HiRISE Updates (2011 May 11)

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HiRISE Updates (2011 May 11)

Post by bystander » Thu May 12, 2011 10:07 pm

HiRISE Science Team wrote:

Bedform Changes in Aureum Chaos (ESP_021906_1765)

Aureum Chaos, located in the eastern part of Valles Marineris, is a complex area with light-toned material. Pits in this region are visible in MOC (Mars Orbital Camera) data. Does layering in the pits relate to the light-toned material at all?

This region is southwest of Aram Chaos, and like the name "chaos" suggests, the terrain is characterized by randomly oriented, large-scale mesas and knobs that are heavily eroded and dominate the area. (You might also see the phrase "chaotic terrain" used to describe such areas.)

The OMEGA experiment on Mars Express discovered clay minerals (phyllosilicates) in a variety places in Aureum Chaos. Since these minerals require water to form, it's possible large amounts were once here. The removal of that water is one of the ways the terrain was formed.

HiRISE has imaged this area before to track changes: PSP_004448_1765 and ESP_013269_1765.
HiRISE Science Team wrote:

Promethei Planum (ESP_021915_1005)

These area near the Southern ice cap, has an interesting formation. It looks slightly rectangular; perhaps it's a large section of glacial ice. A study of this formation may reveal new knowledge about erosion, and ice formation on Mars!

This area is seasonally covered with a layer of ice. Promethei Planum lies at approximately 76 degrees South and 105 degrees East.
HiRISE Science Team wrote:

Potential Mars Landing Site Near Mounds Associated with Crater Rim (ESP_021919_2135)

This observation shows large mounds that may represent hydrothermal diapirism in a lacustrine (lake) setting, possibly involving fluid movement from great depth. "Diapirism" is a process where a more mobile (and deformable) material is forced up onto overlying material, hence the mounds. An easy point of reference for this process is something most people have seen: a lava lamp.

One of the justifications for this observation is to assess landing/roving hazards and morphology. Additionally, HiRISE has a stereo pair and an anaglyph that helps determine morphology and mineralogy of the mounds and the suitability of a future landing ellipse. This observation also underscores how landing sites are chosen: a safe place to land and explore that is also scientifically compelling.
Patrick Russell wrote:

Possible Inverted Topography Landscape with Clay Minerals (ESP_022077_2000)

This site, near Mawrth Vallis is intriguing for several reasons. First of all, there are lots of little knobs and plateaus that may expose layers of sedimentary rock. As on Earth, sedimentary rock on Mars is expected to hold clues to the conditions under which it formed - clues to the past environment and climate.

Second, many of the larger, darker plateaus appear fairly round. Typically Mars' surface is pock-marked with round depressions of impact craters. However, these round areas are raised up relative to the surroundings. This may be an example of inverted topography, in which an impact depression may have become filled with material which was, or became, harder than the surrounding terrain, and thus was more resistant to later erosion. Example materials may be solidified molten rock created during the impact event, or sediments that hardened due to alteration by water ponding within the crater.

Third, clay minerals, called phyllosilicates, have been detected here by other spacecraft instruments. Clays are exciting because they indicate there was most likely water around here long ago. Determining which layers and knobs contain the clays, and how widespread they are, will help scientists determine how much water existed here and for how long.

This site has been deemed so interesting that it is under consideration for a visit by a future landed rover.
Credit: NASA/JPL/University of Arizona

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Re: HiRISE Updates (2011 May 11)

Post by owlice » Thu May 12, 2011 11:11 pm

Someone lost an ear on Mars!
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A closed mouth gathers no foot.