Mars mud volcanoes in color: A new approach to the study of subsurface sediment mobilization

Abstract

Mud volcanism has been proposed to explain the formation of morphologically diverse edifices across the surface of Mars. Previous global compositional analysis of surface features on Mars, such as pitted cones and knobs, interpreted as mud volcanoes using Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) targeted data revealed consistent water hydration signatures associated with these landforms (Dapremont and Wray, 2021b). However, no definitive identifications of specific minerals known to comprise mud volcanism materials on Earth (e.g., phyllosilicates, carbonates, sulfates) were identified. Here, we take advantage of an alternative methodology involving a quantitative color band ratio technique using blue-green (BG), red (RED), and infrared (IR) reflectance data sourced from the High Resolution Imaging Science Experiment (HiRISE) camera to determine if any additional mineralogical information about proposed Martian mud volcanoes could be acquired. Across Mars in the three distinct study regions of Valles Marineris, Terra Sirenum, and Arabia Terra, proposed mud materials consistently plot with ferric laboratory and Mars surface reference minerals. In Terra Sirenum, HiRISE color data point clusters acquired from mounds attributed to mud volcanism plot overtop the Fe-smectite reference mineral nontronite. We show that HiRISE color data can be used as a complementary mineralogical investigation tool applied to the study of surface materials on Mars and demonstrate the value of HiRISE color ratios for comparative planetology.