sediments have extremely high sulfur content (as sulfates) and high phosphate levels.

The boundaries of the Meridiani Planum are not firmly fixed and accepted by the community of Mars planetary scientists. However, the boundaries of the hematite-bearing plain were operationally defined in the late 1990s and early 2000s by the extent of the orbital detection of the plain's surface hematite by the thermal emission spectrometer (TES) on the satellite Mars Global Surveyor. The various names for