Meridiani Planum

Meridiani Planum is a plain located 2 degrees south of Mars' equator (centered at 0°12′N 357°30′E / 0.2°N 357.5°E / 0.2; 357.5), in the westernmost portion of Terra 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 about 200 to 800 meters thick. Other features of Meridiani Planum include volcanic basalt and impact craters.

Read more about Meridiani Planum:  Mars Rover Opportunity, A Summary, Opportunity Rover's Rocks and Minerals Discoveries At Meridiani Planum, Craters Within Meridiani Planum