[meteorite-list] The Floodwaters of Mars (Mars Express)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 6 Jun 2013 10:02:27 -0700 (PDT)
Message-ID: <201306061702.r56H2R96009473_at_zagami.jpl.nasa.gov>

http://www.esa.int/Our_Activities/Space_Science/Mars_Express/The_floodwaters_of_Mars

The floodwaters of Mars
European Spsace Agency
6 June 2013

[Image]
Dramatic flood events carved this impressive channel system on
Mars covering 1.55 million square kilometres, shown here in a
stunning new mosaic from ESA's Mars Express.

The mosaic, which features the spectacular Kasei Valles, comprises
67 images taken with the spacecraft's high-resolution stereo
camera and is released during the week of the 10th anniversary of
the spacecraft's launch to the Red Planet.

[Image]
Kasei Valles in context

Kasei Valles is one of the largest outflow channel systems on Mars
- from source to sink, it extends some 3000 km and descends by 3
km in altitude. The scene covered in the mosaic spans 987 km
north-south (19-36??N) and 1550 km east-west (280-310??E).

The channel originates beyond the southern edge of this image near
Valles Marineris, and empties into the vast plains of Chryse
Planitia to the east (right).

[Image]
Kasei Valles topography

Kasei Valles splits into two main branches that hug a broad island
of fractured terrain - Sacra Mensa - rising 2 km above the
channels that swerve around it. While weaker materials succumbed
to the erosive power of the fast-flowing water, this hardier
outcrop has stood the test of time.

Slightly further downstream, the flood waters did their best to
erase the 100 km-wide Sharonov crater, crumpling its southern rim.
Around Sharonov, many small streamlined islands form teardrop
shapes rising from the riverbed, carved as water swept around
these natural obstacles.

The region between Sacra Mensa and Sharonov is seen in close-up
detail in the perspective view below, looking downstream from the
northern flank of Kasai Valles.

Zooming into the valley floor reveals small craters with bright
dust "tails" seemingly flowing in the opposite direction to the
movement of water. In fact, these craters were formed by impacts
that took place after the catastrophic flooding, their delicate
tails created by winds blowing in a westwards direction "up" valley.

Their raised rims influence wind flow over the crater such that
the dust immediately "behind" the crater remains undisturbed in
comparison to the surrounding, exposed, plains.

[Image]
Perspective view of Kasei Valles

Kasei Valles has likely seen floods of many different sizes,
brought about by the changing tectonic and volcanic activity in
the nearby Tharsis region over 3 billion years ago.

The landscape was pulled apart under the strain of these forces,
groundwater bursting from its ripped seams to create not only
violent floods, but also the unique fracture patterns seen at
Sacra Mensa and Sacra Fossae.

Snow and ice melted by volcanic eruptions also likely contributed
to torrential, muddy outpourings, while glacial activity may have
further shaped the channel system.

Now silent, one can only imagine from examples on Earth the roar
of gushing water that once cascaded through Kasei Valles,
undermining cliff faces and engulfing craters, and eventually
flooding onto the plains of Chryse Planitia.
Received on Thu 06 Jun 2013 01:02:27 PM PDT