Magnetotelluric profiles in the McArthur Basin of Northern Australia
Authors / CoAuthors
Magnetotelluric techniques have been used to investigate structural trends in the McArthur Basin . Observations were made at 34 sites, extending 450 km across the Wearyan Shelf, the Batten Fault Zone, and the Bauhinia Shelf. For sites on the Wearyan Shelf, the orthogonal components of resistivity are generally similar, suggesting continuous horizontal strata and uniform basement depths. However, lateral changes in resistivity, evident on the Bauhinia Shelf, become extreme in the Batten Trough. For sites near the Emu Fault, the two components diverge at long periods, indicating a major change in structure with a pronounced vertical contact. Resistivities associated with the Tawallah Group appear distinct enough to show that no appreciable thickness of McArthur Group can be present east of the Emu Fault. The data are consistent with geological models based on the assumption that the Batten Trough formed as a syndepositional graben with rapid changes in depositional thickness at the boundary faults.