Rift-inversion orogens are potential hot spots for natural H <sub>2</sub> generation
Frank Zwaan, Sascha Brune, Anne Glerum, Dylan A. Vasey, John Naliboff, Giänreto Manatschal, Éric C. Gaucher
Abstract
Naturally occurring hydrogen gas (H 2 ) represents a potential source of clean energy. A promising mechanism for large-scale natural H 2 generation is serpentinization of exhumed mantle material. We study this serpentinization-related H 2 generation during rifting and subsequent rift-inversion orogen development using numerical geodynamic models. Serpentinization-related H 2 generation is best known from rifted margins and spreading ridges. However, because orogens are colder than rift environments, conditions for serpentinization and natural H 2 generation are considerably better in orogenic settings: We find that yearly H 2 generation capacity from serpentinization in the overriding mantle wedge during rift inversion may be up to 20 times larger than during rifting. Moreover, suitable reservoirs and seals required for economic H 2 accumulations to form are readily available in rift-inversion orogens but are likely absent during bulk serpentinization in rift settings. Together with indications of ongoing natural H 2 generation in the Balkans and Pyrenees, our model results provide a first-order motivation for natural H 2 exploration in rift-inversion orogens.