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The interactions between salt diapirs, thrust welds and thrusts in contractional belts are poorly understood due to, first, the inability of seismic data to distinguish between thrusts and welds or resolve associated sub‐resolution deformation, and second, the paucity of good field examples. The Warraweena area in the Northern Flinders Ranges of South Australia contains examples of Neoproterozoic to Early Cambrian squeezed diapirs linked by steep reverse faults formed during the Delamerian Orogeny. Benefiting from good field exposures, we use geological mapping, cross‐section construction and conceptual structural models to assess the three‐dimensional geometry and evolution of the structures, the lateral transition from diapirs to linking faults and the variability of associated meso‐ and small‐scale deformation. Three discrete diapirs consist of narrow outcrops of Callanna Group megabreccia (Willouran in age) up to 5‐km long. Their diapiric origin is confirmed by local development of caprock, steepening of flanking strata in composite halokinetic sequences and reworked diapir and roof debris in adjacent strata. The surrounding rocks display only background levels of small‐scale deformation. In contrast, the linking faults show no evidence of precursor diapirism, have fault‐related anticlines up to 100s of m in wavelength in their hanging walls, and an associated increase in small‐scale deformation (i.e. millimetre to metre scale folds, fractures and shear fabrics). The transitions from diapirs to faults occur within less than 200 m as short thrust welds at the diapir terminations. The exposed structures are analogous to those found on the subsurface of other salt basins such as the Gulf of Mexico and the South Atlantic conjugate margins. The results of this work can aid geoscientists evaluating three‐way traps against squeezed diapirs, welds or faults, and can help them to predict the style and abundance of both halokinetic and small‐scale structures that are below seismic resolution. [ABSTRACT FROM AUTHOR]

Abstract We combine insights from subsurface studies and published numerical models to propose a three-phase conceptual model that considers the potential deformation patterns that form during the emplacement, evacuation and welding, and post-welding phases of tertiary weld formation. The proposed model aims to: 1) help establish the timing of deformation adjacent to a tertiary weld based on the geometry of deformation patterns, and 2) serve as a guide for future work that examines deformation adjacent to tertiary welds and beneath allochthonous salt. We apply the model, along with new, 1:10,000 scale geological mapping and mesostructural analysis of deformation patterns along the Kingston tertiary salt weld and contiguous Witchelina-Breaden Hill salt canopy in the Willouran Ranges of South Australia to constrain the evolution of the allochthonous salt system and the style, extent, and timing of adjacent deformation. Deformation near the weld is dominated by opening mode fractures that exhibit spatial heterogeneity in their orientation both along the strike of allochthonous salt and in suprasalt versus subsalt strata. A halokinetic drape fold, decimeter to decameter scale folding, and localized debris flow deposits are present in subsalt strata, whereas no evidence of thrust imbricates, or laterally continuous shear and/or rubble zones was observed anywhere below the canopy-weld complex. We hypothesize that remnant evaporite distribution and the juxtaposition of units exert the primary, largest-scale control on the hydrological behavior of tertiary welds. The influence of deformation occurs at a much smaller scale and is more heterogeneous and difficult to predict. Higher resolution models and additional field studies are required to identify and rank the many variables that control this deformation. Highlights • 1:10,000 scale field mapping and mesostructural analysis characterize a canopy-weld complex in the Willouran Ranges. • Tertiary welds evolve in three phases: (1) salt emplacement, (2) evacuation and welding, and (3) post-welding/reactivation. • The Kingston weld formed from the evacuation of a former salt canopy that was created when two sheets sutured together. • The weld has spatially varying brittle deformation patterns, which likely formed in the late welding or post-welding phase. • Spatially varying deformation is a critical, yet insufficiently understood, control on weld hydrological behavior. [ABSTRACT FROM AUTHOR]