Ascraeus Mons is the northernmost of three shield volcanoes (known as the Tharsis Montes) near the equator of Mars. Its complex caldera (volcanic crater) is composed of several discrete centers of collapse, where the older collapse features are cross-cut by more recent collapse events. The lowermost circular floor preserves the last lava flooding event that followed the last major collapse approximately 100 million years ago. The southern wall of the caldera has at least 3 km of vertical relief with an average slope of at least 26 degrees (from horizontal). The caldera complex truncates several lava flows, indicating that the flows predate the collapse event and that their source areas have been destroyed by the caldera formation.
The image was taken on January 31, 2004, by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft.
Color composite of the infrared, green and blue channels of the HRSC, adapted to a Mars-like appearance.
The image resolution is 15 m per pixel. North is up.
(Image Credit: ESA/DLR/FU Berlin/astroarts.org)
