Hydrocarbons to hydrogen in salt basins: outcrop analogue evidence for seal behaviour at Enorama Diapir, Ikara-Flinders Ranges National Park

Salt basins host many of the world’s most productive energy systems, yet predicting seal performance around salt bodies remains a key uncertainty. This has direct relevance for conventional hydrocarbon and hydrogen exploration, short- and long-term carbon dioxide (CO2) sequestration, and emerging clean energy storage projects. The unique physical and chemical properties of salt in the subsurface make it challenging to image through geophysical methods; thus, outcrop analogues provide valuable insight into the characteristics of salt strata for energy applications. This study utilises a globally significant outcrop analogue from the Enorama Diapir in South Australia’s Adelaide Rift Complex, where Precambrian salt movement directly influenced the development of a stromatolite reef and its surrounding seal system. Stretching across 8 km of exposure, this outcrop captures how salt rise controlled depositional architecture, generated topographic relief, and drove the distribution of carbonate and siliciclastic lithofacies. Stratigraphic logs, correlations, and lithofacies analysis enable an interpretation of the preserved stratigraphy, which documents cycles of salt movement, accommodation creation, and syntectonic sedimentation. Basin fill contains the deposits of debris flows, slumps, and turbidity currents sourced directly from the diapir, which interfinger with the surrounding deeper-water shale-siltstone seal. These features offer rare physical evidence of how seal formations evolve in response to active diapiric structures. The Enorama Diapir provides direct calibration data that can be used to reduce uncertainty in seal integrity assessments. Such insights are crucial for evaluating hydrocarbon and hydrogen traps. They are equally important for advancing the energy transition, particularly in improving risk prediction for salt-hosted hydrogen and carbon dioxide storage projects.