Long-period magnetotelluric (MT) data were collected in the Yilgarn Craton, Western Australia, in a ~200 x 250 km grid that crosses parts of the heavily mineralised Eastern Goldfields Superterrane and parts of the adjacent, less mineralised Youanmi Terrane. Inversions of the data highlight several mid- to lower-crustal conductors, mainly in the Eastern Goldfields Superterrane, and a broad, north-south trending, lithospheric mantle conductor beneath the Youanmi Terrane. Interpretations of the mantle conductor show that the Youanmi Terrane lithospheric mantle must contain more hydrogen and/or metasomatic minerals than the Eastern Goldfields Superterrane. Interpretations of the crustal conductors suggest they can only reasonably be caused by graphite or sulfide minerals. The pattern of conductivity is consistent with models for mineralisation in the region in which fertile, metasomatised mantle was partially melted beneath the Eastern Goldfields Superterrane, with the resulting mineralising fluids and melts subsequently ascending to the crust.

Open-Access Online Publication: March 03, 2023