Geologists of NSU are Working in a Cage with Magnetic Vacuum

The head of the new laboratory is a Corresponding Member of the Russian Academy of Sciences, Dean of Geology and Geophysics Department at NSU and also a Member of the Institute of Petroleum Geology and Geophysics at Siberian Branch of the Russian Academy of Sciencies Valery Vernikovsky. It should be noted that today the entire lab personnel is a staff of NSU and the Institute of Petrolium Geology and Geophysics at the Siberian branch of the Russian Academy of Sciences.

“The new laboratory has not emerged out of nowhere”, said the professor of the General and Regional Geology Department at NSU Dmitry Metelkin. “A team of scientists, who study issues of geodynamics and paleomagnetism in the Arctic region, has been working for a long time. We are engaged in geotectonic reconstructions, trying to use paleomagnetic data in order not only to restore the relative position of the ancient continents and oceans, but also to recreate the shape of the Earth, the Arctic in particular, of hundreds of millions of years ago”.

It is rather surprising, but most of the laboratory premises are taken by... a Cage. The Cage contains the main measuring part of the cryogenic magnetometer and the computer system managing the entire process. The noise in the laboratory is so strong that one has to talk in a raised voice, like talking on the railway platform. According to scientists, the incessant hum from a buzzing pump, pumping liquid helium, becomes something ordinary very quickly.

“The Cage compensates for the Earth's magnetic field and also protects the inner space from the external magnetic field. We can say that there is almost the magnetic vacuum in the Cage”, said Dmitry Vasilyevich.

All these precautions, like the expensive Cage made in the UK on a by-order basis, are required to measure accurately a number of characteristics of the ancient geomagnetic field. Such measurements are recorded in rocks. For their work the scientists use samples collected in the Arctic during the field season.

The official opening of the laboratory was attended by the NSU Rector's Office, headed by the Professor Mikhail Fedoruk, and the Professor of the Skolkovo business school Andrey Volkov, the guest of honor. The geologists told about special aspects and future prospects of their work.

“The equipment installed in the laboratory is innovative by the world standards. The main work is being done on the cryogenic magnetometer, developed in the USA by 2G Enterprises”, Valeriy Vernikovsky said to guests, pointing to the unit at the center of the Cage. “This type of magnetometer has the highest measurement accuracy for such studies. It is about 160 such devices in the world. In Russia there are only four such magnetometers: in Moscow, Khabarovsk, Novosibirsk (the Institute of Petrolium Geology and Geophysics at the Siberian Branch of the Russian Academy of Sciences) and now in Novosibirsk State University”.

A rock sample is placed in the cryogenic magnetometer, where, in addition to measuring the remanent magnetization, it is subjected stepwise to an alternating magnetic field: first, of small value, then of more power increasingly. Thus, the scientists restore the characteristics of the magnetic field of the Earth, existed for millions of years ago, which depend on the location of the rock in the space. Consequently, they characterize paleogeographic position of the rock at the time of catching the magnetic signal.

“Paleomagnetism studies not modern, but the ancient magnetic field. The magnetic characteristics, obtained with simple formulas of spherical geometry during the laboratory experiments and measurements, are associated with the sample position in the space. As a result, this method allows us to find the precise latitude at which the magnetization was acquired. Thus, it becomes possible to restore the location of the rock millions of years ago”, said Dmitry Metelkin.

Being in the cryogenic magnetometer the sample loses gradually all magnetization acquired during its "life" in nature. It is demagnetized. A paleomagnetologist Nikolay Mikhaltsov, working at the laboratory of geodynamics and paleomagnetism of the Central and Eastern Arctic, has told that on average the step-by-step destruction of magnetization of the sample takes from 40 minutes to one and a half hour. The work of the magnetometer is observed by the operator, who assesses the data received at the computer screen and, if necessary, intervenes in the process (stopping or changing the set program).

“The improved technique and ultra-sensitive equipment in the laboratory allows us to work even with those rocks that were previously considered unsuitable for paleomagnetic studies. For example, limestones, which contain the minimum magnetic minerals and, thus, have really low magnetization. This fact makes the magnetization of limestones impossible to be measured by other devices”, - he said.

“Currently, the equipment of the laboratory allows us to work practically with any rocks. The laboratory has all the necessary prerequisites for successful work not only in the Arctic, but also in all other regions”, concluded Nikolay Mikhaltsov.

Dina Golubeva

Photos provided by Svetlana Kim and Anna Romanenko

Photos provided by Svetlana Kim and Anna Romanenko