From the very pure ice in the north polar cap of Mars
An international team led by researchers at the laboratory planetology in Grenoble has obtained results on the north polar cap from Mars. Using data radar from Mars Reconnaissance Orbiter from NASA, the astronomers have now confirmed the abundance of water Mars in the form of ice, but also very high purity (95%) , with a concentration of impurities at the edge of the polar cap. These results are important elements to develop a comparative planetology Martian ice and land. This work is published in the journal Geophysical Research Letters.
The polar layered deposits - so-called abused ice caps - are the largest reservoirs of water on the surface from Mars. Their volume total is 2 to 3 million km3. The physical properties of ice and their spatial variations are largely unknown.
140 000 measurement points acquired by the SHARAD subsurface radar were analyzed in the Gemina Lingula region, which represents a quarter of the total area of the north polar cap. Maps of dielectric properties of the volume of ice were obtained. A sudden drop of dielectric constant northwest of Gemina Lingula can be explained by a rise of about 250 m from the base the shell, implying the existence of a geological underlying.
This study demonstrates once again the abundance of water ice on Mars, confirming its role in the evolution of the planet . In addition, analysis of these results shows that the ice is pure at 95%, the impurities with a radial distribution, with a higher concentration at the edge of the shell. The analysis of purity of the ice is important for the rheology of the system and the distribution of impurities is a marker for the Martian atmosphere. The very precise results were obtained will help to better characterize the Martian ice and its interaction with the environment. Martian ice and land with the same crystalline structure, but the global environment is very different, this comparative planetology caps on Mars and land, could significantly improve our understanding of their developments.
