Ground magnetic surveying
The Earth’s magnetic field is the result of current flow in the liquid outer core. Magnetisation in the upper crust results in small scale perturbations in the global magnetic field. These magnetic perturbations associated with varying magnetisation of rock units can be exploited to aid exploration by providing bedrock and structural information, regolith features and direct detection of magnetic ore bodies.
The magnetic field is measured by using a ‘magnetometer’. Magnetic surveys can be carried out on the ground, at sea or from the air. Ground magnetic surveys can acquire data with a high magnetic and spatial resolution but are time-consuming and difficult in rugged terrain or dense vegetation. Airborne magnetic surveying, or aeromagnetic surveying, is much faster but the resolution is determined by the flight height and line spacing. Modern surveys continuously sample the magnetic field along a survey line, typically providing a reading every 0.5 m to 10 m depending on sample rate and velocity of the sensor.
Data acquired along many survey lines can be ‘gridded’ and processed to produced plan images of the magnetic field within a project area. An interpretation of these images can provide valuable structural and bedrock information within a project area.
Anomalous magnetic responses can be modelled to provide representations of the source that may have produced the magnetic response. The result of this modelling can greatly assist drill targeting.
Resource Potentials own several very sensitive ground magnetometers that they use to carry out detailed ground magnetic surveys or rent to clients who would like to carry out their own ground surveys. Resource Potentials staff can provide ground magnetic training to clients who would like to carry out their own surveys.
If you are considering carrying out a magnetic survey and require assistance designing the survey, or already have magnetic data and would like to discuss processing, modelling or interpreting the data, please feel free to contact us.