Source: Discovery (Channel) Online News,
Wednesday, March 17, 1999
Crater Images Reveal Mars' Past
New Mars Global Surveyor images reveal complex layering that may
enable scientists to study the geologic history of ancient Mars the
same way it's studied here on Earth, by comparing and dating different
The images, unveiled Tuesday at the 30th Lunar and Planetary Science
Conference in Houston, show multiple complex layers in a part of Mars
where scientists had not expected to find it -- the ancient "cratered
highlands" of the planet's southern hemisphere.
"Geologists study the history of Earth by looking at layers," says Ken
Edgett, staff scientist for Malin Space Science Systems, which
operates the Surveyor's Mars Orbiter Camera. "We now have ample
evidence to believe that we can study the history of Mars the same
Rock layers on Earth reveal such things as the ages and duration of
lava flows, ocean sediments, and similar continent-building events.
While most of the layers on Mars are thought to be volcanic, a few of
the new images depict lighter-colored layers that on Earth might be
characterized as sedimentary deposits.
"I don't know what that is," Edgett says of one white layer visible
a new image, "but it isn't basalt."
Scientific consensus has held that the cratered highlands could be
likened to highlands on the moon, Edgett says. But the new images
suggest that the ancient terrain on Mars is much more geologically
complex -- and Earthlike -- than volcanic lunar highlands.
Even during the most ancient times on Mars, Edgett says, there were
far more complicated planetary processes taking place than anyone has
The newly released images, taken in April 1998 but only recently
analyzed and processed, show Tagus Vallis, a small canyon in the
planet's southern hemisphere. Layered rocks much like those found in
canyons on Earth can be seen in the upper slopes of the valley.
"This evidence of layering may completely change our ideas of what the
Martian highlands are like," says Carlton Allen, principal scientist
for Lockheed Martin at the Johnson Space Center. "It will open up
what's been a great area of ignorance concerning two-thirds of the
surface of Mars."
By Michael Ray Taylor in Houston, Discovery Online News
Picture: Malin Space Science Systems/NASA
Return to UFO Folklore !