In-situ abiogenic methane synthesis from diamond and graphite under geologically relevant conditions

• DOI: 10.1038/s41467-021-26664-3
• Publication Date: 2021-11-04T11:37:43Z
• Authors: Miriam Peña-Alvarez; Alberto Vitale Br...; Mary-Ellen Donnelly; Mengnan Wang; Philip Dalladay-S...; Ross Howie; Eugene Gregoryanz
• Keywords: Abiogenic petroleum origin; Carbon fibers

Diamond and graphite are fundamental sources of carbon in the upper mantle, their reactivity with H2-rich fluids present at these depths may represent key to unravelling deep abiotic hydrocarbon formation. We demonstrate an unexpected high between carbons' most common allotropes, diamond graphite, hydrogen conditions comparable those Earth's mantle along subduction zone thermal gradients. Between 0.5-3 GPa temperatures as low 300 °C, reacts readily H2 yielding methane (CH4), whilst higher (500 °C above), additional light hydrocarbons such ethane (C2H6) emerge. These results suggest that interaction reduced minerals be efficient mechanism for producing mantle.