The recently identified mineral, Phalic Hydroxysullate, sheds light on the environmental conditions and history of Mars, hinting at potential past volcanic, ash, or hydrothermal activities.
A distinct spectral unit on the Juventue Plateau on Mars. Image credit: Bishop et al, doi: 10.1038/s41467-025-61801-2.
The compact reconnaissance imaging spectrometer (CRISM) on NASA’s Mars Reconnaissance Orbiter has gathered hyperspectral data, enabling the mapping of numerous minerals that enhance our understanding of Mars’ ancient geochemical history.
Various sulfate minerals have been identified both from orbit and during landing missions, utilizing spectral parameters, X-ray diffraction, and elemental composition to compare with minerals found on Earth.
In 2010, a unique spectral band was detected in the CRISM data from Mars, specifically on the plateau near Juvento Chasma and within the eroded impact crater Arum Chaos.
This spectral band did not match any known minerals, presenting challenges in mineral identification for over 15 years.
Initial laboratory studies suggested that dehydrated iron sulfate could be the source of this unidentified material.
“The data obtained from spectrometers can’t be utilized in that manner,” explains Dr. Mario Parent, a researcher at the University of Massachusetts Amherst.
“Data adjustments are necessary to account for atmospheric effects.”
“The sunlight reflecting off the minerals and CRISM passes through the Martian atmosphere twice,” he continues. “There are scattering molecules and gases that absorb light.” For instance, Mars has a high concentration of carbon dioxide, which can distort the data.
By employing a deep learning artificial intelligence method, researchers can map both known and unknown minerals, automatically identifying anomalies in individual image pixels.
This technique has revealed additional locations with similar spectral bands and clarified other spectral features.
With refined properties, researchers were able to replicate the minerals in the lab and identify the enigmatic compound as hydroxysulfate.
“Materials formed in laboratory conditions may represent new minerals due to their unique crystal structure and thermal durability,” states Dr. Janice Bishop, a researcher at the SETI Institute and NASA’s Ames Research Center.
“However, it is imperative to find them on Earth to officially classify them as new minerals.”
Hydroxyacids are formed at elevated temperatures (50-100 degrees Celsius) in the presence of oxygen and water under acidic conditions.
“When will we observe this material once we develop a mineral attribution and obtain the necessary indicators of a specific material?” Dr. Parente questions.
Scientists deduced that it formed in Arum Chaos due to geothermal heat, while the same minerals likely originated in Juvento from volcanic activity involving ash or lava.
They speculate this may have occurred during the Amazonian era, which is estimated to be under 3 billion years ago.
“Factors such as temperature, pressure, and pH are critical indicators of what the paleoclimate was like,” states Dr. Parente.
“The existence of this mineral adds depth to our understanding of Martian processes.”
“Some regions of Mars have been chemically and thermally altered more recently than previously thought, providing new insights into the planet’s dynamic surface and its potential to support life.”
Study published in the journal Nature Communications.
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Jl Bishop et al. 2025. The properties of iron hydroxythrusa acid on Mars and the implications of the geochemical environment that supports its formation. Nat commun 16, 7020; doi:10.1038/s41467-025-61801-2
Source: www.sci.news
