Formation of H2 and CH4 by weathering of olivine at temperatures between 30 and 70°C

The results show low temperature CH4 production that is probably influenced by chromite and magnetite as catalysts. Extensive analyses of a potential CH4 source trapped in the crystal structure of the olivine showed no signs of incorporated CH4. Also, the available sources of organic carbon were not enough to support the total amount of CH4 detected in our experiments. There was also a linear relationship between silica release into solution and the net CH4 accumulation into the incubation bottle headspaces suggesting that CH4 formation under these conditions could be a qualitative indicator of olivine dissolution.It is likely that minerals such as magnetite, chromite and other metal-rich minerals found on the olivine surface catalyze the formation of CH4, because of the low temperature of the system. This may expand the range of environments plausible for abiotic CH4 formation both on Earth and on other terrestrial bodies.The CH4 detected in the Martian atmosphere [1-3] in 2004 raised the question whether or not the CH4 were formed biotically or abiotically. It was suggested by Krasnopolsky et al. [3] that microorganisms on Mars may have produced it. However, several abiotic processes may be responsible for the detected atmospheric CH4, such as volcanism, exogenous sources and serpentinization of ultramafic rocks [4-6]. There are too few hot spots present on Mars to account for the CH4 concentrations that were detected and volcanism is not likely to be the major source of CH4 on Mars. Neither are the exogenous sources, such as meteorites and comets, for the same reason. Oze and Sharma [4] have calculated reaction rates for olivine dissolution on Mars, using olivine chemical compositions found in the Martian Schergottite-Nakhlite-Chassigny (SNC) meteorites, a temperature of 25°C and varying pH. They came to the conclusion that dissolution of olivine is favorable in the subsurface of Mars at such low temperatures, both kinetically and thermodynamically, which means t