Valley Networks and the Record of Glaciation on Ancient Mars

Abstract

The lack of evidence for large‐scale glacial landscapes on Mars has led to the belief that ancient glaciations had to be frozen to the ground. Here we propose that the fingerprints of Martian wet‐based glaciation should be the remnants of the ice sheet drainage system instead of landforms generally associated with terrestrial ice sheets. We use the terrestrial glacial hydrology framework to interrogate how the Martian surface gravity affects glacial hydrology, ice sliding, and glacial erosion. Taking as reference the ancient southern circumpolar ice sheet that deposited the Dorsa Argentea formation, we compare the theoretical behavior of identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and erosion, on Mars the lower gravity favors the formation of efficient subglacial drainage. The apparent lack of large‐scale glacial fingerprints on Mars, such as drumlins or lineations, is to be expected.

Ice on Noachian and Hesperian Mars: Atmospheric, surface, and subsurface processes

“…The third possibility involves the role of surface gravity in setting the dominant mode of glacial drainage. Even if water accumulated under a late Noachian icy highlands ice sheet, the development of high efficiency drainage channels under ice could prevent significant glacial sliding from developing on Mars in comparison to Earth, producing a geological record that would differ from that characteristic of Quaternary glaciation (Grau Galofre et al, 2022). The third hypothesis is also consistent with the lack of sliding recorded in the DAF.…”

The Geochemical and Mineralogical Signature of Glaciovolcanism Near Þórisjökull, Iceland, and Its Implications for Glaciovolcanism on Mars

“…Water ice is currently present on Mars at the polar ice caps and in high-latitude permafrost (Byrne, 2009;Clifford et al, 2000;Feldman et al, 2004). The distribution of candidate glaciovolcanic landforms on Mars (Figure 2), in addition to other features identified from orbital imaging associated with glaciation at high-and mid-latitudes such as eskers (e.g., Butcher et al, 2016Butcher et al, , 2017Grau Galofre et al, 2022;Souness & Hubbard, 2012), suggests that the distribution of water ice deposits has varied across Mars with time, likely driven by Mars' large changes in obliquity (Clifford et al, 2000;Jakosky et al, 1995;Levrard et al, 2004). Liquid water is not stable at Mars' current atmospheric pressure.…”

Global Spatial Distribution of Hack's Law Exponent on Mars Consistent With Early Arid Climate

“…This has led to many debates about VN's formation processes and early Mars climatic conditions. For example, it may have been that the early climate of Mars was only episodically warm and wet created by brief and strong volcanic activity and associated outgassing of greenhouse gasses and aerosols (Halevy & Head, 2014); or that VNs were formed by groundwater sapping associated with magma intrusion and hydrothermal activities, thus not requiring continuous warm and wet conditions (Gulick, 1998); VNs could also be created during short‐lived episodes of top‐down melting of thick cold‐based ice on the equatorial highlands (Fastook & Head, 2015; Forget et al., 2013; Wordsworth, 2016; Wordsworth et al., 2013) or localized basal melting and erosion by subglacial flows (e.g., Buffo et al., 2022; Grau Galofre et al., 2020, 2022). Scientists are still debating which climatic scenario is correct and whether runoff not involving rainfall can create the observed VNs (e.g., Baker et al., 2015; Ehlmann et al., 2011; Ramirez et al., 2020; Turbet & Forget, 2019).…”