1,2A. Mojarro (>10)
Journal of Geophysical Research: Planets, (in Press), (in Press)
Open Source Link to Article [DOI: 10.1029/2026JE009985]
1University of Maryland Baltimore County and Center for Research and Exploration in Space Science and Technology, NASA GSFC, Greenbelt, MD, USA
2Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA
Published by arrangement with John Wiley & Sons
The Viking missions landed two spacecraft on Mars each equipped with a pyrolysis‐gaschromatograph‐mass spectrometer system capable of detecting signs of life. Although working as intended,detections of chloromethane and dichloromethane were initially attributed to terrestrial contamination. Decadeslater, the Phoenix Mars Lander identified perchlorate salts in the Martian regolith that are known to catalyze theoxidation and chlorination reactions of organics. Subsequent analyses by the Sample Analysis at Mars (SAM)instrument suite aboard the Curiosity rover have since confirmed a variety of syngenetic chlorinatedhydrocarbons in Gale crater samples. However, the nature of the parent organic matter (exogenous, abioticendogenous, or biological) remains unresolved. Here we evaluate the Murchison (CM2) carbonaceous chondriteas a proxy for organic matter delivered to the surface of Mars by meteoritic and interplanetary dust particle infallover geologic timescales. We characterize the generation of chlorinated hydrocarbons during the pyrolysis ofMurchison in the presence of 1 and 5 wt.% calcium perchlorate. Experiments produced a suite of C1‐C7chlorinated hydrocarbons dominated by aromatic species, including compounds detected by both Viking andSAM. Increasing the perchlorate content from 1 to 5 wt.% did not amplify the relative abundances or diversity ofchlorinated products but rather preferentially oxidized parent organics. Results suggest that organics detected atGale crater represent a fraction of molecules liberated from a macromolecular source that is compositionallyconsistent with meteoritic organic matter. Unambiguously resolving the origin and diversity of Martian organicmatter may ultimately require the coordinated laboratory analysis of samples returned to Earth.
