Magnetic prospecting maps variations in the magnetic field of the earth that are attributable to changes of structure, magnetic susceptibility, or remanence in certain near-surface rocks. Sedimentary rocks generally have a very small susceptibility compared with igneous or metamorphic rocks, which tend to have a much higher magnetite content.
In mining exploration, magnetic methods are employed for direct location of ores containing magnetic minerals such as magnetite. Intrusive bodies such as dike can often be distinguished on the basis of magnetic observations alone.
Magnetic investigations found a wide application in engineering geophysics where are used primarily for the detection of ferrous materials buried near surface – pipes, cables, unexploded bombs (UXO), containers etc.
Applications of magnetism:
- Mapping geological boundaries
- Identification of fractures in the bedrock
- Mineral Exploration
- Geological mapping
- Detection of septic systems
- Detection of buried tanks
- Detection of buried weapons (UXO)
- Delimitation disposition pits / trenches
- Buried fuel tanks
- Detection of cables and pipelines
- Old settlements
- Old fields
- Historic structures
- Historical complex
- Observation posts
- Archaeological battlefields
- Search anchors dragline excavators, etc.
- Submerged tanks and landfills