Spectral and geological analyses of domes in western Arcadia Planitia, Mars: Evidence for intrusive alkali-rich volcanism and ice-associated surface features

Small-scale domes with circumferential aprons and concentric aureoles in western Arcadia Planitia (34–41°N, 167–179°E) near Tyndall crater were examined using a suite of datasets including CRISM, THEMIS IR, HiRISE, CTX. Previous studies based primarily on photogeologic evidence suggested that these analogous to terrestrial felsic cryptodomes extrusive lava domes. The have also been CRISM visible/near infrared short-wave (VNIR-SWIR) reflectance spectra which indicated the presence ferrous silicate minerals association This study presents further spectral for 1) high-Ca pyroxene glass mixtures with, or possibly without, olivine flanks some domes, 2) 1.3 μm band absorption features consistent an Fe-bearing plagioclase Fe-rich alkali feldspar more limited occurrences at base 3) convexity between 3.4 3.9 associated rocky, light-toned portions top is attributed alkali-rich feldspars. New morphologic observations include pitted cone arcs light-toned, “brain terrain” material pole-facing upper margins which, combination ice-associated outer suggests ice. morphology assortment feldspars they represent continuum from intrusive flat potentially composition although formation viscous mafic magmas not precluded.