Olympus Mons Martian surface atmospheric pressure is less than one percent of Earth's, the much lower gravity of Mars increases the atmosphere's scale height; in other words, Mars's atmosphere is expansive and does not drop off in density with height as sharply as Earth's. The composition of Olympus Mons is approximately 44% silicates, 17.5% iron oxides (which give the planet its red coloration) 7% aluminum, 6% magnesium, 6% calcium, and particularly high proportions of sulfur oxide with 7%. These results point to the surface being largely composed of basalts and other mafic rocks, which would have erupted as low viscosity lava flows
Olympus Mons unaware of standing on a very high mountain, as the slope of the volcano would extend far beyond the horizon, a mere 3 kilometers away. The typical atmospheric pressure at the top of Olympus Mons is 72 pascals, about 12% of the average Martian surface pressure of 600 pascals. Both are exceedingly low by terrestrial standards; by comparison, the atmospheric pressure at the summit of Mount Everest is 32,000 pascals, or about 32% of Earth's sea level pressure. Even so, high-altitude orographic clouds frequently drift over the Olympus Mons summit, and airborne Martian dust is still present. Although the average