Flanking‐Style Fault‐Related Folds and Their Hydrocarbon Significance: Insights From the Red Sea, Gulf of Suez and East African Rift Systems

ABSTRACT

Flanking‐style fault‐related folds, including drag folds, rollover anticlines, forced folds and fault‐propagation folds represent a class of deformation features that develop in extensional rift settings. The term ‘flanking‐style’ is applied as an analogy to describe localized layer deflection and drag geometries adjacent to major extensional normal faults, drawing conceptual similarities with classic meso‐scale flanking structures. They exhibit a variety of morphologies that serve as diagnostic tools for interpreting deformation style, kinematic direction and strain distribution. Their analysis enables reconstruction of tectonic histories and enhances our understanding of the sequence of deformational events in complex geological terrains. Here, we shift focus to outcrop‐ to basin‐scale fault‐related folds—that, akin to ductile flanking structures, develop by local flexure or bending of layers as a result of displacement being accommodated by cross‐cutting faulting. This conceptual link suggests a continuum of flanking deformation across different rheological regimes, with implications for interpreting structural styles across scales and tectonic settings. The current study explores surface and subsurface examples of flanking‐style fault‐related folds within Oligo‐Miocene rift systems, specifically the Red Sea, the Gulf of Suez and the East African Rift. Our analysis shows that flanking folds developed as: (1) normal dragging, (2) forced folding, (3) roll‐over along fault segments. These structures are of significant interest in hydrocarbon exploration due to their impact on reservoir architecture, hydrocarbon trapping and migration pathways. These case studies aim to improve structural interpretation in rift‐related settings and support more accurate hydrocarbon exploration strategies and energy resource development in highly promising, less explored hydrocarbon frontiers.