The high-resolution stereo camera on ESA’s
Mars Express imaged the Charitum Montes region of the Red Planet on 18 June, near
to Gale crater and the Argyre basin featured in our October and November image
releases. The brighter features, giving the image an ethereal winter-like feel
in the colour images, are surfaces covered with seasonal carbon dioxide frost.
Charitum Montes are a large group of rugged
mountains extending over almost 1000 km and bounding the southernmost rim of
the Argyre impact basin. They can be seen from Earth through larger telescope
and were named by Eugène Michel Antoniadi (1870–1944) in his 1929 work La Planète Mars.
Annotated image
The images in this release all show the
region’s old and highly-sculpted terrain, pockmarked with many large craters,
all of which have been substantially filled in. The whole region is dusted with
brighter carbon dioxide frost.
Perspective view
Numerous smaller ‘pedestal craters’ can also
be seen in the 3D and 2D images. These are impact craters where the ejecta have
formed a higher relief above the surroundings. One striking example is visible
on the smooth plain to the lower right in the annotated image (Box A).
Topographic view
The ejecta surrounding pedestal craters form
erosion-resistant layers, meaning that the immediate vicinity around the crater
erodes more slowly than the surrounding terrain. The resistant ejecta layer is
largely untouched, forming the pedestal.
Perspective view
Another well-preserved example of a pedestal
feature surrounding an impact crater can be seen within the large, old and
heavily-degraded crater on the lower-left side of the annotated image (Box B).
In the centre of the 2D images and dominating the perspective images is a
crater some 50 km wide filled with thick sedimentary deposits.
These deposits appear to have been introduced
through one of several breaches in the northern crater rim (Box C in the
annotated image). Dendritic channels appear to emanate from a completely
filled-in crater in this region (Box D), at the periphery of the large crater’s
northern edge.
Within the large crater, near to where the
breach (C) in the crater wall occurred, though unconnected to this event, we
can also see a small dune field (Box E). A region of significant interest to scientists lies within the large crater towards the top left
of the first image (Box F). This crater shows a diverse range of filling
material, with layers of varying colour and texture.
Charitum Montes in context
The uppermost layer appears to be bright and
smooth, taking on the appearance of a relatively thin blanket with some impact
craters. This layer interfaces with the underlying darker layer via some very
sharply defined edges, possibly as a result of erosion. The underlying darker
material has a much rougher and mottled appearance, and planetary geologists
are still studying possible causes. To the left of the crater interior, another
layer of sediments clearly sets itself apart from the underlying strata, partly
forming flat-topped structures (Box G).
3D view
The complexity and diversity of some areas in
this winter wonderland would doubtless give Father Christmas a hard time in
finding somewhere safe to land, but images like these are giving planetary
geologists yet another fascinating region of the Red Planet to study.
For
further information visit: http://www.esa.int/esaCP/SEMH7W2ABAH_index_2.html
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