Analogue modelling of inverted domino-style basement fault systems
Inversion of pre-existing extensional fault systems is common in rift systems, back-arc basins and passive margins. It can significantly influence the development of structural traps in hydrocarbon basins. The analogue models of domino-style basement fault systems shown in this paper produced, on extension, characteristic hangingwall growth stratal wedges that, when contracted and inverted, formed classic inversion harpoon geometries and asymmetric hangingwall contractional faultpropagation folds. Segmented footwall shortcut faults formed as the basement faults were progressively back-rotated and steepened. The pre-existing extensional fault architectures, basement fault geometries and the relative hangingwall and footwall block rotations exerted fundamental controls on the inversion styles. Digital image correlation (DIC) strain monitoring illustrated complex vertical fault segmentation and linkage during inversion as the major faults were reactivated and strain was progressively transferred onto footwall shortcut faults. Hangingwall deformation during inversion was dominated by significant back-rotation as the inversion progressed. The mechanical stratigraphy of the cover sequences strongly influenced the fold and fault evolution of the reactivated fault systems. The implications of the experimental results for the interpretation and analysis of inversion structures are discussed and are compared with natural examples of inverted basement-involved extensional faults observed in seismic datasets.