Mineralogy at Meridiani Planum from the Mini-TES Experiment on the Opportunity Rover

Area of Science:

• Planetary Science
• Mineralogy
• Astrogeology

Background:

• The Martian surface at Meridiani Planum exhibits diverse geological features.
• Orbital spectroscopy provided initial insights into mineral composition.
• Understanding surface composition is key to deciphering Mars's geological history.

Purpose of the Study:

• To determine the mineral abundances and compositions of surface materials at Meridiani Planum using the Miniature Thermal Emission Spectrometer (Mini-TES).
• To investigate the origin and evolution of geological formations on Mars.

Main Methods:

• In-situ mineralogical analysis using the Miniature Thermal Emission Spectrometer (Mini-TES) aboard the Opportunity rover.
• Spectral analysis of outcrops, rocks, and soils.
• Comparison of Mini-TES data with orbital spectroscopy and Martian meteorite compositions.

Main Results:

• Observed coarse crystalline hematite and olivine-rich basaltic sands, consistent with orbital predictions.
• Identified outcrops of aqueous origin composed of magnesium and calcium sulfates (15-35% by volume), a high-silica component (20-30%), and hematite.
• Detected only minor jarosite in Mini-TES spectra and a hematite signature in millimeter-sized spherules.
• Characterized basaltic materials as plagioclase-rich with olivine, similar to orbital data.
• Analyzed Bounce rock as clinopyroxene-dominated, resembling basaltic Martian meteorites.
• Matched bright wind streak material to global Martian dust.

Conclusions:

• The mineralogical data indicate a complex geological history at Meridiani Planum.
• The presence of sulfates and associated minerals suggests past aqueous processes.
• The transition from waterlain rocks covered by basaltic sands points to a change from a wet to a physically weathered, arid environment.