Terra Sirenum

On the southwest edge of the immense volcanic region of Tharsis, lava from its giant volcanoes flowed down to meet the old cratered landscape of Terra Sirenum. Scientists cannot say how many years separate the flows from the terrain they engulfed, but the relationship between the two tells a complex tale.

This false-color mosaic image combines separate frames taken by the Thermal Emission Imaging System (THEMIS), a special camera on NASA's Mars Odyssey spacecraft.

Image credit: NASA/JPL-Caltech/Arizona State University