From Orbit to Outcrop: A Multiscale Integration of CRISM and CheMin Mineralogical Datasets at Gale Crater

Orbital spectroscopy and rover-based X-ray diffraction characterise Mars’s mineralogy at scales differing by six orders of magnitude. However, it remains untested whether orbital data can capture site-specific mineralogical information along a rover traverse. We compare CRISM infrared spectroscopy with CheMin X-ray diffraction at 41 co-located targets along the Curiosity traverse in Gale Crater, reduced by overlapping footprints to 29 independent observations. CheMin group abundances were reconstructed from per-phase Rietveld tables, including clay minerals omitted by crystalline-only compilations. Accounting for per-phase diffraction uncertainties, the dominant mineral group is secure at only 17 sites, with no site dominated by sulfate, carbonate or iron oxide. Seventeen official CRISM spectral parameters were extracted from matching 3 × 3 windows. CRISM returns no detection at all at 78% of sites, and only one of its nine positive detections matches the CheMin-dominant group. Mafic silicates and carbonates are not detected, and no testable group shows a significant relationship with CheMin abundance. The exception is D2200, the 2.2 µm Al–OH parameter, which correlates with CheMin phyllosilicate abundance (r=+0.476, p=0.0019). The classifier returns no call at those same sites, so thresholding discards information the parameter retains. Under the dust and spatial-support conditions of this traverse, orbital classification carries limited site-specific information. This work provides a replicable framework for testing that limit at future landing sites.