Magnetics

Aeromagnetic data measures variations in the Earth’s magnetic field caused by variations in the magnetic susceptibility of the underlying rocks.  It provides information on the structure and composition of magnetic basement and intrasedimentary magnetic units, if present.  Most bodies within the basement have a distinctive magnetic signature which is characterized by the magnitude, heterogeneity, and fabric of the magnetic signal.  When calibrated with known geology, magnetic data can be used to map basement terranes under a cover of sedimentary rock, regolith, water, or ice.

The most important and accurate information provided by magnetic data is the structural fabric of the basement.  Major basement structures can be interpreted from consistent discontinuities and/or pattern breaks in the magnetic fabric.  Once the structures have been evaluated and combined with those interpreted from gravity data, a model for the evolution of the basement and overlying basins can be developed.

Where the source of the magnetic signal is very deep and not resolvable after standard data processing, enhancement techniques are applied that  reveal information on the geometry and structure of the basement at depth.  Enhancement processing techniques are chosen specifically for each magnetic dataset depending on the type of information that needs to be extracted.  Enhancement processing is critical for evaluating deep basins.

Magnetic data is also valuable for determining the distribution of magnetic sources within the sediments ranging from heavy mineral deposits (e.g. fans) to basalts.