Structural evolution of the inverted Neoproterozoic Yeneena Basin, Australia

Carbonaceous shales and carbonates within the Neoproterozoic Yeneena Basin in the Paterson Orogen, Western Australia are prospective for sulphide mineralisation, as exemplified by the Nifty copper deposit. However, the tectonic setting of basin formation, its present-day structural architecture, and the kinematic evolution associated with basin inversion remain ill-constrained due to limited exposure. We address this issue by integrating published geological and geophysical datasets with new structural measurements from drill cores, performing subsidence analysis, and constructing four regional-scale balanced cross-sections. Subsidence analysis of the Throssell Range Group reveals an initial phase of rapid subsidence consistent with syn -rift extension, followed by a progressive decrease in subsidence rates indicative of the sag phase. Basin inversion produced folds with predominantly NW-SE trending hinge lines, and systematic variations in bedding-cleavage angles relative to fold geometry indicate that folding occurred via buckling by the flexural shear mechanism. Structural relationships suggest that deformation initiated in the northeastern part of the basin, where sedimentary rocks and underlying basement were folded first, followed by the reactivation of basement normal faults as reverse faults that transected these folded structures. Deformation subsequently propagated southwestward across the basin. Restoration indicates the presence of horsts that segmented the basin into smaller subbasins. We estimated a minimum shortening of ∼ 11–21 km (19–30%) from the study area. Forward modelling demonstrates that folding was the dominant mechanism for accommodating shortening rather than reverse faulting. This study presents the first basin-scale structural reconstruction of the Yeneena Basin and offers new insights into its kinematic evolution.