A Systems-Based Integrated Workflow for Evaluating Thermogenic Gas and Natural Hydrogen Systems in a Fold-And-Thrust Belt: Insights from the Eastern Cordillera of Colombia

Thermogenic gas and natural hydrogen exploration in structurally complex fold-and-thrust belts requires integrated approaches capable of reducing geological uncertainty and constraining gas generation, migration, trapping, and preservation processes. This study presents a multidisciplinary workflow for characterization of potentially thermogenic gas and natural hydrogen systems in the Eastern Cordillera of Colombia, covering approximately 17,843 km2 across four regional transects. The workflow integrates geological mapping, stratigraphic and sedimentological analysis, in situ gas surveys, core characterization, multiparametric laboratory analyses, 2D seismic interpretation with structural restoration, and one-dimensional thermochronological modeling. Surface hydrogen anomalies with recorded values of up to 2000 ppm were identified, with the highest concentrations occurring in the Eastern Sector in areas associated with exposures of the Lower Cretaceous units. Geological and geochemical evidence indicates that Lower Cretaceous formations constitute the principal thermally mature source intervals, whereas Upper Cretaceous evaporites and Paleogene fine-grained units provide potential regional seals. Thermochronological reconstructions show that several structural domains entered the dry-gas generation window during the Late Oligocene–Early Miocene (~30–20 Ma), and their spatial correspondence with present-day hydrogen anomalies suggests fault-controlled migration from deep mature systems. The integrated analysis further enabled the identification of prospective exploration fairways for thermogenic gas and natural hydrogen. The proposed workflow provides a transferable framework for evaluating natural hydrogen and thermogenic gas systems in inverted sedimentary basins worldwide.