News|Articles|July 30, 2026

New Spectroscopic Fingerprints Could Sharpen the Hunt for Ancient Martian Life

Author(s)Will Wetzel, Spectroscopy Staff

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Key Takeaways

Iron-bearing vivianite and greigite are compelling targets because, on Earth, they arise predominantly in organic-rich, oxygen-poor settings via bacteria-driven biocrystallization processes.
Conventional vibrational spectroscopy above 500 cm⁻¹ provides limited discriminative power for these minerals, increasing ambiguity versus chemically similar compounds.
Terahertz time-domain spectroscopy interrogates 10–130 cm⁻¹ lattice vibrations, revealing dense, mineral-specific spectral features largely absent at higher frequencies.
Density functional theory simulations assign observed THz peaks to specific atomic motions and help distinguish vivianite/greigite from metavivianite and ludlamite.
Precompiled low-frequency spectral libraries could inform instrument selection for future Mars missions and improve confidence in in situ or returned-sample mineral identification.

An upcoming poster at the American Chemical Society (ACS) Fall 2026 Meeting will present how terahertz spectroscopy is being used to study Mars.

Recently, researchers at Syracuse University conducted a study that tested their terahertz (THz) spectroscopy method to see if it could improve their ability to detect two iron-bearing minerals on Mars. The findings will be presented by Adler Cary at a poster session on Tuesday, August 25, from 7 to 9 p.m. EDT at the McCormick Place Convention Center in Chicago, Illinois.¹

Why is it important to study iron-bearing minerals on Mars?

Currently, scientists are conducting many experiments on Mars in an effort to learn more about the planet. Much of these experiments are designed to learn more about its atmosphere and its origin, including investigating signs of past life. Iron-bearing minerals are thought to be a strong indicator of past microbial life on the planet, which is why scientists are keen on using new analytical scientific instrumentation to detect these minerals.¹

What iron-bearing minerals were detected on Mars?

NASA’s Mars Perseverance rover has identified vivianite and greigite on the planet. These minerals were found in the Jezero Crater, along with other organic minerals.^1,2 On Earth, these minerals form almost exclusively in organic-rich, oxygen-poor environments through biocrystallization processes driven by bacteria.¹ Their co-occurrence on Mars has drawn scientific interest as a possible biosignature but confirming their identity remotely or in returned samples has been difficult using conventional methods.¹

Standard vibrational spectroscopy, which identifies minerals by the frequencies at which their chemical bonds vibrate, typically examines a frequency range above 500 wavenumbers. In that range, vivianite and greigite produce relatively few distinguishing spectral features. As a result, it sometimes difficult to distinguish them from similar compounds with confidence.¹

What did the researchers do in their study?

During the poster session, Cary will go through the study’s methodology and results. Cary will explain how by using THz time-domain spectroscopy, the team can examine a lower frequency window, between 10 and 130 wavenumbers, where lattice vibrations occur.¹ According to the research, this region contains numerous mineral-specific features that are largely absent at higher frequencies, offering a clearer analytical signature for each mineral.¹

How did the researchers interpret the experimental data?

For their study, Cary and the team paired their spectroscopic measurements with density functional theory simulations, which is a computational technique that models atomic-scale behavior using periodic boundary conditions.¹ This allowed the team to link specific spectral peaks to the precise atomic motions producing them. The study also modeled two related minerals, metavivianite and ludlamite, to test the method's ability to distinguish between chemically similar compounds.¹

This talk suggests that THz spectroscopy could be adapted and used in future mission designs, including for instruments that are carried on rovers or landers or used in laboratory analysis of samples returned from Mars.¹ By cataloguing distinctive low-frequency fingerprints for these minerals now, the researchers aim to give future missions a more reliable analytical basis for identifying them in the field.¹

When does the American Chemical Society (ACS) Fall 2026 Meeting take place?

The ACS Fall 2026 Meeting is set to take place from August 23 to 27^th, 2026. Set in Chicago this year, this conference is set to welcome thousands of researchers, students, and industry professionals. Apart from poster sessions, the conference program will also contain several keynote presentations, oral technical sessions, and other networking and social events.³

You can learn more about the upcoming ACS conference at the following link: https://www.acs.org/events/fall.html.

References

Cary, A. Exploring Iron Bearing Martian Minerals Using Terahertz Spectroscopy and Density Functional Theory. Presented at the American Chemical Society Fall 2026 Meeting, Chicago Illinois, August 25, 2026. Available at: https://acs.digitellinc.com/live/37/page/1374?search=spectroscopy&page=9&window-au6rhv
Workman, Jr., J. Mars Rover Uses Spectroscopy to Detect Diverse Organic-Mineral Associations in Jezero Crater. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/mars-rover-uses-spectroscopy-to-detect-diverse-organic-mineral-associations-in-jezero-crater (accessed July 24, 2026).
Wetzel, W. Why Spectroscopists Should Attend the ACS Fall 2026 Conference. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/why-spectroscopists-should-attend-the-acs-fall-2026-conference (accessed July 23, 2026).