85 The Power of Hard Rocks: Driving the Energy Transition and Serving Society

This session examines how mafic and ultramafic rocks contribute to the energy transition by 1) generating hydrogen gas, 2) trapping CO2 through carbon mineralization, and 3) providing critical minerals for climate change mitigation and renewable energy production.

Monday, 20 October 2025
8:00 AM - 11:30 AM
HBGCC, 216AB

Experimental Quantification of the Hydrogen Production Potential of a Silica Undersaturated Basalt From Central Texas

Paper number: 85-9
Program: Technical Sessions
Time: 10:20 AM – 10:35 AM

Authors

Abstract

Mafic rocks are considered valuable resources in the energy transition due to their potential for carbon mineralization. Most recently, their role in abiotic hydrogen (H2) generation via water-rock interactions has also been proposed; however, the reaction pathway(s) for hydrogen generation remain poorly understood. Compared to ultramafic rocks, which are an important H2-producing lithology, mafic rocks have a more diverse mineralogy that may include feldspars and amphiboles. These additional silica-bearing phases may result in different reaction pathways that may drive H₂ production compared to ultramafic rocks. This study evaluates the H2 generation potential of Late Cretaceous silica undersaturated basalt from the Knippa Quarry, which is part of the Balcones Igneous Province in Central Texas. 

Detailed water-rock experiments were conducted to assess the H2 generation potential of this basalt. We placed millimeter-sized rock fragments in 160 mL Teflon-lined Hastelloy reactors at elevated pressure (170 psi) and temperature (90°C), using both Ar- and CO2-saturated water. The effect of NiCl2, a potential soluble reaction catalyst was also tested. Mineralogical and chemical changes as a result of rock-water-gas interactions were quantified using optical microscopy, X-ray powder diffraction, scanning electron microscopy and Raman microspectroscopy. Headspace gas composition was analyzed via gas chromatography, and water chemistry was measured using pH meter, conductivity meter, and inductively coupled plasma mass spectrometry.  

After 133 reaction days, results show higher H2 yields in experiments with CO2-rich fluids than in Ar-purged water. The addition of NiCl2 further enhanced H2 production, demonstrating that it is catalyzing the oxidation of Fe-bearing minerals. In addition to H2 generation, a concurrent decrease in measured mols of headspace CO2 are interpreted as evidence of carbon mineralization. Collectively, these data demonstrate that silica undersaturated basalts, such as the Knippa basalt in central Texas, have the potential for both geologic H2 production and carbon sequestration. 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412279

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