Thermophysical Properties of Martian Fluvial Sinuous Ridges: Inferences on “Inverted Channel” Induration Agent

Abstract

AbstractIn denuded landscapes, terrestrial inverted fluvial landforms are preferentially preserved due to their greater resistance to erosion from clast armoring, lava infilling, or cementation. These induration agents have differing material properties that should influence the thermal response of the surface. Using thermal inertia derived from 2001 Mars Odyssey Thermal Emission Imaging System (THEMIS) data, we find that the thermophysical contrast for 20 large “inverted channels” on Mars is comparable or elevated in comparison to nearby well‐indurated materials. The fluvial sinuous ridge (FSR) thermal signature, together with regional geology and morphology attributes, leads us to disfavor clast armoring as an induration agent for most Martian FSRs. The available evidence is consistent with cementation as the most likely induration agent for FSRs, although lava infilling is a plausible explanation especially for instances of nearby volcanic edifices. FSR cementation, probably by near‐surface solute‐rich groundwater, extends aqueous processes beyond the period of widespread fluvial activity. Future work on the temporal response of the surfaces of inverted channels has the potential to further test the inferred induration mechanism and potentially constrain the grain size distribution.