Magnetotelluric (MT) measures the natural variations of the Earth' magnetic and electrical (telluric) fields. The Audio-Magnetotelluric method (AMT) samples signal frequencies in the range of 20k Hz down to ~1Hz and provides data pertaining to the upper few kilometres of the Earth' crust. Broadband MT (BBMT) measures frequencies ranging from ~400 Hz down to periods of ~5000 s, providing measures of the conductivity of the crust. AMT and BBMT data were acquired at 138 stations with an interval of 2.5-5.0 km along a 690 km transect extending from Four Ways to Longreach in the South-eastern Mount Isa region. Full-waveform time series data were acquired and processed into frequency-domain transfer functions. Remote reference was applied to eliminate uncorrelated noise. After quality assurance, processed data were exported to industry-standard EDI files containing site info, impedance tensor, apparent resistivity, phase and vertical transfer function.
Maintenance and Update Frequency: asNeeded
Statement: Geoscience Australia in partnership with State and Territory Geological Surveys has applied Magnetotelluric (MT) method to image AustraliaÂ¿s electrical conductivity structure since the last decade. MT data have been applied to understand the nature and depth of the overlying cover sequences, and to image the electrical architecture of the economically important crystalline basement.
As part of the Queensland GovernmentÂ¿s Greenfields 2020 program, Geoscience Australia and the Geological Survey of Queensland (GSQ) have undertaken the Mount Isa Geophysics Initiative program including seismic, magnetotelluric and airborne electromagnetic surveys. The aim is to investigate mineral and energy potential by improving understanding of regional sub-surface geology and cover thickness and character.