Mount Isa magnetotelluric survey

Project date

2009

Description

As part of the Queensland Government's Smart Mining - Future Prosperity program, we conducted a tensor magnetotelluric (MT) survey in the Mount Isa region.

MT is an electromagnetic technique measuring naturally occurring electric (telluric) currents induced by variations in Earth's magnetic field to image the conductivity structure of Earth's crust to similar depths. These telluric currents are influenced by rock properties such as type, porosity, permeability and temperature.

Mount Isa magnetotelluric survey profiles

Figure 1: 3D image showing the network of magnetotelluric profiles in the Mount Isa region

Objective

The objective of the survey was to test how well the MT technique could penetrate conductive cover and resolve geological structures to a depth of 5km in various geological terranes.

Method

We used a dipole length of 100m and station intervals varying from 500m to 4km across different terranes. Data at each station was obtained over a 24-hour period, measuring a frequency bandwidth of between 0.001Hz and 250Hz.

Data was acquired at a total of 240 stations along seven profiles. Three profiles were coincident with, or adjacent to, deep crustal seismic data acquired by Geoscience Australia and the Geological Survey of Queensland (GSQ). The remaining 4 profiles were defined to help interpret the:

  • Millungera Basin region east of Quamby
  • Carters Bore region
  • area adjacent to the Ernest Henry mine—where data is being used to map regional geological structural elements.

Survey results

Find out how to order the data and logistics reports, modelled 2D resistivity depth inversions, a 3D inversion for the Millungera Basin area and an interpretative report.

Contact

General enquiries 13 QGOV (13 74 68)