The Northern Atlas fold-and-thrust belt of Tunisia: structural style and hydrocarbon occurrences based on surface and subsurface data

Mohamed Sabri Arfaoui¹, Radhouane Khouni¹, Fetheddine Melki², Mohamed Ghanmi¹ & Fouad Zargouni^2
1Laboratoire Géosciences, Ressources Minérales, Energétiques et Environnement, Département de Géologie, FST, Université de Tunis El Manar, Tunis, Tunisie.
²Laboratoire de Géodynamique, Géonumérique et Géomatériaux (L3G), Département de Géologie, FST, Université de Tunis El Manar, Tunis, Tunisie.
Corresponding author e-mail: msarfaoui@gmail.com

The Northern Atlas Fold-and-Thrust Belt of Tunisia has undergone a complex tectonic evolution, transitioning from Triassic rifting to Tertiary-present-day compression driven by Africa-Eurasia convergence. This study investigates the geological and tectonic processes within the Northern Atlas Fold-and-Thrust Belt to enhance our understanding of its hydrocarbon potential within this frontier province. Stratigraphic frameworks constructed from detailed lithostratigraphic logs, provided a critical foundation for developing high-resolution structural cross-sections. A comprehensive structural analysis, integrating surface and subsurface datasets along multiple transects, revealed pronounced along-strike variations in structural style from the northern to southern segments of the analyzed belt. The synthesis of these cross-sections into a unified regional profile highlights a heterogeneous structural style characterised by three dominant structural elements: (1) salt diapirism, (2) shallow décollement horizons within the sedimentary cover, and (3) deep-seated thrust wedges rooted in the basement. This investigation offers significant insights into the Cretaceous-Paleogene petroleum system of the NAFTB, demonstrating that the timing, geometry, and style of deformation exert a profound influence on key factors such as trap formation, source rock maturation, reservoir quality, and seal integrity. These findings underscore the importance of integrating structural analyses to better assess the hydrocarbon potential of fold-and-thrust belts in analogous tectonic settings.

Northern Atlas fold-and-thrust belt, structural analysis and style, hydrocarbon potential, exploration challenges.