Kursk Magnetic Anomaly
The Kursk Magnetic Anomaly (KMA; Russian Курская магнитная аномалия (КМА) ) is considered the world's largest local anomaly in the Earth's magnetic field .
General
The anomaly is an iron ore deposit-west of the European part of Russia caused. There are (estimated) 200 billion tons of iron ore with an average iron content between 35 and 60 percent stored underground in an area of more than 100,000 square kilometers in the Oblasts of Kursk , Belgorod and Orjol . As a result, the magnetic needle of the compass in this area is deflected from the otherwise usual north direction . The term Kursk Magnetic Anomaly has also been transferred to the iron ore deposit itself or the area underlain by it.
History of discovery and use
The anomaly was first described by the astronomer and member of the Russian Academy of Sciences Pyotr Inokhodzew in 1773 .
In 1874 the associate professor at the University of Kazan N. Smirnow began geomagnetic measurements and in 1883 the associate professor N. Pitschikow of the University of Kharkov for the first time predicted iron ore deposits as the cause of the anomaly.
Work in this direction was carried out in particular by the physicist at Moscow University Ernst Leist (1852-1918) until the First World War .
Detailed geological investigations were not carried out until the 1920s, led by a state commission under the geologist Iwan Gubkin .
The first iron ore was found on April 7, 1923 near the town of Shchigry at a depth of 167 meters, the first minable ore in 1931.
In 1935, the sample degradation began underground , promoting large scale in opencast mines , however, until the 1950s. The first enrichment factory started operations in 1956.
The largest open-cast mine today is Lebedinski near Gubkin with a depth of 350 meters (floor level about 150 meters below sea level), from which over a billion tons of iron ore have been extracted since 1971.
Individual evidence
- ↑ Patrick T. Taylor, Ralph RB von Frese, Hyung Rae Kim: Results of a comparison between Ørsted and Magsat anomaly fields over the region of Kursk magnetic anomaly (abstract) . In: Proceedings of the 3rd International ØRSTED Science Team Meeting . Danish Meteorological Institute. Pp. 47-50. 2003. Archived from the original on July 17, 2011.