In-situ investigation of periodic bedrock ridges in the Glen Torridon area with the MSL Curiosity rover, Gale crater, Mars
Abstract
The occurrence of sets of regularly spaced, linear ridges at numerous locations on the surface of Mars has been recognized for two decades via high spatial resolution orbiter images. Many of these landforms have been interpreted as inactive, possibly indurated aeolian bedforms. An alternative proposed by Montgomery et al. (2012, doi:10.1029/2011JE003970) is that some of these ridges are erosional 'periodic bedrock ridges' carved into bedrock by wind and elongated transverse to the dominant wind direction. Although the erosional interpretation for some of these ridges is compelling, the mechanism and process by which periodic bedrock ridges form on Mars remains uncertain, in part, because analogs on Earth are rare.
This study focuses on a 2.5 km2 field of linear, parallel northeast-southwest trending ridges that occur within clay-bearing strata of the Glen Torridon trough on lower north Aeolis Mons within Gale crater. As measured in HiRISE orbiter images and digital terrain models, ridge length varies from a few meters to several hundred meters, ridge height ranges from <1 m to several meters, and wavelengths of ~20 m are typical. Ridge orientation is consistently discordant to the strike of sedimentary bedding. Curiosity image observations show that the bedrock comprising the ridges is predominantly finely laminated mudstone or fine-grained sandstone that has eroded to cm-scale pebbles at the surface. These mudstones and sandstones are interpreted to record a continuation of lacustrine deposition seen throughout the Murray formation. Although origins as lithified aeolian bedforms and erosional landforms were both previously proposed to explain these ridges, this study's analysis supports an interpretation that these are erosional periodic bedrock ridges. We are currently using the Glen Torridon ridges to gain further insights into the depositional context and erosional history of this interval of Aeolis Mons stratigraphy, and to advance understanding of the processes by which periodic bedrock ridges form on Mars.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P33B..02S
- Keywords:
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- 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 6225 Mars;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 5470 Surface materials and properties;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS