They mark the action of the wind on the Martian dunes, generating huge waves of sand up to 10 meters high
Waves of blue sand that appear to sprinkle the Martian landscape are actually transverse wind ridges (TARs), intermediate-sized structures consisting of very coarse-particled sand. According to NASA, the colors of these structures suggest ongoing erosion processes and allow us to appreciate the action of the wind on the red planet.
An image obtained by NASA’s Mars Reconnaissance Orbiter shows an incredible landscape of Mars, which again surprises us: in this case, mysterious bluish shapes that look like waves are really the manifestation of a wind phenomenon. It is gigantic sand dunes, which form larger crests due to the action of the wind and rise up to 10 meters above their usual height. They are located near the center of the Gamboa crater, in the northern hemisphere of Mars.
According to a publication by the US space agency, the different colors shown in the image also mark the dynamics of the martian wind processes. Apparently, the faster moving structures expel, when affected by the wind, the darker sand particles. As a consequence of this, their brightness increases and this affects the tonality they show.
Shaped by the wind
The largest and brightest formations, which can be seen in a relatively parallel configuration, are the wind ridges or TAR. The way in which they actively move under the force of the wind and their brighter hue are characteristics that can indicate how the wind blew when they were formed and allow us to learn more about their structure, which differs significantly from the dunes that can be seen in the earth.
According to a study carried out on these strange formations and published in the journal Icarus, the differences in the distribution of the size of the sand grains can explain the variants in the shapes of these “dunes & rdquor; wind-shaped Martian rocks, which scientists also call “wind beds” or “wind ranges”, depending on the form they present. In some cases, the untamed force of the wind creates sinuous ridges and individual domes of sand.
According to the researchers, Mars hosts a wide variety of “wind bed” forms, reflecting the dominance of wind in mid-latitude and equatorial surface processes. They also provide important clues to understanding the Martian sediment transport throughout the planet, linked to other phenomena observed on Mars and still surprise scientists.
unique shapes
Although the landscape forms on Earth and Mars share many similarities, some Martian structures are relatively uncommon on our planet, leading to ambiguities in our understanding of their formation and inconsistencies in their description. you are strange undulating dunes of coarse sand are one of those examples: although on Earth phenomena of this type are observed in deserts or areas near the seas, the Martian typology is unique due to the way in which the wind modifies the shapes, the characteristics of the sand and the chromatic effects created.
It seems that researchers still have a long way to go to fully understand the role of these structures on Mars. In principle, few Martian wind data are available to fully understand its interactions with the surface and landscape. In addition, our understanding of wind transport on Mars and the importance of dust in the development of the forms of these “dune” it seems incomplete. To gain a more detailed understanding, the researchers recommend performing specific wind observations by future orbital and surface missions.
Reference
Ripples, megaripples, and TARs, Oh, My! Recommendations regarding Mars aeolian bedform terminology. Mackenzie Day and James R. Zimbelman. Icarus (2021). DOI:https://doi.org/10.1016/j.icarus.2021.114647