Pasquon, Kelly; Gargani, Julien; Nachon, Marion; Conway, Susan J.; Massé, Marion; Jouannic, Gwenaël; Balme, Matthew R.; Costard, François and Vincendon, Mathieu
(2019).
| DOI (Digital Object Identifier) Link: | https://doi.org/10.1144/SP467.13 |
|---|---|
| Google Scholar: | Look up in Google Scholar |
Abstract
We describe and compare the morphology and activity of two types of gullies with different orientations collocated on the Kaiser dune field in the southern hemisphere of Mars: large apron gullies and linear dune gullies. The activity of large apron gullies follows an annual cycle: (i) material collapse into the alcove (mid-autumn/late winter) as CO2 condenses; (ii) remobilization by mass flows (late winter); and (iii) continuous appearance of hundreds of ‘digitate flows’ on the fan (autumn/winter). We find that large apron gullies could form in hundreds of Martian years. In contrast, linear dune gullies are active briefly in late winter, when the CO2 frost disappears. Their activity is characterized by the extension of channels, the creation of pits and the darkening of the surface. Linear dune gullies are likely to form within one to tens of Martian years. We infer that insolation, which influences the depth to ground ice and the amount of volatile deposited, may be the factor differentiating large apron gullies and linear dune gullies. Sediment transport by CO2 sublimation is a good candidate for the activity observed in all of these features. However, linear gullies could also be formed by brine release when the temperature rises abruptly after the removal of the CO2 ice.
| Item Type: | Book Section |
|---|---|
| Copyright Holders: | 2019 The Geological Society of London |
| ISBN: | 1-78620-362-6, 978-1-78620-362-5 |
| ISSN: | 0305-8719 |
| Academic Unit/School: | Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences Faculty of Science, Technology, Engineering and Mathematics (STEM) |
| Item ID: | 62172 |
| Depositing User: | ORO Import |
| Date Deposited: | 26 Jun 2019 08:59 |
| Last Modified: | 26 Jun 2019 09:14 |
| URI: | http://oro.open.ac.uk/id/eprint/62172 |
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