Loading...
Glacial and gully erosion on Mars: A terrestrial perspective
Conway, SJ Butcher, FE de Haas, T Deijns, AA Davis, JM
Conway, SJ
Butcher, FE
de Haas, T
Deijns, AA
Davis, JM
Citations
Altmetric:
Advisors
Editors
Other Contributors
Affiliation
EPub Date
Issue Date
24/05/2018
Submitted Date
2018-08-17
Subject Terms
Mars
Martian gullies
Viscous flow features
Glacier-like forms
Liquid water
Martian gullies
Viscous flow features
Glacier-like forms
Liquid water
Collections
Research Projects
Organizational Units
Journal Issue
Other Titles
Abstract
The mid- to high latitudes of Mars host assemblages of landforms consistent with a receding glacial landscape on Earth. These landforms are postulated to have formed >5 Ma under a different climate regime when Mars' orbital obliquity was on average 10° higher than today. Here, we investigate the spatiotemporal relationship between gullies and glacial landforms, both common in the mid-latitudes. Gullies are kilometre-scale landforms with a source alcove, transportation channel, and depositional apron. The glacial landforms comprise (1) extant viscous flow features (VFF) that extend from the base of crater walls into the interior of crater floors and are widely interpreted as debris-covered glaciers containing extant ice, and (2) landforms such as arcuate ridges at the base of crater walls that have been interpreted as relicts of more recent, less extensive glacial advances focussed on crater walls. We measure headwall retreat associated with glacial landforms and date their host-craters to constrain minimum headwall retreat rates. We record headwall retreat rates up to ~102 m My−1 for the youngest suite of glacial landforms, equivalent to erosion rates of wet-based glaciers on Earth and to headwall retreat rates associated with martian bedrock gully systems. We find extensive evidence for a single erosional episode dating 5–10 Ma, which postdates emplacement of the majority of VFF but seems to predate formation of the gullies. We propose that the wet-based glacial episode was associated with glaciation focussed on the crater walls rather than melting of the glacial ice deposits on the crater floors (VFF). This is consistent with our observations of crater wall morphologies, including the presence of arcuate ridges consistent with terrestrial glaciotectonic features that require liquid water to form, textural alteration of the eroded bedrock surface consistent with ice-segregation and frost-shattering, and the presence of downslope pasted-on terrain, tentatively interpreted here as glacial till deposits sourced from glacial erosion of the crater wall. The pasted-on terrain is usually interpreted as a thicker, latitude-dependant mantle located on sloping terrain formed from airfall of ice nucleated on dust, but we suggest that it has been reworked by glaciation and is predominantly glacial in origin. Although our results cannot substantiate that gullies are produced by meltwater, the discovery of this wet glacial event does provide evidence for widespread meltwater generation in Mars' recent history.
Citation
Susan J. Conway, Frances E.G. Butcher, Tjalling de Haas, Axel A.J. Deijns, Peter M. Grindrod, Joel M. Davis, Glacial and gully erosion on Mars: A terrestrial perspective, Geomorphology, Volume 318, 2018, Pages 26-57, ISSN 0169-555X, https://doi.org/10.1016/j.geomorph.2018.05.019. (http://www.sciencedirect.com/science/article/pii/S0169555X18302125)
Publisher
Journal
Research Unit
PubMed ID
PubMed Central ID
Embedded videos
Type
Journal Article
Item Description
The attached document is the authors’ final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it. It is covered by a CC-BY-NC-ND user license.
NHM Repository
NHM Repository
Series/Report no.
ISSN
0169-555X
EISSN
ISBN
ISMN
GovDoc
Test Link
License
closedAccess