Impacts of Pre-Existing Structural Fabrics on Fault Growth and Evolution During Multi-Phase Rifting: Case Study From the Central Browse Basin, North West Shelf of Australia

Abstract

In multi-phase rifts, pre-existing structural fabrics that are formed during earlier rifting stages can influence fault growth during later deformation. Successive extensional episodes cause pre-existing faults to reactivate, leading to the propagation of fault planes and/or generation of branching faults in surrounding strata. Pre-existing faults can also locally control geometries (e.g., fault bends) and distributions of subsequent faults by creating stress and strain perturbations without exhibiting observable fault displacements (i.e., structural inheritance). Constraining the evolution of faults in multi-phase rift basins is crucial for understanding how accommodation spaces form and pathways for subsurface fluids (e.g., water, hydrocarbons, magma) develop during active deformation. However, due to structural complexity and limitations in data availability and resolution, capturing detailed fault geometries in time and space remains challenging. This study focuses on the structural framework of the central Browse Basin, the Australian North West Shelf, which experienced repeated phases of rifting throughout the Mesozoic. Using multiple surveys of a high-quality 3D seismic reflection dataset, this study demonstrates how successive extensional episodes shaped fault geometries and hence the structural configuration of the central Browse Basin. Key findings include: (1) the development of distinct fault patterns such as zigzag, rhomboidal, arc-shaped and en echelon geometries through reactivations of pre-existing Permian–Triassic faults; (2) a rotation in extensional stress orientation after the Late Jurassic, resulting in the deepening of WNW–ESE striking grabens; and (3) quantification of fault growth histories revealing variations in displacement and periods of activity, including the cessation of some major faults by the Late Jurassic. These insights provide a detailed tectono-stratigraphic evolution model for the central Browse Basin and offer broader implications for understanding fault behaviour in multi-phase rift systems globally.