[meteorite-list] Martian Volcanoes May Be Active

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Sep 7 12:21:46 2005
Message-ID: <200509071620.j87GKcK25856_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/1/hi/sci/tech/4219858.stm

Martian volcanoes 'may be active'
By Paul Rincon
BBC News
September 7, 2005

Fields of volcanic cones discovered at the North Pole of Mars suggest
the Red Planet could still be geologically active, scientists have said.

The cones, seen in images from Europe's Mars Express probe, have no
blemishes from impact craters.

This suggests the volcanoes erupted very recently and that the sites
could have ongoing volcanism.

Mars Express scientist Gerhard Neukum presented the results at a
conference in Cambridge.

"Mars is a planet that was very recently active - maybe one, or two, or
three million years ago. And in some areas, I have the impression it is
really ongoing," said Dr Neukum, of the Free University in Berlin, Germany.

Future eruptions

But what cannot be determined is when, if at all, some of these
volcanoes might erupt again: "It could be a million years from now, it
could be tomorrow," he added.

Dr Neukum acts as the principal investigator for the High Resolution
Stereo Camera (HRSC) on Mars Express, which took the images in which the
cones were discovered.

There may be 50-100 of the volcanic cones covering a flank of the North
Pole about one million square kilometres in area. They are between 300m
(980ft) and 600m (1,970ft) tall, said Dr Neukum.

In addition to the North Pole, other regions with recent - and possibly
ongoing - activity on Mars include parts of Tharsis - home to the
volcano Olympus Mons - parts of Elysium and the so-called
highland-lowland boundary.

By counting the number of craters on the surfaces of Solar System
objects, scientists can estimate the age of those surfaces.

If they are heavily cratered, they are deemed older, while smoother
surfaces are considered younger. This assumes a constant cratering rate
since the heavy bombardment that terrestrial planets underwent about
four billion years ago.

Fresh cones

The cones appear to be fresh with no discernible evidence of cratering.
Dr Neukum admitted it was possible the cones could be ancient features
that have been eroded by wind, but added that this was unlikely.

"I don't see any wind-related features in the region. We should see it
and we should see the remains of craters somewhere. But we don't," he
told the BBC News website.

Volcanic activity appeared to have peaked on Mars at around 1.5 billion
years ago, Dr Neukum said, adding: "Mars is still active within certain
limits; it's still not dead."

Dr Neukum thinks that volcanic activity strongly influences glacial
activity on Mars. This is because on the Red Planet, eruptions also
mobilise water.

In some cases, this water freezes and forms glaciers, says Dr Neukum.
But other scientists believe glacial activity on the planet is more
strongly influenced by the inclination of Mars in its orbit around the Sun.

The Mars Express results were presented at the American Astronomical
Society Division of Planetary Sciences meeting in Cambridge, UK.
Received on Wed 07 Sep 2005 12:20:38 PM PDT