Knickpoints in Martian channels indicate past ocean levels

Duran, Sergio; Coulthard, Tom J.; Baynes, Edwin R.C.

Abstract

On Mars, the presence of extensive networks of sinuous valleys and large channels provides evidence for a wetter and warmer environment where liquid water was more abundant than it is at present. We undertook an analysis of all major channel systems on Mars and detected sharp changes in elevation along the river long profiles associated with steep headwall theatre-like valleys and terraces left downstream by channel incision. These breaks in channel longitudinal slope, headwalls and terraces exhibit a striking resemblance with terrestrial fluvial features, commonly termed 'knickpoints'. On Earth, such knickpoints can be formed by more resistant bedrock or where changes in channel base-level have initiated erosion that migrates upstream (such as tectonic uplift or sea level change). We observed common elevations of Martian knickpoints in eleven separate channel systems draining into the Martian Northern lowlands. Numerical modeling showed that the common elevations of some of these knickpoints were not random. As the knickpoints are spread across the planet, we suggest that these Martian knickpoints were formed in response to a common base level or ocean level rather than local lithology. Thus, they potentially represent a record of past ocean levels and channel activity on Mars.

Citation

Duran, S., Coulthard, T. J., & Baynes, E. R. (2019). Knickpoints in Martian channels indicate past ocean levels. Scientific reports, 9(1), Article 15153. https://doi.org/10.1038/s41598-019-51574-2

• Journal Article Type: Article
• Acceptance Date: Sep 23, 2019
• Online Publication Date: Oct 22, 2019
• Publication Date: Oct 22, 2019
• Deposit Date: Oct 22, 2019
• Publicly Available Date: Oct 23, 2019
• Journal: Scientific reports
• Print ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 1
• Article Number: 15153
• DOI: https://doi.org/10.1038/s41598-019-51574-2
• Keywords: Geomorphology; Hydrology; Inner planets
• Public URL: https://hull-repository.worktribe.com/output/2976581
• Publisher URL: https://www.nature.com/articles/s41598-019-51574-2
• Contract Date: Oct 22, 2019