Brain terrain

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With the superior resolution of cameras on Mars Global Surveyor (MGS) and MRO, we have found the surface of lobate debris aprons, lineated valley fill, and concentric fill have a complex tangle of ridges that resemble the surface of the human brain . Wide ridges are called closed-cell brain terrain, and the less common narrow ridges are called open-cell brain terrain.[1] It is thought that the wide closed-cell terrain still contains a core of ice, that when it eventually disappears the center of the wide ridge collapses to produce the narrow ridges of the open-cell brain terrain. Today it is widely accepted that glacier-like forms, lobate debris aprons, lineated valley fill, and concentric fill are all related in that they have the same surface texture. Glacier-like forms in valleys and cirque-like alcoves may coalesce with others to produce lobate debris aprons. When opposing lobate debris aprons converge, linear valley fill results [2] They probably all contain ice-rich material.

Many of these features are found in the Northern hemisphere in parts of a boundary called the Martian dichotomy. The Martian dichotomy is mostly found between 0 to 70 E longitudes.[3] Near this area are regions that are named from ancient names: Deuteronilus Mensae, Protonilus Mensae, and Nilosyrtis Mensae.

Lobate debris aprons, lineated valley fill, and concentric fill probably have dirt and rock debris covering huge deposits of ice.[4][5][6][7]

  • Coloe Fossae Lineated valley fill, as seen by HiRISE. Scale bar is 500 meters long. Location is Ismenius Lacus quadrangle.

  • Closed-cell brain terrain, as seen by HiRISE under the HiWish program. This type of surface is common on lobate debris aprons, concentric crater fill, and lineated valley fill.

  • Open and closed-cell brain terrain, as seen by HiRISE, under HiWish program.

References

  1. ↑ Levy, J., J. Head, D. Marchant. 2009. Concentric crater fill in Utopia Planitia: History and interaction between glacial ‘‘brain terrain’’ and periglacial mantle processes. Icarus 202, 462–476.
  2. ↑ Souness, C. and B. Hubbard. 2013. An alternative interpretation of late Amazonian ice flow: Protonilus Mensae, Mars. Icarus 225, 495-505.
  3. ↑ Barlow, N. 2008. Mars: An Introduction to its Interior, Surface and Atmosphere. Cambridge University Press. ISBN 978-0-521-85226-5
  4. ↑ Head, J. and D. Marchant. 2006. Evidence for global-scale northern mid-latitude glaciation in the Amazonian period of Mars: Debris-covered glacial and valley glacial deposits in the 30 - 50 N latitude band. Lunar. Planet. Sci. 37. Abstract 1127
  5. ↑ Head, J. and D. Marchant. 2006. Modifications of the walls of a Noachian crater in Northern Arabia Terra (24 E, 39 N) during northern mid-latitude Amazonian glacial epochs on Mars: Nature and evolution of Lobate Debris Aprons and their relationships to lineated valley fill and glacial systems. Lunar. Planet. Sci. 37. Abstract 1128
  6. ↑ Head, J., et al. 2006. Extensive valley glacier deposits in the northern mid-latitudes of Mars: Evidence for the late Amazonian obliquity-driven climate change. Earth Planet. Sci. Lett. 241. 663-671
  7. ↑ Head, J., et al. 2006. Modification if the dichotomy boundary on Mars by Amazonian mid-latitude regional glaciation. Geophys. Res Lett. 33

See also

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