Meridiani Planum is a plain located 2 degrees south of
Mars' equator (centered at ), 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.