Mars has undergone massive volcanic upheavals

[SilverGuru]

London, March 17 (IANS) Mars has undergone massive volcanic upheavals
that alternatively spewed lava and water onto its surface, giving the
red planet its current contours......


Mon, Mar 17 03:16 PM

London, March 17 (IANS) Mars has undergone massive volcanic upheavals
that alternatively spewed lava and water onto its surface, giving the
red planet its current contours.

German scientists have come to this conclusion after viewing the
latest images of those contours - captured by the high-resolution
stereo camera (HRSC) of Mars Express, the European Space Agency's
(ESA) spacecraft circling the planet, reports Scincedaily.

'We can now determine the ages of large regions and resurfacing events
on the planet,' said Gerhard Neukum of Berlin's Freie Universitat. And
he attributed those to volcanic eruptions spreading lava across Mars'
surface.

Neukum, who led a study of the images, believes that the sculpting of
the Martian surface has not proceeded steadily.

Rather, Mars has been wracked by violent volcanic activity five times
in the past, after the early supposedly warmer and wetter phase, more
than 3.8 billion years ago. In between these episodes, the planet has
been relatively calm.

The five volcanic episodes stretch throughout Martian history,
occurring around 3.5 billion years ago, 1.5 billion years ago, 400-800
million years ago, 200 million years ago and 100 million years ago.

The ages have been estimated by counting the number of small craters
that appear on the landscape. The idea is simple: the older the
surface, the more craters it will have accumulated as meteorites of
all sizes have struck over the ages.

There has been a debate recently about the validity of this method.
However American researchers, analysing seven years' worth of images
from the Mars Orbiter Camera (MOC) on NASA's Mars Global Surveyor,
have found new craters appearing on the surface during that time.

'The present day cratering rate can be calculated from their
observations,' says Neukum. It fits very closely with the cratering
rate he established from the Mars Express data with Bill Hartmann,
Planetary Science Institute, Tucson, Arizona.

Far from revealing a geologically dead world, Mars Express is exposing
a place of subtle activity that could still erupt into something more
spectacular.

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