RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 10, ES4003, doi:10.2205/2007ES000258, 2008

Introduction

[2]  Geomagnetic exploration has a long history. It started with a discovery of the "loadstone'' (a rock, rich in magnetite). Aristotle supposed that the first research of the characteristics of magnetite, that can be called scientific, was the work by Thales of Miletus (who lived on the territory of modern Turkey between VII and VI centuries B.C., though some scientists think that it was already known and applied in Egypt (but none of the Egyptian descriptions of it remained). The first literary record of magnetite in China refers to IV century B.C., and the first mention of a magnetized arrow being attracted by a loadstone was made in China between 20 and 100 A.D. But the idea that the Earth acts like a magnet appeared much later. In 1088 a polymathic Chinese scientist Shen Kuo in his book "Dream Pool Essays'' described the methods of improving navigation with the help of a compass and a notion of the "real'' (geographical) direction to the North. In Europe the first ideas about using a compass for naval navigation were published in 1187 by a British theologian and historian Alexander of Neckam.

[3]  In 1600, after a book by William Hilbert "About a magnet'', a follower of Giordano Bruno, telling about magnetic bodies and a big magnet - the Earth, with a positive commentary by Galileo Galilei, was published, ideas about the geomagnetic field, its direction and activity were provided with a scientific foundation. Systematic numerical observations of the direction of the Earth's magnetic field started in London at the lifetime of W. Hilbert [Sharma, 1989]. In Sweden already in 1640 the observations of local anomalies of the direction of the Earth's magnetic field were used for discovering iron ore deposits.

[4]  The sphere of application of magnetic methods, comprising the spheres of geomagnetism, rock magnetism, paleomagnetism, magnetic exploration, navigation on the basis of magnetometry, influence of the magnetic field on people's health, including crews of aircrafts, etc, are currently so wide, that it is impossible to cover all these aspects within the scope of one work. Moreover, by the present time the most impressive results of geomagnetic research are related to obtaining data on such thrilling phenomena, as the continental drift, spreading of the ocean floor, plate tectonics, movement of geographic and magnetic poles, etc. Paleomagnetic research produced the first grounds for the concept of mantle convection, underlying the notion of plate tectonics and rapidly developing during the last 15 years [Bird, 2003].

[5]  The strength of magnetic field is measured by satellites, airplanes, ships, observatories and is systematized, formed and recorded every 5 years since 1945. Less accurate (but systematized) data after each 5 years are available since 1900. Non-systematic observations were carried out considerably earlier. However, until the present time the visualized interpretation of data of the Earth's magnetic field as a whole is still insufficient, having in view the purpose of its reliable analysis and study for carrying out the further fundamental and applied research.

[6]  The work presents the cartographic method of interpretation of measurements of the geomagnetic field and of designing geographical charts of the Earth's main magnetic field and geoinformation system.


RJES

Citation: Zhalkovsky, Ye. A. (2008), Chart-making of the Earth's main magnetic field, Russ. J. Earth Sci., 10, ES4003, doi:10.2205/2007ES000258.

Copyright 2008 by the Russian Journal of Earth Sciences

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