Abalos Undae

Abalos Undae on Mars

Abalos Undae is a dune field on Mars in the periphery of the Planum Boreum, the Martian North pole.[1] It is located in the southwest channel that separates the Abalos Colles formation remnant from the main ice cap, and continues all the way to the channel's southern boundary.[1][2] The dunes of the Abalos field may have formed from erosion of Rupes Tenuis (Latin: Thin Cliff), the polar scarp.[1][3] Its name was approved by IAU in 1988.[4] It extends from latitude 82.2° N to 74.94° S and from longitude 283.03° E to 261.4° W. Its origin is located at classical albedo feature with coordinates 72° N, 70° W and has a diameter of 442.74 km.[4]

Location and formation characteristics

The edge of the dark dunes of Abalos Undae shown just below the polar scarp and cap

Enhanced colour images obtained by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter highlight the areas of the dunes where different materials are present.[1] The blue areas indicate the presence of dunes of basaltic origin, while the light-colour areas are probably dust. The pictures are of sufficient resolution to show ripples on the dune surface.[1] The ripples are generated by winds, as are the dunes.[1] The dunes are considered stationary as a unit, with only small ripple movements present.[1]

Similarly to the rest of the dune fields around the periphery of Planum Borealis, the Abalos dune field is considered to consist of lag deposits resulting from the ablation of the sediment found in basal units.[2] The Abalos dune field is considered one of the densest dune fields in the circumpolar region of Mars. Other fields of similar density in the region include the Olympia, Hyperboreae, and Siton Undae.[5][6]

The Abalos dune field consists of transverse dune linear sequences that, overall, form platforms of sand ranging from approximately 10 metres to 200 metres thickness.[5] Abalos Undae, along with Hyperboreae and Siton Undae, is a sand tributary to mostly medium-density sand fields located east of Olympia Undae and extending to the prime meridian of Mars.[5] Image analysis, performed using the method of spectral derivatives, indicates that Abalos Undae, and the rest of the densest dunes fields in the periphery of Planum Borealis, Olympia Undae and Hyperboreae Undae, show the highest pixel density indicating the presence of gypsum.[6] The gypsum of Abalos Undae may be eroding due to scouring action by substrates of bedrock involved in plains formation.[5]

See also

References

  1. 1 2 3 4 5 6 7 Kate Fishbaugh (19 November 2008). "Dunes in Abalos Undae".
  2. 1 2 Niels Hovius, Andrew Lea-Cox, Jens M. Turowski (29 May 2008). "Recent volcano–ice interaction and outburst flooding in a Mars polar cap re-entrant". Icarus (197): 24–38. doi:10.1016/j.icarus.2008.04.020.
  3. ↑ NASA quote: "Today's image location is slightly east of Monday's image. In this image the polar scarp (called Tenuis Rupes) bisects the image.
  4. 1 2 "Abalos Undae". USGS.
  5. 1 2 3 4 K. L. Tanaka, R. K. Hayward. "MARS’ NORTH CIRCUM-POLAR DUNES: DISTRIBUTION, SOURCES, AND MIGRATION HISTORY." (PDF). Planetary Dunes Workshop: A Record of Climate Change (2008).
  6. 1 2 M. Massé, O. Bourgeois , S. Le Mouélic, C. Verpoorter, A. Spiga, L. Le Deit (2012). "Wide distribution and glacial origin of polar gypsum on Mars". Earth and Planetary Science Letters. 317-318: 44–45. doi:10.1016/j.epsl.2011.11.035.
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