Aeromagnetic
Surveys
An aeromagnetic survey is a type of airborne
geophysical survey in which an aircraft is outfitted with a magnetometer to map
changes in the Earth's magnetic field. The
aircraft flies in a grid-like pattern over the survey area, and data resolution
can be increased by lowering the flying height and decreasing the line
spacing. The principle is similar to ground
magnetic surveys, but with the advantage of being able to map larger areas much
more quickly.
The magnetic data acquired is a measure of the
total intensity of the Earth's magnetic field at each recorded data point in
flight. Each data point is a combination
of the regional magnetic field generated in the Earth as well as tiny
variations due to constantly changing solar wind, the magnetic effects of the aircraft,
and magnetic features on the ground and subsurface. By subtracting these solar, regional and
aircraft effects, the resultant aeromagnetic data shows the relative abundance
of magnetic minerals and their spatial distribution in the upper levels of the
Earth's crust. Magnetite is the most
common magnetic mineral, and the content of magnetic minerals will vary in different
rock types. Therefore by analyzing the
aeromagnetic data, the geological structure of the upper crust can be interpreted,
including spatial geometry of rock units and structural features such as contacts,
faults and folds.
Fixed-wing airplanes are usually used for large
aeromagnetic surveys in gentle terrain, while helicopters or drones can be used
for more detailed surveys and/or in rugged terrain.
Aeromagnetic surveys are commonly used for mineral
exploration and can also be used for petroleum exploration. Aeromagnetic data can also be used to find
buried fault zones that are prone to damaging earthquakes, or to find
unexploded ordnance.
Specialists in Aeromagnetic Surveys
Terraquest was established in 1984 and since then, our dedicated team has flown over 1,500 airborne geophysical surveys using both fixed wing and helicopter platforms. Our professional crews provide significant experience having carried out airborne magnetic, gravity, gamma ray spectrometry, and electromagnetics on five continents. Our quality data sets have been utilized in the exploration for base and precious metals, kimberlite, hydrocarbons, uranium, rare earth minerals and water. The company has performed exemplary surveys for both small and large exploration groups as well as many government agencies. References can be provided upon request.
Visit www.terraquest.ca.