Mars with ice, shaken, not stirred

October 25, 2007

Boulder, CO, USA - Mars, like Earth, is a climate-fickle water planet. The main difference, of course, is that water on the frigid Red Planet is rarely liquid, preferring to spend almost all of its time traveling the world as a gas or churning up the surface as ice. That's the global picture literally and figuratively coming into much sharper focus as various Mars-orbiting cameras send back tomes of unprecedented super high-resolution imagery of ever vaster tracts of the planet's surface.

What were just a few years ago small hints about Mars' water and climate, as seen in a few "postage-stamp" high-resolution images and topography, have given way to broader theory that explains not only the features seen on the planet today, but imply a dynamic history of Martian climate change.

"When you have postage stamps, it's like studying a hair on an arm instead of the whole arm," said Mars researcher James Head III of Brown University. Head will present the latest integrated global view of Martian surface features and how they fit with Martian climate models on Sunday, 28 October 2007, at the Geological Society of America Annual Meeting in Denver.

The pictures now reveal a range of ice-made features that show a strong preference to certain latitudes, Head explains. As on Earth, latitude-dependent features can mean only one thing: latitude-dependent climate.

The signs of water ice are obvious today at Mars' poles. But as you move towards the equator, there is plenty of evidence of water ice having shaped the surface in different ways not so long ago.

Not far from either pole, for instance, widespread bumpy polygonal patterned ground suggests the contraction and expansion of icy permafrost ground - very similar to that seen in Earth's Arctic and Antarctic. Next, between 30 and 60 degrees latitude in both hemispheres, the patterned ground gives way to a pervasive pitted texture of once ice-rich dust deposits. Even closer to the equator on the flanks of Mars' equatorial volcanoes are compelling signs of large glaciers, almost exactly like those of Earth. There are also craters which seem to be filled with glacial debris and small valleys which drop precipitously into canyons - which on Earth is usually a strong indicator that a glacier once filled and widened the canyon.

As for where all the ice went, much of it was sublimed away and deposited at the poles. The ice rules the more temperate latitudes only when the tilt of Mars' spin axis is far more extreme than today - up to 45 degrees. That tilt, or obliquity, exposed the poles to a lot more sun during the course of a Martian year, according to climate models, evaporating the ice caps. That same water refroze on the surface in the then darker and colder equatorial and middle latitudes, hence all the evidence of ice and glaciers.

"It's a quest to understand the Martian water cycle," said Head describing his work.

Among the instruments used to study Mars are the Mars Global Surveyor's Laser Altimeter (MOLA) and Camera (MOC), the Mars Reconnaissance Orbiter's Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE), and the Mars Express's High Resolution Stereo Camera (HRSC).
-end-
**WHERE & WHEN**

Geological Framework of the Northern Lowlands of Mars and Evidence for Extensive Amazonian Climate Change Processes
Sunday, October 28, 2007, 8:40 a.m. - 9:00 a.m.
Colorado Convention Center Room 405
View abstract: http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_128232.htm

**CONTACT INFORMATION**

James W. Head, Professor, Geological Sciences, Brown University
Telephone: +1-401-863-2526
Email: James_Head@Brown.edu
URL: http://research.brown.edu/myresearch/James_Head

For information and assistance during the GSA Annual Meeting, 27-31 October, contact Ann Cairns in the onsite newsroom, Colorado Convention Center Room 604, +1-303-357-1056, acairns@geosociety.org.

**IMAGES AVAILABLE**

The following images may be downloaded from the Malin Space Science Systems web site. Please credit their use as "Images courtesy of NASA/JPL/Malin Space Science Systems."

MARTIAN GLACIERS
http://www.msss.com/mars_images/moc/top102_Dec98_rel/fretted/

Caption:
Mid-latitude Martian valley deposits closely resemble the ice flow patterns created by terrestrial glaciers. On Mars the ice is either still there or, unlike on Earth, the ice sublimed away (went from ice to gas without a liquid phase) and dropped the lines of glacial debris on the valley floor.

FROST-PATTERNS
http://www.msss.com/mars_images/moc/2005/10/03/
http://www.msss.com/mars_images/moc/polygons_5_02/

Caption:
At higher latitudes on Mars patterned ground similar to that of the Arctic and Antarctic suggests there is expansion and contraction of the icy ground from cycles of warming and cooling.

POLAR CAPS
North: http://www.msss.com/mars_images/moc/may_2000/n_pole/
South: a) http://www.msss.com/mars_images/moc/2003/06/07/
b)http://www.msss.com/mars_images/moc/2005/08/30/

Caption:
Today's Martian polar caps were once tilted more towards the Sun, which drove the ice to lower latitudes, creating glaciers and other icy features.

Geological Society of America

Related Mars Articles from Brightsurf:

Water on ancient Mars
A meteorite that originated on Mars billions of years ago reveals details of ancient impact events on the red planet.

Surprise on Mars
NASA's InSight mission provides data from the surface of Mars.

Going nuclear on the moon and Mars
It might sound like science fiction, but scientists are preparing to build colonies on the moon and, eventually, Mars.

Mars: Where mud flows like lava
An international research team including recreated martian conditions in a low-pressure chamber to observe the flow of mud.

What's Mars made of?
Earth-based experiments on iron-sulfur alloys thought to comprise the core of Mars reveal details about the planet's seismic properties for the first time.

The seismicity of Mars
Fifteen months after the successful landing of the NASA InSight mission on Mars, first scientific analyses of ETH Zurich researchers and their partners reveal that the planet is seismically active.

Journey to the center of Mars
While InSight's seismometer has been patiently waiting for the next big marsquake to illuminate its interior and define its crust-mantle-core structure, two scientists, have built a new compositional model for Mars.

Getting mac and cheese to Mars
Washington State University scientists have developed a way to triple the shelf life of ready-to-eat macaroni and cheese, a development that could have benefits for everything from space travel to military use.

Life on Mars?
Researchers from Hungary have discovered embedded organic material in a Martian meteorite found in the late 1970s.

New evidence of deep groundwater on Mars
Researchers at the USC Arid Climate and Water Research Center (AWARE) have published a study that suggests deep groundwater could still be active on Mars and could originate surface streams in some near-equatorial areas on Mars.

Read More: Mars News and Mars Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.