Olympus Mons the -diameter Pangboche crater (). The craters are notable for being two of several suspected source areas for shergottites, the most abundant class of Martian meteorites. As a shield volcano, Olympus Mons resembles the shape of the large volcanoes making up the Hawaiian Islands. The edifice is about wide. Because the mountain is so large, with complex structure at its edges, allocating a height to it is difficult. Olympus Mons stands above the Mars global datum, and its local relief, from the foot of the cliffs which form its northwest margin to its peak, is nearly (a little over twice
Tectonics of Mars in elevation than the southern highlands, and have a much lower crater density, indicating a younger surface age. The underlying crust is however thought to be the same age as that of the southern highlands. Unlike the southern highlands, magnetic anomalies in the northern plains are sparse and weak. The Tharsis plateau, which sits in the highland-lowland boundary, is an elevated region that covers roughly one quarter of the planet. Tharsis is topped by the largest shield volcanoes known in the solar system. Olympus Mons stands 24 km tall and is nearly 600 km in diameter. The adjoining Tharsis Montes