Fe-Rich Fossil Vents as Mars Analog Samples: Identification of Extinct Chimneys in Miocene Marine Sediments Using...

Area of Science:

• Geochemistry
• Astrobiology
• Microbiology

Background:

• Hydrothermal systems on Earth circulate iron-rich fluids, forming mineral deposits that reflect chemical conditions and microbial life.
• Iron-rich hydrothermal sites on Mars are prime targets for astrobiological research and life detection missions.
• Terrestrial hydrothermal vents serve as analogs for understanding potential Martian environments.

Purpose of the Study:

• To analyze an extinct hydrothermal chimney from the Jaroso system (Spain) as a Mars analog.
• To investigate the presence of microbial colonization within iron-rich crusts.
• To assess the utility of Raman spectroscopy for habitability studies.

Main Methods:

• Raman spectroscopy
• X-ray diffraction
• Scanning electron microscopy with energy dispersive X-ray spectroscopy

Main Results:

• The iron crust exhibited mineral microstructures (stalks, filaments), iron oxyhydroxide phases (goethite, ferrihydrite), and organic signatures (carotenoids, organopolymers).
• Resonance Raman spectroscopy identified pigments, and Raman microimaging confirmed preserved organics associated with iron oxyhydroxides.
• These findings provide clear evidence of microbial colonization within the iron crust.

Conclusions:

• Raman spectroscopy is a powerful tool for documenting habitability in ancient hydrothermal environments.
• The analyzed hydrothermal pipes are valuable terrestrial Mars analog specimens.
• These analogs support preparatory work and data interpretation for robotic Mars exploration missions.