Glacial and gully erosion on Mars: A terrestrial perspective

Abstract

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Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues

“…Schon et al (2012) advocates this model based on the correlation between the calculated age of one particular gully they studied and the emplacement time of dust-ice covered mantling deposits. The presence of intimate relationship between glaciers and gullies is further supported by de Haas et al (2018), who show that glacial activity often removes gully deposits (leaving only the crown of the gully-alcoves exposed) but that gullies subsequently rapidly form within the formerly glaciated crater wall (Conway et al, 2018a). The support and caveats of these models are the same as those discussed in the previous section on melting of ground ice.…”

“…2.6 Temporal context (age and activity) Gullies are geologically very young landforms that formed within the last few million years. This is inferred from the conspicuous absence of superposed impact craters on gullies (e.g., Malin and Edgett, 2000), superposition relationships with polygons, dunes and transverse aeolian ridges (e.g., Malin and Edgett, 2000;Reiss et al, 2004), their occurrence in young impact craters that formed within the last few million years (Conway et al, 2018a;de Haas et al, 2018de Haas et al, , 2015bJohnsson et al, 2014) and the presence of secondary craters related to recent crater impacts as marker horizons on gully-lobes (Schon et al, 2009a). Geologically young gully deposits are present in both very young and very old host craters (< 1 Ma to > 1 Ga), and their size is unrelated to host-crater age (de Haas et al, 2018;Grotzinger et al, 2013).…”

“…Documenting the temporal evolution of gully systems was already noted as one of the main outstanding questions and avenues for advancement regarding the understanding of martian gullies by Dickson and Head (2009), yet very few papers have addressed this topic since then. De Haas et al (2018) show that after their formation in fresh craters, gullies may go through repeated sequences of (1) LDM deposition and reactivation and (2) glacier formation and gully removal (Conway et al, 2018a), followed by the formation of new gully systems. In general, gullies in host craters that are younger than a few Ma have not been affected by LDM or glaciation (type 1), gullies in host craters of a few Ma to a few tens of Ma have been affected by LDM but not by glaciation (type 2), and gullies in host craters of more than a few tens of Ma have been affected by both LDM and glaciation (type 3).…”

Initiation and Flow Conditions of Contemporary Flows in Martian Gullies

“…This material is usually interpreted as a latitude‐dependent mantle located on sloping terrain formed from airfall of ice nucleated on dust (e.g., Head et al, ; Milliken et al, ; Mustard et al, ) but may also have been (partly) reworked by glaciation and be predominantly glacial in origin (cf. Conway et al, ). One of our study sites, gully 9 (Figure b), solely cuts into this pasted‐on terrain and therefore probably largely consists of fine‐grained materials, while gullies 26 and 69 (Figures a and c) have source areas consisting of both bedrock and pasted‐on terrain and may thus potentially transport larger clasts.…”

Martian gullies and their Earth analogues: introduction

“…This Special Publication contains a cross-section of the latest work on Martian gullies. The subjects presented at the workshop, but not encapsulated by the papers within this Special Publication, include: the implications of global climate model results for the formation of Martian gullies, which have been seminal in establishing the obliquity paradigm (Costard et al 2002) and bolstering the CO 2 hypothesis (Pilorget & Forget 2016); numerical modelling of the flows that form Martian gullies (Pelletier et al 2008;Mangeney et al 2010); the role of dry processes, including wind and dust, in gully formation and modification (Treiman 2003;De Haas et al 2015); the spectral identification of volatiles and minerals at active gully sites (Vincendon 2015); the reporting of controversial equatorial Martian gullies (McEwen et al 2018); and the link between the generation of recurring slope lineae and gullies and gullies as a landform within a paraglacial time series (Jawin et al 2018;Conway et al 2018a). The breadth of the topics covered in this Special Publication, at the workshop and in the wider literature attest to a continuing interest in these familiar, yet enigmatic, landforms.…”