Developing a Natural hydrogen play in the Transvaal basin of South Africa
PresentationWhat is happening in the H2 World - Part 2
2025-11-13 | 11:15 AM - 11:30 AM | Main Stage
Abstract
H2Au, working in collaboration with the NHSG, is advancing a play-based exploration strategy for natural hydrogen in cratonic terrains. Our approach draws on the Bourakebougou discovery in Mali, where hydrogen generation is attributed to the serpentinization of ultramafic rocks, meteoric recharge through deep fault systems, and entrapment beneath Proterozoic sedimentary cover. We apply this model to the Kaapvaal Craton of South Africa, a geologically stable Archean block with well-preserved greenstone belts and a substantial Proterozoic basin cover.
Following regional screening, H2Au has secured three Technical Cooperation Permits (TCPs) in the Transvaal Basin. The basin contains sequences of the 2.6–2.1 Ga Transvaal Supergroup, underlain by Archean granite-greenstone basement and intruded by the 2.06 Ga Bushveld Igneous Complex (BIC). Protoliths are recognized in ultramafic rocks forming part of greenstones and the BIC. The Murchison and Pietersburg greenstone belts occur along the northeast margin of the Transvaal Basin. The extension of greenstones under the basin is corroborated by greenstone remnants occurring in basement inliers inside the basin including the Dennilton Dome and Johannesburg Dome.
Ultramafic protoliths include komatiites, peridotites, dunites, and harzburgites within the greenstone belts and the lower Rustenburg Layered Suite of the BIC. These units offer favorable mineralogical compositions for hydrogen generation under the right conditions. The hydrogen potential of greenstone and BIC protoliths has been evaluated by Hy-Eval™, a geochemical modelling routine developed by NHSG and applied by H2Au.
Structurally, several major faults are developed in the Transvaal Basin/BIC including the NW-SE Rustenburg and Crocodile River Faults in the western BIC and the NE-SW Wonderkop and Steelpoort Faults in the east. The Thabazimbi-Murchison Lineament (TML) comprises a transcontinental strike-slip fault zone with reactivation, including recent seismicity.
The Malmani Fm dolomites of the Chuniespoort Group (of the Transvaal Supergroup) are an important aquifer in South Africa. Primary porosity and permeability are low due to alteration/re-crystallization but secondary porosity is reported in karstified sections. Potential paleo-karstification events are recognized pre-Pretoria Group, pre-BIC emplacement and pre- and post-Karoo.
Seals for the Malmani dolomites are provided by the ironstones of the Penge Fm (upper Chuniespoort Gp) and the thick shales of the Timeball Hill Fm of the Pretoria Group. It is expected that the sealing capabilities of the Pretoria Group will be have been enhanced by the effects of contact metamorphism from the overlying BIC.
Structural traps have formed by multiple deformational affecting the Transvaal Basin. Structures have formed pre-, syn- and post-BIC emplacement related to the effects of the Limpopo Orogeny to the north of the Kaapvaal Craton. Legacy seismic lines and geological mapping have been used to identify favorable closures.
The integration of basement mineral systems, active fault architecture, and stratigraphic trapping potential supports the presence of an active hydrogen system in the Transvaal Basin. Hydrogen observations in deep South African mines provide empirical support for ongoing subsurface generation. Exploration efforts will now focus on target refinement and the application of low-cost detection methods to test this first-mover hydrogen province.
