17 Jun 2024
Mars' Methane Mystery: Earth's Qaidam Basin Offers Clues!
Earth is a habitable planet with a rich history of life evolving over approximately 4000 million years. The Earth's atmosphere contains around 1.8 parts per million of methane, with 71% originating from biogenic origin. Methane is therefore considered to be the first sign of life on a planet.
Since the first discovery of atmospheric methane on Mars in 2004, it has garnered significant attention as a potential sign of life on Mars. However, due to its extremely low concentration and strong fluctuation levels, its source and route into the Martian atmosphere are still unclear. More than 400 articles have been published on the subject since 2004, including 19 in Nature and 18 in Science, but there is still no indication of its origin.
Recognising its great importance in understanding the origin of life on Mars, both European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) have prioritised research into the Martian methane in their recent Mars exploration missions. Specifically, ESA has launched ExoMars, a satellite orbiting Mars to monitor atmospheric methane on Mars.
ESA’s recent exploration of methane on Mars. (Credit ESA).
In recent years, Professor Yiliang Li’s research group at the Department of Earth Sciences, The University of Hong Kong (HKU) has been exploring the Qaidam Basin on the Tibetan Plateau, as their research over the past decade has shown that the basin is one of the best analogs to Mars. Surprisingly, they discovered gypsum, a mineral found abundantly in the evaporation basins on both Earth and Mars, trapping methane gas bubbles in the crystals. Using various research tools, including spectroscopy and stable isotope compositions, they demonstrated that methane gas escapes from deep basins due to the internal pressure created by the tectonic movements of the salt. This finding suggests that Mars' atmospheric methane may have a similar geological origin involving minerals, evaporative basins, and hyper-arid climates.
The parallels between Earth’s Qaidam Basin and Mars offer intriguing insights into the potential origins of Martian methane, furthering our quest to understand the Red Planet's past and potential for life.
NASA’s current view of the potential origin of the atmospheric methane on Mars. (Credit: NASA/JPL-Caltech, SAM/GSFC)
The journal paper can be accessed here.