can support early-stage reconnaissance of well-exposed, regional-scale carbonatite bodies. • EMIT data enable mapping of regional-scale compositional zonation in carbonatite complexes • Carbonate bands shift Mg to Ca/Fe at Dicker Willem; inverse trend at Twyfelskupje • Fe 3+ -oxide wavelengths map a centre-to-edge crystallinity gradient at Dicker Willem • REE absorptions remain undetectable at 60 m due to detection limit and pixel size • Wavelength maps and band ratios support regional mineral mapping and geological reconnaissance