[Editor’s note: From a paper by Fabien Baron and three co-authors recently published in the Journal of Geophysical Research.]
New Constraints on Early Mars Weathering Conditions From an Experimental Approach on Crust Simulants
• Chemical weathering in mildly acidic conditions under a CO2 atmosphere yielded leaching of alkali and alkaline earth elements
• Mass balance calculations indicated Al, Fe, and Si enrichment in the weathering products
• Our results imply unsuitable conditions for carbonate formation despite CO2 in the Martian atmosphere
Mars orbital and landed missions have provided mineralogical, morphological, and field evidence for liquid water at the surface approximately 3.5 billion years ago. The chemical and mineralogical composition of the Martian rocks have potentially been modified by interaction with this liquid water.
The purpose of our study is to use laboratory experiments to constrain the physicochemical conditions of water resulting from the chemical weathering of Martian crust simulants under an atmosphere composed of carbon dioxide, as is the case for Mars. The water in contact with simulants is mildly acidic. The partitioning of chemical elements between the solution and minerals is similar to what is observed on Earth, but weathering is more intense.
Despite that Mars had a primitive CO2‐dense atmosphere, the conditions were not favorable to the extensive formation of carbonate at the surface. [More at link]