Aerial geophisical exploration
AERIAL GEOPHYSICAL EXPLORATION, aerial geophysical survey (EN: aerogeophysical exploration; DE: geophysikalische Luftaufnahme, Aerogeophysik; FR: prospection aerienne geophysique; ES: prospeccion geofisica aerea; RU: аэрогеофизическая разведка) is the set of the methods for the measurement of the natural or artificially excited physical fields of the Earth by the equipment, which has been installed onto the aircraft or helicopter (aerial gamma-ray survey, aerial magnetic survey, aerial electromagnetic exploration, and others).
The aerial geophysical exploration is used for the searches for the deposits of the useful minerals (oil and gas, ores of the non-ferrous metals, radioactive ores), and also for the tectonic zonation and geological mapping. The intensity of the physical fields decreases with distance from the surface of the Earth, the fields of the local ore bodies attenuate especially sharply. Because of this, the aerial geophysical exploration is performed at the relatively small (30-300 metres) constant height above the surface of the land or above the level of the sea. The scales of the surveys are from 1:10000 to 1:200000. Sometimes the aerial geophysical exploration (aerial magnetic, aerial gravimetric) is conducted at the smaller scales and at the height of 1-3 kilometres with the purpose of identification of the deep sources of anomalies.
The aerial geophisical exploration provides the greatest effect during the integrated usage of the data of several aerial geophysical stations, which permit to register several physical fields simultaneously, and to improve significantly the reliability of the searches for the ore bodies. For example, the deposits of the rare metal ores, bauxites and phosphorites, often distinguish themselves with the radioactive anomalies with the decreased level of the magnetic field. The copper-nickel ore bodies are characterized by the matching electrical and magnetic anomalies; above the pyritic ores, the magnetic anomalies are absent.
The aerial geophysical exploration is characterized by the great efficiency and effectiveness in comparison with the ground surface methods on the account of the rapidity and the possibility of the conducting of the works within any (including arduous) regions.
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