Laser Topography of Mars Northern Ice Cap (IMAGE) University of Texas at Austin Caption Morphology of the north polar region of Mars. Spiral troughs are seen throughout the ice-rich polar cap (quasi-circular dome at center), and Chasma Boreale is the large canyon dividing the polar cap into two lobes. Chasma Boreale is the size of the Grand Canyon in the US and up to 2 kilometers deep. Shaded-relief image based on Mars Orbiter Laser Altimeter data. Credit NASA/GSFC Usage Restrictions Proper credit must be given to: NASA/GSFC License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.