Strike-Slip Fault Systems and Pull-Apart Basin Evolution

Strike-slip fault systems arise where lateral shear stress dominates, causing crustal blocks to slide past one another. Along such faults, bends and step-overs generate zones of transpression (compression) and transtension (extension). In transtensional segments, releasing bends or steps create pull-apart basins—elongated depressions bounded by en echelon fault segments and transfer faults. These basins typically exhibit half-graben profiles in cross section and rhombic or rhomboidal shapes in map view. Their evolution involves interaction between primary strike-slip faults, subsidiary Riedel shear fractures (R-shears), P-shears and T-faults, which control basin geometry, sediment infill patterns and fluid pathways. Globally, pull-apart basins play a pivotal role in hydrocarbon accumulation, groundwater storage and seismic hazard distribution. Advances in physical modelling, high-resolution seismic imaging and structural kinematic analysis have refined our understanding of fault segmentation, basin architecture and the timing of basin development under variable stress regimes. These insights inform exploration for oil and gas, groundwater resources and provide analogues for other continental and intracratonic settings.

Research from Nature Portfolio

Recent studies have employed scaled physical simulation experiments to examine the impact of basement strike-slip activity on sedimentary cover deformation and hydrocarbon accumulation in sag basins. By varying caprock thickness and shear strength, researchers traced the propagation of R-shear and P-shear faults into overlying strata and visualised dyed fluid migration. This work led to the formulation of multiple accumulation models—ranging from isolated channel fills to continuous belt aggregations—highlighting that intersections of R-shear and P-shear planes, and pressurised R-shear deformation zones, are prime target areas for fluid trapping. The experimental results underscore the importance of detailed fault-zone architecture in predicting reservoir distribution within pull-apart settings.

Strike-Slip Fault Systems and Pull-Apart Basin Evolution publication trend

The graph below shows the total number of articles in strike-slip fault systems and pull-apart basin evolution across all publications each year (not limited to Nature Index journals).

Technical terms

Strike-slip fault: A fracture in the crust where blocks move predominantly horizontally past each other.

Pull-apart basin: A depression formed in transtensional step-over zones of strike-slip faults, often filled by sedimentary and volcanic deposits.

Riedel shear (R-shear): A subsidiary fault that forms at a low angle to the main strike-slip fault, accommodating early shear deformation.

En echelon faults: A series of parallel, staggered fault segments that overlap or step over one another in map view.

Flower structure: A vertical fault zone geometry in cross section, fanning upward as positive (transpressional) or negative (transtensional) splays.

References

1. Effect of intensity of sedimentary cover deformation on hydrocarbon accumulation in Dongying Sag, Bohai Bay Basin, China. Scientific Reports (2024).
2. Reacquainting the Structural Characteristics of Pull-Apart Basins Based on Simulations with Wet Clay. Sustainability (2023).
3. Segmentation and lateral growth of intracratonic strike-slip faults in the northern Tarim Basin, NW China: influences on Ordovician fault-controlled carbonate reservoirs. Frontiers in Earth Science (2023).