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 The Frasnian–Famennian Virgin Hills Formation represents fore-reef facies deposited as part of the extensive Late Devonian reef system that fringed the SW Kimberley Block in Western Australia. It contains a rich trilobite fauna dominated primarily by proetids and, to a lesser extent, harpetids, phacopids, scutelluids and odontopleurids. To date, 49 taxa have been described, 40 of these being restricted to the Frasnian. Herein five Frasnian taxa are described, three in open nomenclature, and two the new species Telopeltis intermedia and Otarion fugitivum . Evolutionary trends in the Virgin Hills trilobites are dominated by a reduction in body size and eye size and, to a lesser extent, a reduction in exoskeletal vaulting. Although recording no sedimentological signature, the fauna was strongly affected by the two globally recognized Kellwasser extinction events. The first, at the end of conodont Zone 12, affected taxa at the species and genus level. The second, within Zone 13b, had a much greater impact on the fauna, causing extinctions at the familial and ordinal levels. Evidence is presented to suggest that evolutionary trends in the trilobites during the late Frasnian reflect selection for forms adapted to low nutrient conditions. The two intensive Kellwasser extinction episodes may reflect periodic massive inputs of nutrients from the terrestrial into the shallow-marine environment.