Environmental Mineralogy
Mineral-light interactions on Earth and Mars: Coatings, photochemistry, and surface reactivity
Co-Conveners
Qian Fang, China University of Geosciences-Wuhan
Yanzhang Li, Carnegie Institution for Science
Runliang Zhu, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences
Robert Hazen, Carnegie Institution for Science
Michael Hochella, Virginia Tech
Anhuai Lu, Peking University
Solar radiation is a fundamental driver of surface and near-surface processes on terrestrial planets. On both Earth and Mars, mineral surfaces are frequently covered by naturally occurring coatings (e.g., desert varnish, rock coating, soil cutan iron/manganese-rich crust) enriched in semiconducting transition metal oxides. Rather than being passive environmental records, these widespread mineral coatings act as highly active natural photocatalysts.
Under solar irradiation, these semiconducting coatings trigger photoelectron-photohole generation, driving critical photochemical reactions at the mineral-fluid-gas interface. On Earth, these mineral-light interactions significantly influence global biogeochemical cycling, organic matter degradation, and the evolution of the critical zone. On Mars—characterized by intense ultraviolet (UV) radiation and a hyperarid, highly oxidizing environment—analogous photochemical processes are deeply tied to the generation of reactive oxygen species (ROS), the formation of perchlorates, the preservation or destruction of potential organic biosignatures, and the planet's atmospheric evolution. Understanding these light-induced interface reactions is critical for interpreting spectral data returned by active rovers (e.g., Perseverance, Curiosity, Tianwen-1) and orbiters, and holds the key to answering fundamental questions about Martian habitability and the origin of life. By bringing together the terrestrial and Martian perspectives, this session aims to foster cross-disciplinary dialogue. We aim to scale from the atomic mechanisms of photoelectron transfer to global-scale planetary weathering and climate feedbacks.
We warmly invite contributions from mineralogy, geochemistry, planetary science, astrobiology, and materials science. Broad topics of interest include, but are not limited to:
Genesis and evolution of coatings: Formation mechanisms, micro-structures, and optical properties of natural rock varnishes, evaporites, and weathering crusts on Earth and Mars.
Photochemical reactivity: Sunlight-driven catalytic processes, element mobility, and redox reactions at the mineral-water-gas interfaces.
Astrobiology and prebiotic chemistry: The role of mineral-light interactions in the synthesis or destruction of organic matter, origin of life scenarios, and the preservation of biosignatures.
Planetary exploration and remote sensing: Interpreting orbital and rover-based spectral data through the lens of photo-altered mineral surfaces and simulated Martian environments.
Advanced methodologies: Multi-scale characterization techniques (e.g., atom probe tomography, synchrotron radiation, in-situ spectroscopy, isotopic tracing) and computational modeling of surface reactivity.
Applied perspectives: Insights from natural semiconducting minerals for engineered photocatalysts, environmental remediation, and In-Situ Resource Utilization (ISRU) for future space exploration.
Join us to illuminate the profound connections between light, minerals, and the evolution of terrestrial planets!
