Meridiani Planum

Meridiani Planum is a plain located 2 degrees south of Mars' equator, in the westernmost portion of Sinus Meridiani. It hosts a rare occurrence of gray crystalline hematite. On Earth, hematite is often formed in hot springs or in standing pools of water; therefore, many scientists believe that the hematite at Meridiani Planum may be indicative of ancient hot springs or that the environment contained liquid water. The hematite is part of a layered sedimentary rock formation approximately 200 meters thick. Other features of Meridiani Planum include volcanic basalt and impact craters.

Meridiani Planum is the target landing site for NASA's MER-B rover, named "Opportunity." It was also the target landing site for Mars Surveyor 2001, which was cancelled after the failures of the Mars Climate Orbiter and Mars Polar Lander missions.