What Elements Are on the Surface of Mars?

Oxygen

• Despite its thin atmosphere, Mars contains a good deal of oxygen. However, the planet's oxygen occurs almost exclusively as a mineral oxide bound to other elements. Mars gets its red soil from iron oxides, a more scientific name for rust. The Martian atmosphere, although thin, contains sufficient carbon dioxide and water vapor to oxidize the planet's soil. Earth also has areas of reddish iron-rich soil, but as Mars has no concealing vegetation, the entire planet appears varying shades of red.

Silicon

• The second most abundant element on the Martian surface, silicon compounds make up much of the planet's rocks and sands. Silicates include silicon dioxide, a mineral abundant on Earth in the form of quartz, agate, amethyst and flint. Tiny particles of silicon dioxide make up the majority of Earth's beaches. While Mars has no liquid water and therefore no beaches, it has an abundance of silicon-rich sand.

Iron

• The surface of Mars gets its red coloration from red iron oxides, but iron also makes up much of its darker portions, too. The third most abundant element on the Martian surface, iron forms a black compound when it oxidizes partially. On Mars, these darker hues blend with brighter iron oxides and paler silicon dioxide particles to give the planet its variegated coloration.

Magnesium and Calcium

• These two alkaline earth metals have similar properties and occur on the Martian surface in similar abundance. The fourth and fifth most abundant elements respectively, magnesium and calcium on Mars typically form anhydrite compounds with sulfur and oxides with oxygen. One marked difference between Earth's calcium compounds and Mars' is that Earth appears to be richer in calcium carbonate than Mars. Carbonate minerals occur on Mars, too, but with less frequency than they do on Earth. Scientists theorize that Martian calcium and magnesium carbonates came from reactions with the carbon dioxide in the planet's atmosphere.