CRISM-Based High Spatial Resolution Thermal Inertia Mapping Along Curiosity's Traverses in Gale Crater

Thermal inertia is a key summary property describing the thermophysical characteristics of geologic materials. Orbital estimates of thermal inertia are especially useful in conjunction with rover-based observations to provide additional constraints on material properties and to interpret the broader region surrounding the traverse. We have developed an approach to estimate apparent thermal inertias (ATI) from observations from the Mars Reconnaissance Orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at a much higher spatial resolution than is available from any other orbital data set. We apply this method to along-track oversampled scene FRT00021C92 over Gale Crater within Glen Torridon, where the Curiosity rover has traversed; the retrieved values are then analyzed along with remote sensing and in-situ observations by Curiosity to characterize surface properties in and around Glen Torridon. CRISM-based ATI estimates of basaltic sand fields indicate a correlation between higher ATI values and the abundance of large (up to 3 mm in size) grains on the crests and flanks of large ripples. On the Vera Rubin ridge, ATI estimates are used to identify a west-to-east increase in the abundance of rock fragments within unconsolidated surface cover. On the Greenheugh pediment, an unmixing approach is used to identify a thin layer of wind-blown sand sourced from the nearby Sands of Forvie. Finally, within Glen Torridon, a north-to-south increase in the mean and width of the ATI distribution is identified as a consequence of increased bench-like bedrock exposures.

Automated summary

Thermal inertia is a key property for describing the thermophysical characteristics of geologic materials. This study presents an approach to estimate apparent thermal inertias (ATI) from observations of the Mars Reconnaissance Orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which provides higher spatial resolution than other orbital data sets. The ATI estimates are used to analyze and characterize surface properties in different regions on Mars, such as the abundance of large grains in basaltic sand fields, the increase in rock fragments on the Vera Rubin ridge, the presence of wind-blown sand on the Greenheugh pediment, and the exposure of bench-like bedrock in Glen Torridon.