COSMIC RADIATION. “Life could evolve a variety of mechanisms to utilize such a large range of energy injected underground. It could produce molecular hydrogen and oxidants useful for life. Muons can both directly react with molecules present in the medium, and also indirectly through radiolysis products. A detailed description of all the chemical reactions including the intermediate steps can be found elsewhere.”
https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459