🔥 This substance discovered on Mars only synthesizes above 212°F (100°C)

The planet Mars continues to reveal unexpected compounds within its rock formations.

For years, unusual spectral signals captured from space have intrigued the scientific community. Recently, work published in Nature Communications proposes an appealing explanation: these signatures could correspond to a hydrated iron sulfate never observed before, requiring strong heat to form. This new mineral phase was identified near the vast Valles Marineris canyon, an area rich in ancient deposits.


The examined areas, Aram Chaos and the Juventae Chasma plateau, show well-defined sulfate layers. These strata formed when sulfate-rich water slowly disappeared, leaving behind minerals. Subsequently, heat from volcanic or geothermal activities altered these deposits. This sequence allowed the creation of the hydrated iron sulfate phase.

To understand this process, laboratory experiments simulated the heating of hydrated sulfates. When the temperature exceeds 122°F (50°C), polyhydrated sulfates become monohydrated. Beyond 212°F (100°C), they transform into hydrated iron sulfate. These results match observations made on Mars, where this substance only appears in limited places.

The chemical reaction at the origin of this mineral requires oxygen, a gas present in small quantities in the Martian atmosphere. During the transformation, water is released. This indicates that Mars experienced conditions where heat and oxygen could interact with surface minerals, long after the period when water was abundant.

This analysis suggests that some parts of Mars remained thermally active more recently than thought. Hydrated iron sulfate could therefore serve as a marker to trace the planet's geological history. It also offers leads to better understand past environments that could have been conducive to life.

Detecting minerals from Martian orbit

To analyze the surface of Mars without landing a rover, scientists use instruments onboard orbiters. One of the most important is the CRISM spectrometer, which measures light reflected by the ground in different wavelengths, particularly in the infrared.

Each mineral absorbs and reflects light in a unique way, creating a characteristic spectral signature. By comparing these signatures with databases established in the laboratory, researchers can identify minerals present remotely. This non-invasive method allows for mapping vast areas quickly.

Spectral data reveal not only mineral composition, but also the structure of geological layers. For example, they can show how sulfates are stratified, indicating sequences of deposition and transformation due to events like evaporation or heating.

These orbital techniques are complementary to ground missions. They provide a valuable overview to target the most interesting sites for future explorations, searching for clues about the history of water and geological activity on Mars.