Giant floods of lava have covered much of the equatorial lowlands of Mars in the recent geological past. One such flood of lava passed through the narrow gap near the center of this HiRISE image.

The pass is only 2.3 km (1.4 miles) wide, yet the flows went on for another 500 km (300 miles) to the west. As the lava passed through the narrows, the surface of the flow became crumpled and broken, producing a rough surface. To the southeast, the flow moved more gently and the crust was slowly pushed up by liquid lava injected into the freezing lava flow.

Small irregular cones along the margins of the flow were created by explosions as water or ice underneath the lava flow boiled. While lava flows approaching this size have formed on Earth, the rapid erosion on our planet has destroyed the upper surfaces of the lava flows. Mars provides an extremely valuable opportunity to study aspects of giant lava flows that cannot be seen on Earth.
Written by: Laszlo P. Keszthelyi

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.