1,2,3,1,4,5,7,8- 1GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
- 2University of Lausanne, Lausanne, Switzerland (frank.zwaan@unil.ch)
- 3University of Fribourg, Fribourg, Switzerland
- 4University of Potsdam, Potsdam, Germany
- 5Tufts University, Medford, MA, USA
- 6New Mexico Institute of Mining and Technology, Socorro, NM, USA
- 7University of Strasbourg, CNRS, ENGEES, Strasbourg, France
- 8Lavoisier H2 Geoconsult, Chamonix, France
Natural hydrogen gas (H2) generated through the serpentinization of mantle rocks is a promising source of clean energy. For large-scale serpentinization and natural H2 generation to occur, the mantle rocks need to be brought into a optimal temperature range (the serpentinization window) and into contact with water. Alpine-style rift-inversion orogens, formed during the closure of rift basins, provide excellent environments for serpentinization-related natural H2 generation, while also harbouring extensive volumes of sediments in which natural H2 accumulation could form. In such orogens, erosion is known to have an important impact on exhumation processes and sediment distribution, but to what degree erosion efficiency influences natural H2 resource potential remains poorly understood. We use numerical geodynamic models of rift-inversion to explore and, importantly, quantify the relative roles of erosion and tectonic processes by applying different erosion efficiencies and initial rift phase durations.
Our modelling shows that, regardless of erosion efficiency, initial rift duration is a dominant factor during both the extension and inversion phase. Prolonged rifting causes increased mantle exhumation and thus higher natural H2 generation potential. Erosion efficiency exerts only a secondary effect, in that more efficient erosion modestly reduces H2 generation potential by narrowing the serpentinization window. Inversion of advanced rift basins results in asymmetric orogens in which mantle material is incorporated into the overriding wedge, a configuration that is critical for generating high natural H2 generation potential in these systems. Nevertheless, efficient erosion of otherwise symmetric orogens formed after limited rifting allows for a shift to an asymmetric style, with significant mantle exhumation and natural H2 generation potential.
However, efficient erosion and associated fast exhumation of relatively hot material in orogens can also decrease the vertical extent of the serpentinization window, reducing natural H2 generation potential. Moreover, rapid erosion can remove the otherwise abundant potential reservoir rocks and seals needed for exploitable natural H2 accumulations to form. Still, these negative effects of erosion on “conventional” natural H2 resources (involving H2 accumulation in reservoir rocks), may be favourable for “unconventional” natural H2 resources. Systems with relatively hot mantle material close to the surface may in fact be suitable for stimulated natural H2 exploitation efforts, involving direct drilling of the mantle source rock itself.
Thus, although erosion efficiency is not the dominant factor, it can still have a considerable impact on natural H2 potential in rift-inversion orogens. Therefore, a thorough understanding of the evolution of those orogens targeted for exploration, will be of great importance. This challenge can be aided by numerical geodynamic models such as those presented here, with which we perform a first-order analysis of natural examples from the Pyrenees, Alps, and Betics.
How to cite: Zwaan, F., Glerum, A. C., Brune, S., Vasey, D. A., Naliboff, J. B., Manatschal, G., and Gaucher, E. C.: The impact of erosion processes on natural H2 resource potential in Alpine-style orogens, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8255, https://doi.org/10.5194/egusphere-egu26-8255, 2026.
