Abstract An integrated interpretation of the east Kimberley, northern Western Australia was completed to determine mineral prospectivity, and was centred on a portion of a magnetotelluric (MT) survey conducted across the entire Kimberley Craton and surrounding orogens. A structural geophysical interpretation used potential field data, and was constrained by geological field observations, petrophysics, remote sensing and understanding of the tectonic history of the region. Potential field forward modelling located along the same survey traverse as the MT data allowed comparison between the two datasets and their interpretations revealing interesting features suggesting the presence of large-scale structures, the presence of mineralization deep in the crust, and where mineralization may be at or near the surface. The King River Fault is shown from both the MT inversion and potential field modelling as a crustal-scale, west-dipping structure, the footwall of which bounds the western side of a large resistive body. A conductive anomaly is also located on the hanging wall of the King River Fault. Our assessment suggests that graphitic rocks, most likely with some sulphide content, contribute to the strength of this anomaly, and highlights the potential of the east Kimberley to host graphite and base metal deposits.

Abstract Northern Honduras and its offshore area include an active transtensional margin separating the Caribbean and North American plates. We use deep-penetration seismic-reflection lines combined with gravity and magnetic data to describe two distinct structural domains in the Honduran offshore area: (1) an approximately 120 km-wide Honduran Borderlands (HB) adjacent to the Cayman Trough characterized by narrow rift basins controlled by basement-involving normal faults subparallel to the margin; and (2) the Nicaraguan Rise (NR), characterized by small-displacement normal faulting and sag-type basins influenced by Paleocene–Eocene shelf sedimentation beneath an Oligocene–Recent, approximately 1–2 km-thick carbonate platform. Thinning of continental crust from 25–30 km beneath the NR to 6–8 km beneath the oceanic Cayman Trough is attributed to an Oligocene–Recent phase of transtension. Five tectonostratigraphic phases established in the HB and NR include: (1) a Late Cretaceous uplift in the north and south-dipping thrusting related to the collision in the south, between the Chortis continental block and arc and oceanic plateau rocks of the Caribbean; (2) Eocene sag basins in the NR and minor extension in the HB; two phases (3) and (4) of accelerated extension (transtension) across the subsidence mainly of the HB; and (5) Pliocene–Recent minor fault activity in the HB and a stable carbonate platform in the NR.