Paleolake Inlet Valley Formation: Factors Controlling Which Craters Breached on Early Mars

Abstract

The ancient surface of Mars is dominated by degraded impact craters with reduced or eliminated rim relief. Some degraded craters have an inlet valley, while many remain fluvially isolated. Despite controlling Martian fluvial connectivity, few constraints exist on why some—but not all—degraded craters possess inlets. We compared a suite of properties around degraded Martian craters with and without inlets to ascertain what topographic and hydrologic factors influenced inlet formation. Slope and surface roughness are similar, but topographic inset within the catchment, drainage density, and potential contributing areas diverge for breached and non‐breached craters. We suggest that the importance of basin hydrology‐related factors over topographic factors is the result of the former less frequently surpassing inlet incision thresholds than the latter. We conclude that greater topographic inset (i.e., craters deeper within regional depressions) promoted higher discharge, and that inlet valley formation was ultimately controlled by Mars' crater‐dominated topography.

Remote Sensing and Data Analyses on Planetary Topography

“…From the visual interpretation of ortho-rectified image products, the methodology has evolved to GIS settings [293][294][295], cross-sectional/volumetric analysis of channels and valleys [296][297][298], hydrologic channel routing [299,300], interpretations on alluvial fans and deltas [301,302], and hydrodynamic simulations [303,304]. Volcanic and tectonic analyses of planetary surfaces have traced similar patterns to terrestrial ones and have now introduced techniques based on the integrated use of high-resolution DEMs and numerical/analytical techniques, such as morphological measurements [305,306], finite element methods [307][308][309], viscous/thermodynamic simulations [310,311], and discrete element methods [312,313], which were applied to multiple tectonic/volcanic features on planetary surfaces, such as faults, grabens, wrinkle ridges, calderas, cryovolcanoes, lava tubes, lithospheric interactions, and volcanic slopes.…”

Megaflood Erosion on Mars—How Lava‐Filled Craters Became Mesas (With Insights From Lava Physics, Stream Power, and Rock Mechanics)

“…There is convincing evidence of hundreds of paleolakes on Mars of various ages, many having formed in craters (Cabrol & Grin, 1999, 2010; Goudge et al., 2015). In some instances the paleolakes overflowed and breached the crater rims or other topographic barriers that contained them (Bamber et al., 2022; Coleman et al., 2007; Fassett & Goudge, 2021; Goudge et al., 2019, 2021, 2023). If the resulting breaches formed quickly, megafloods were spawned and dam breach theory can be used to formulate hydrographs for those floods (Coleman, 2013, 2015).…”