What is an Aeromagnetic Survey?

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.


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