Vast areas of low latitude subsurface ice found on Mars

March 9, 2011 By Nancy Atkinson
Color image of a region in Holden Crater. Credit: NASA/JPL/University of Arizona

There could be more subsurface ice on Mars than previously thought, and vast stretches of it may lie just south of the equator. Indeed, one of the proposed landing sites for the Mars Science Laboratory could hold the mother lode of enticing scientific prospects. Observations from two spacecraft, the Mars Reconnaissance Orbiter and Mars Express, have revealed potential subsurface ice deposits in areas just south of the equator, including one near Holden Crater, with an estimated reservoir of perennial subsurface water ice of about 50 – 500 kg m-2 just two or three meters beneath the surface. This is the first evidence of ice at “tropical” latitudes on Mars as low as 25 degrees.

In 2009, MRO observations revealed as low as 45 degrees North in a recent small impact crater, and permanent water ice at Mars’ poles is known to exist. But most robotic missions – and hopefully one day human missions – need to land closer to the equator to meet safety criteria and engineering constraints. As evidence, the four proposed landing sites for the MSL hover within 25 degrees of the equator.*

Of course, subsurface ice can’t be seen directly on Mars, but certain surface characteristics and thermal properties belie potential underground ice. The OMEGA (Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité ) onboard and CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) onboard the use near-infrared imaging spectrometers to measure solar radiation scattered by the surface, providing spectral images that have been used to assess the composition of both minerals and condensates on the surface of Mars.

What drew scientists to this region, were observed surface distributions of seasonal CO2 frost on pole facing slopes. Carbon dioxide ice usually only forms on the surface if there is a cold layer beneath, which can come from water ice or bedrock.

But in this case, Mathieu Vincendon and his team at Brown University concluded that bedrock couldn’t be responsible for creating the observed thermal properties that stores and releases heat two or three meters beneath the surface. Evidence of a uniform layer of bedrock stretching across the equatorial region has never been seen in orbital images, which would have been revealed by erosion or impact processes.

“Using different modeling hypotheses within the range of uncertainties leads to the result that water ice is present within one meter of the surface on all 20-30° pole facing slopes down to about 25°S,” the team writes in their paper. “ The relevant thermal depths probed are 2 or 3 meters. Hence, an ice rich layer that thick is implied, which leads to an estimated reservoir of perennial subsurface water ice of about 50 – 500 kg m-2 on steep slopes.”

The team believes that the subsurface ice could be possible remnants of the last ice age on Mars, and could provide water that will be needed for the future exploration of . More thermal measurements of seasonal temperature variations could help to derive more precise permafrost depths.

Holden crater is located at the edge of the subsurface water ice area at 26°S.

*Eberswalde Crater is -23.90 degrees S, Mawrth Vallis is 23.99 degrees N, Gale crater is -4.49 degrees S, and Holden is -26.4 degrees S.

Explore further: Layered Crater on Mars

Related Stories

Layered Crater on Mars

July 18, 2007

This image covers an impact crater roughly 4 kilometers (2.5 miles) in diameter. The subimage shows just a small segment of the crater rim (1336 x 889; 3 MB).

Channels from Mars Hale Crater

October 28, 2009

( -- This image from NASA's Mars Reconnaissance Orbiter shows channels to the southeast of Hale crater on southern Mars. Taken by the orbiter's High Resolution Imaging Science Experiment (HiRISE) camera, this ...

Image: Dark dune fields of proctor crater, Mars

November 29, 2010

The dark rippled dunes of Mars' Proctor Crater likely formed more recently than the lighter rock forms they appear to cover, and are thought to slowly shift in response to pervasive winds.

First Color Mars Images From New Orbiter

April 7, 2006

This is the first color image of Mars from the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter. The blankets of material ejected from the many small fresh craters are generally brighter and ...

Recommended for you

Solar eruptions could electrify Martian moons

October 18, 2017

Powerful solar eruptions could electrically charge areas of the Martian moon Phobos to hundreds of volts, presenting a complex electrical environment that could possibly affect sensitive electronics carried by future robotic ...

Potential human habitat located on the moon

October 18, 2017

A study published in Geophysical Research Letters confirms the existence of a large open lava tube in the Marius Hills region of the moon, which could be used to protect astronauts from hazardous conditions on the surface.

A solar-powered asteroid nursery at the orbit of Mars

October 18, 2017

The planet Mars shares its orbit with a handful of small asteroids, the so-called Trojans. Among them, one finds a unique group, all moving in very similar orbits, suggesting that they originated from the same object. But ...

Scientists dig into the origin of organics on Ceres

October 18, 2017

Since NASA's Dawn spacecraft detected localized organic-rich material on Ceres, Southwest Research Institute (SwRI) has been digging into the data to explore different scenarios for its origin. After considering the viability ...


Adjust slider to filter visible comments by rank

Display comments: newest first

3.5 / 5 (2) Mar 09, 2011
"Of course, subsurface ice cant be seen directly on Mars, but certain surface characteristics and thermal properties belie potential underground ice."

BELIE: 'to give a false impression of'

So these 'certain surface characteristics and thermal properties' give a false impression of ice then? So there isn't ice there after all?
not rated yet Mar 10, 2011
@Prufreda I believe the reason the article writer's use of the word belie might be attributed to incorrect use of a thesaurus. Hidden leads to concealed, and that doesn't sound brainy enough, concealed leads to belie. A thesaurus is useless if you don't understand the alternative words it gives you.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.