[meteorite-list] Mars Express Image: Evidence of Flooding at Mangala Valles

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Jun 10 16:38:11 2004
Message-ID: <200406102037.NAA06616_at_zagami.jpl.nasa.gov>

http://www.esa.int/export/SPECIALS/Mars_Express/SEM4SS2VQUD_0.html

Evidence of flooding at Mangala Valles
European Space Agency
Mars Express

Colour image of Mangala Valles

9 June 2004

These images of fluvial surface features at Mangala Valles on Mars were
obtained by the High Resolution Stereo Camera (HRSC) on board the ESA
Mars Express spacecraft.

The HRSC has imaged structures several times which
are related to fluvial events in the past on Mars.

The region seen here is situated on the Valles
south-western Tharsis bulge and shows the mouth of
the Mangala Valles and Minio Vallis outflow
channels.

The source of the outflow channel is related to the Mangala Fossa, a
fissure running east-west for several hundred kilometres.

One theory about its formation is related to a process known on Earth
as "dyke emplacement".


[Anaglyph image of Mangala Valles]

This is when hot molten rock finds
its way to the surface through a
3D image of Mangala fissure, releasing large amounts of
Valleswater by the melting of subsurface
ice.

It is still unclear for how long and to what extent water, mud or even
ice masses and wind have carved the channel here.

This theory on its formation has several analogues on Earth. Events
like the one proposed for Mangala Valles occur on Earth, for example in
Iceland, where volcanic activity causes episodic releases of water from
subsurface reservoirs, causing catastrophic floods.


Along the channel troughs, areas with
so-called "chaotic terrain" features favour
the idea of the existence of subsurface ice.

[Black and white view of Mangala Valles]

The small-scale chaotic terrain is
characterised by isolated blocks of surface
material which have been randomly arranged during the release of
subsurface water and subsequent collapse of the surface.

Huge areas of chaotic terrain can be found near the source areas of the
outflow channels around Chryse Planitia, such as Kasei, Maja and Ares
Valles.

Beside the large outflow channels, a variety of smaller "dendritic"
valley networks with a number of tributary valleys can be seen near the
main channels. This indicates possible precipitation.


[Mangala Valles]

Perspective view of Mangala Valles

The images were taken during orbit 299 with a resolution of 28 metres
per pixel. The image centre is located at 209? E longitude and 5? S
latitude. For practical use on the internet, the images have been
reduced in resolution.

The red/cyan 3D anaglyph image was created using the stereo- and nadir
channels of the HRSC. The perspective view was calculated from the
digital terrain model derived from the stereo and colour information of
the image data.


The 3D images require stereoscopic glasses to view.
Received on Thu 10 Jun 2004 04:37:49 PM PDT