Granular flows at recurring slope lineae on Mars indicate a limited role for liquid water

Colin M. Dundas, Alfred S. McEwen, Matthew Chojnacki, Moses P. Milazzo, Shane Byrne, Jim N. McElwaine, Anna Urso

Research output: Contribution to journalReview articlepeer-review

104 Scopus citations


Recent liquid water flow on Mars has been proposed based on geomorphological features, such as gullies. Recurring slope lineae - seasonal flows that are darker than their surroundings - are candidate locations for seeping liquid water on Mars today, but their formation mechanism remains unclear. Topographical analysis shows that the terminal slopes of recurring slope lineae match the stopping angle for granular flows of cohesionless sand in active Martian aeolian dunes. In Eos Chasma, linea lengths vary widely and are longer where there are more extensive angle-of-repose slopes, inconsistent with models for water sources. These observations suggest that recurring slope lineae are granular flows. The preference for warm seasons and the detection of hydrated salts are consistent with some role for water in their initiation. However, liquid water volumes may be small or zero, alleviating planetary protection concerns about habitable environments.

Original languageEnglish (US)
Pages (from-to)903-907
Number of pages5
JournalNature Geoscience
Issue number12
StatePublished - Dec 1 2017

ASJC Scopus subject areas

  • General Earth and Planetary Sciences


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