[meteorite-list] Mars Express Images: Hummocky and Shallow Maunder Crater

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 19 Oct 2007 09:40:33 -0700 (PDT)
Message-ID: <200710191640.JAA28942_at_zagami.jpl.nasa.gov>

http://www.esa.int/SPECIALS/Mars_Express/SEMOHJAMS7F_0.html

Hummocky and shallow Maunder crater
Mars Express
European Space Agency
16 October 2007

The High Resolution Stereo Camera (HRSC) on ESA's Mars Express orbiter
has obtained pictures of the Noachis Terra region on Mars, in
particular, the striking Maunder crater.
 
The images were taken in orbits 2412 and 2467 on 29 November and 14
December 2005 respectively, with a ground resolution of approximately 15
metres per pixel.
 

[Noachis Terra context map]

Maunder crater lies at 50 degrees South and 2 degrees East, approximately in the
center of Noachis Terra. The sun illuminates the scene from the
north-east (top left in the image).

The impact crater, named after the british astronomer Edward W. Maunder
(1851-1928), is located halfway between Argyre Planitia and Hellas
Planitia on the southern Highlands of Mars.

 
[A perspective view of Maunder Crater]

With a diameter of 90 kilometres and a depth of barely 900 metres, the
crater is not one of the largest impact craters on Mars at present, but
it used to be much deeper. It has since been filled partially with large
amounts of material.

The west of the crater experienced a major slope failure, during which a
large landslide transported loose material eastward, to the inner parts
of the crater. The edges of the crater rim that collapsed exhibit
gullies which might be associated with the mass transport of the material.


[Maunder Crater, perspective view]

The transition zone from the western rim of the crater to the rather
smooth crater floor on the eastern edge shows hummocky terrain. Such
terrain exhibits small, irregularly-shaped hills and valleys. The
hummocky terrain in the Maunder crater was formed by deposition of
landslide debris.

In the east, the crater floor is bounded by a trough, approximately 700
metres deep. The trough may be associated with a landslide on the
western edge of the crater. Some gullies can be seen on the upper edge
of the trough which is possible evidence for water seepage.

 
[Maunder Crater, Noachis Terra]
 
The small, 500 to 2500-metre long, dark features on the crater floor are
eye-catching. These features are called Barchan dunes, one of the most
abundant dune forms in arid environments. Dunes of this kind are also
found on Earth, for example in the West-African Namib desert.

The colour scenes have been derived from the three HRSC-colour channels
and the nadir channels. The perspective views have been calculated from
the digital terrain model derived from the HRSC stereo channels. The
anaglyph image was calculated from the nadir channels and two stereo
channels, stereoscopic glasses are required for viewing. The 3-D
(anaglyph) picture has been put together from several individual 3-D
images of different scenes, enhancing the view over larger areas.

 
[Maunder Crater, Noachis Terra]
Received on Fri 19 Oct 2007 12:40:33 PM PDT