Mars' climate in flux: Mid-latitude glaciers

October 17, 2005

New high-resolution images of mid-latitude Mars are revealing glacier-formed landscapes far from the Martian poles, says a leading Mars researcher.

Conspicuous trains of debris in valleys, arcs of debris on steep slopes and other features far from the polar ice caps bear striking similarities to glacial landscapes of Earth, says Brown University's James Head III. When combined with the latest climate models and orbital calculation for Mars, the geological features make a compelling case for Mars having ongoing climate shifts that allow ice to leave the poles and accumulate at lower latitudes.

"The exciting thing is a real convergence of these things," said Head, who presented the latest Mars climate discoveries on Sunday, 16 October, at the Annual Meeting of the Geological Society of America in Salt Lake City.

"For decades people have been saying that deposits at mid and equatorial latitudes look like they are ice-created," said Head. But without better images, elevation data and some way of explaining it, ice outside of Mars' polar regions was a hard sell.

Now high-resolution images from the Mars Odyssey spacecraft's Thermal Emission Imaging System combined with images from the Mars Global Surveyor spacecraft's Mars Orbiter Camera and Mars Orbiter Laser Altimeter can be compared directly with glacier features in mountain and polar regions of Earth. The likenesses are hard to ignore.

For instance, consider what Head calls "lineated valley fill." These are lines of debris on valley floors that run downhill and parallel to the valley walls, as if they mark some sort of past flow. The same sorts of lines of debris are seen in aerial images of Earth glaciers. The difference is that on Mars the water ice sublimes away (goes directly from solid ice to gas, without any liquid phase between) and leaves the debris lines intact. On Earth the lines of debris are usually washed away as a glacier melts.

The lines of debris on Mars continue down valleys and converges with other lines of debris - again, just like what's seen on Earth where glaciers converge.

"There's so much topography and the debris is so thick (on Mars) that it's possible some of the ice might still be there," said Head. The evidence for present day ice includes unusually degraded recent impact craters in these areas - just what you'd expect to see if a lot of the material ejected from the impact was ice that quickly sublimed away.

Another peculiarly glacier-like feature seen in Martian mid-latitudes are concentric arcs of debris breaking away from steep mountain alcoves - just as they do at the heads of glaciers on Earth.

As for how ice could reach Mars lower latitudes, orbital calculations indicate that Mars may slowly wobble on its spin axis far more than Earth does (the Moon minimizes Earth's wobble). This means that as Mars' axis tilted to the extremes - up to 60 degrees from the plane of Mars' orbit - the Martian poles get a whole lot more sunshine in the summertime than they do now. That extra sun would likely sublime water from the polar ice caps, explains Head.

"When you do that you are mobilizing a lot of ice and redistributing it to the equator," Head said. "The climate models are saying it's possible."

It's pure chance that we happen to be exploring Mars when its axis is at a lesser, more Earth-like tilt. This has led to the false impression of Mars being a place that's geologically and climatically dead. In fact, says Head, Mars is turning out to be a place that is constantly changing.
-end-
Lineated Valley Fill at the Dichotomy Boundary on Mars: Evidence for Regional Mid-Latitude Glaciation View abstract: http://gsa.confex.com/gsa/2005AM/finalprogram/abstract_94125.htm

IMAGES AVAILABLE
Visit http://www.geosociety.org/news/pr/05-37.htm

CONTACT INFORMATION

During the Geological Society of America Annual Meeting, 16-19 October, contact Ann Cairns at the GSA Newsroom, Salt Palace Convention Center, for assistance and to arrange for interviews: +1-801-534-4770.

After the meeting contact:

James Head III
Department of Geological Sciences
Brown University, Providence, RI
Phone: +1-401-863-2526
E-mail: James_Head_III@brown.edu

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.