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  • Writer's pictureM Akbar Hussain

More on the enigmatic dark streaks on Mars

Back to the topic of the mysterious dark streaks on Mars after a long hiatus.

No one truly knows the true nature or the mechanism of formation of these dark slope streaks on Mars which are scattered along the slopes on nearly the entire surface of Mars. The jury is still out on whether these are dry avalanches, or suggest evidence of current or recent fluid activity. Many researchers support the dry nature of these streaks, i.e. caused by avalanches of fine, dry material tumbling down the slopes causing further avalanches along its way, resulting in fanning out of the streak, and exposing darker soil hidden beneath. It is seemingly true for many streaks with very smooth edges and flow patterns, and supported by the spectral analysis of the streaks using CRISM data (Amador 2016) revealing dry nature of their makeup. But many streaks look nothing like random dry sandy avalanches. Amador et al noted that some of the streaks contain signature of hydration as transient spectral absorption in the near IR-spectra, signifying fluid origins in some cases. This may mean that not all streaks are formed by the same mechanism, and in fact these dark streaks possibly belong to two distinct and entirely unrelated physical phenomena; dry sandy avalanches, and periodic fluid flows from underground sources, possibly aquifers.

Here are two pictures (above) of dark streaks on the slopes of the southern flanks of Olympus Mons from Google Earth (derived from HiRISE imagery). Three very distinct features are obvious in these images which raise high possibility of their being of fluid origin.

1. Sinuous and wavy pattern of flow, and curving around obstacles.

2. Emerging from more or less the same level from just underneath the crust along the upper edge of cliffs over a very long distance.

3. Following the tracks of dried sinuous flow patterns over the slopes of Olympus Mons above the cliffs.

In fact, such streaks closely resemble the mud flows from active mud volcanoes on Earth, notably the mud volcanoes of Hingol and Lasbela regions of Pakistan, that led us to propose that the dark streaks on Mars similar to the ones in these pictures may be active mud flows (Hussain 2021), indicating not only active mud volcanism on Mars, but presence of liquid water very close to the Martian surface, which may have huge implications in the search of life on Mars.


  1. Amador E. S., Mushkin A., Gillespie A., Spectral Characteristics of Dark Slope Streaks on Mars. 47th Lunar and Planetary Science Conference 2016

  2. Hussain M. A., Hussain M. M., Mud volcanism on Mars: Investigating Possible Surface Liquid Water Activity on Mars using Evidence from Terrestrial Mud Volcano Analogues. Mars Society Convention 2021.

  3. Google Earth resources

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