The history of the magnetic poles of the Earth

Let's touch another mystery of our planet. This is the secret of the geological past of the Earth, which left its traces; you just need to find and decipher them. And one of the ways to penetrate the long past times is to study the history of terrestrial magnetism. For example, the history of the magnetic poles of the Earth can shed bright light not only on the magnetic past of the Earth, but also on the geological changes that have occurred.

For example, the history of the magnetic poles of the Earth can shed bright light not only on the magnetic past of the Earth, but also on the geological changes that have occurred

It has been found that many rocks that make up the crust of the earth have residual magnetism. Its occurrence refers to the times when these rocks, erupted from the earth's interior, were in a heated state. Under the action of the earth’s magnetic field, they were magnetized. When cooled, the direction of this field is “fixed” in the substance and can be subsequently detected.

Other studies are also possible, i.e., the study of residual magnetism in various products of human hands from different eras. During the manufacture of such products, the magnetic minerals that are part of any clay, when the product was cooled, after firing, were magnetized and "frozen" in a certain state, corresponding to the direction of the earth’s magnetic field.

By comparing these data and methods for determining the age of certain terrestrial rocks or antique products, it is possible to establish which direction the earth's magnetic field had in some particular area of our planet in certain historical periods.

The geographic poles of the Earth - North and South - are not fixed in place, but travel on the surface of our planet. For example, the North Pole slowly describes a complex spiral line around a certain middle position, deviating now to one or the other side by several meters from it. There is also evidence that the North Pole has one more, a forward movement. Therefore, the question arises: where and when were the magnetic poles of the Earth located in the past and how did they move? All the important information on this subject can bring the study of the movements of the magnetic poles of our planet. After all, the magnetism of the Earth is closely connected with its rotation around its own axis. That is, in the liquid core of our planet, rotating with the Earth, provided there is a sufficient difference in the temperature of the equatorial and polar regions, a magnetic field arises, oriented along the axis of rotation. Thus, the proximity of geographic and magnetic poles is not accidental. Consequently, their movements in the past were also joint.

At the same time, a general analysis of the data indicates that in different geological epochs the magnetic poles of the Earth were located at different points on the earth's surface. Thus, it confirms the assumption of a number of scientists that in the history of our planet there was a shift of thermal belts and climatic zones.

Analysis of the magnetic properties of rocks allows us to establish the direction of the Earth’s magnetic field for the corresponding historical epoch, that is, the direction to the magnetic pole. The point of intersection of such directions found for two different points of the earth's surface, and indicate the location of the magnetic pole of the Earth.

However, a comparison of paleomagnetic data related to the Siberian and European platforms revealed significant discrepancies. The corresponding points of the magnetic poles were located in completely different regions of the globe. How can this mismatch be explained? Maybe in the past there was a large magnetic anomaly? However, calculations show that such an anomaly would have to have a huge length of at least one and a half thousand kilometers, which is highly unlikely.

It is known that the continents do not "stand still", but move slowly, as a result of which their mutual position and orientation gradually change over time. The movement is so slow that it is not possible to detect it with modern means of observation. But paleomagnetic data from distant epochs would have to reflect such movements. In particular, discrepancies in the data for the European and Siberian platforms could get a natural explanation, if in the past, in the period covered by paleomagnetic measurements, there was a gradual convergence of these platforms by about 4 thousand km.