D MAGNETIC MODEL OF THE EARTH’S CRUST OF THE WHITE SEA AND ADJACENT TERRITORIES

An important task for the White Sea region, Russia’s second largest diamond-producing province, is the search for magmatic bodies overlapped by sedimentary cover via magnetometer survey. The models, linking local and magnetic anomalies with their sources, are essential for interpretation of search results. The aim of the study is to build a 3D magnetic model of the Earth’s crust for the White Sea region using aeromagnetic data and the modeling technologies of the Integro software package. The simulation is basing on a digital map of the pole-reduced anomalous magnetic field. The sources of magnetic anomalies are believed to be located in the Earth’s crust. The researchers obtained 3D distribution of the relative magnetic susceptibility of rocks by solving the inverse problem of magnetic prospecting. To separate the magnetic sources by spatial frequencies and depth, the model magnetic field was recalculated upward, as well as the TDR derivatives, which determine the lateral boundaries of the sources of positive magnetic field anomalies, were calculated. The researchers further analyzed 2D distributions of the magnetic sources of the model for vertical and horizontal sections with depths of 10, 15 and 20 km, thus proving the relationship between the surface and deep structures of the magnetic sources of the Earth’s crust in the region.

Blokh Yu. I. Interpreting gravity and magnetic anomalies. Moscow, 2009, 231 р. Available at: https://docplayer.ru/26469267-Yu-i-bloh-versiya-1-0.html. (In Russian).

2.    Starostenko V. I., Shuman V. N., Ivashenko I. N., Legostaeva O. V., Savchenko A. S., Skrinik O. Ya. Magnetic fields of 3-D anisotropic bodies: Theory and practice of calculations. Izv. Phys. Solid Earth, 2009, vol. 45, pp. 640—655. DOI: 10.1134/S1069351309080047.

3.    Baluev А. S., Brusilovsky Yu. В., Ivanenko А. N. Crustal structure of the Onega-Kandalaksha paleorift based on combined analysis of the White Sea’s anomalous magnetic field. Geodinamika i tektonofizika, 2018, vol. 9, iss. 4, рр. 1293—1312. Available at: https://doi.org/10.5800/GT-2018-9-4-0396. (In Russian).

4.    Cheremisina Е. N., Finkelstein М. Ya., Lyubimova А. V. GIS INTEGRO — import substitution software for geological and geophysical tasks. Geoinformatika, 2018, no. 3, рр. 8—17. (In Russian).

5.    Sharov N. V., Bakunovich L. I., Belashev B. Z., Zhuravlev А. V., Nilov М. Yu. Geologo-geophysical models of the earth crust of the White Sea Region. Geodinamika i tektonofizika, 2020, vol. 11, iss. 3, рр. 566—582. DOI: 10.5800/GT-2020-11-3-0491. (In Russian).

6.    Sharov N. V., Bakunovich L. I., Belashev B. Z., Nilov М. Yu. Velocity structure and density inhomogeneities of the White Sea crust. Arktika: ekologiya i ekonomika. [Arctic: Ecology and Economy], 2020, no. 4 (40), рр. 43—53. DOI: 10.25283/2223-4594-2020-4-43-53. (In Russian).

7.    Anomalous magnetic field map. Scale: 1:1 000 000 Q-(35), 36. Ed. Yu. V. Aslamov. WIRG-Rudgeophysics. St. Petersburg, 1999. (In Russian).

8.    Anomalous magnetic field map. Scale: 1:1 000 000 Q-37, 38. Ed. Yu. V. Aslamov. WIRG-Rudgeophysics. St. Petersburg, 2000. (In Russian).

9.    State geological map of the Russian Federation. Scale 1:1 000 000. Baltic Series. Sheet Q-35, 36 (Apatity). Explanatory note. 2009. 487 p. Sheet Q-37 (Arkhangelsk). Explanatory note. 2009. 338 p. Mezen Series. Sheet Q-38 (Mezen). Explanatory note 2009 p. 350 p. St. Petersburg, VSEGEI, 2009. (In Russian).

10. Petrophysical maps of geological formations in the eastern Baltic Shield (petrodensity and petromagnetic). Explanatory note to 1:1 000 000 scale maps, Science editor N. B. Dortman. Leningrad, 1980. (In Russian).

11. Tsybulya L. А., Levashkevich V. G. Thermal field of the Barents Sea Region. Apatity, KSC, RAS, 1992, 115 p. (In Russian).

12. Map of faults in the USSR and adjacent countries. Scale: 1:2 500 000. Chief Editor А. V. Sidorenko. Leningrad, VSEGEI, 1978. (In Russian).

13. Baluev А. S., Zhuravlev V. А., Terekhov А. N., Przhiyalgovsky Е. S. Tectonics of the White Sea and adjacent areas (Explanatory note to a 1:500 000 scale Tectonic Map of the White Sea and Adjacent Areas). Moscow, GEOS, 2012, 104 p. (In Russian).

14. Kimbell G. S., Stone P. Crustal magnetization variations across the Iapetus Suture Zone. Geological Mag., 1995, 132, pp. 599—609.

15. Wasilewski P. J., Mayhew M. A. The Moho as a magnetic boundary revisited. Geophysical Research Letters, 1992, vol. 19, pp. 2259—2262.

16. Pashkevich I. K., Sharov N. V., Savchenko А. S., Starostenko V. I. 3D geologo-geophysical lithospheric model of the central Karelian Craton. Geofiz. Zhurn., 2014, vol. 36, no. 6, рр. 58—78. (In Russian).

17. Merkulov V. P., Orekhov А. N., Volkova А., Korovin М. О. Developing a technology for prospecting potentially productive units in the rocks of a pre-Jurassic complex, Tomsk Region. 3D modelling of gravity and magnetic fields. Petroleum Learning Center. Heriot Watt university. Tomsk Polytechnical University, 2019. Available at: https://depnedra.tomsk.gov.ru/uploads/ckfinder/277/userfiles/files/1045.pdf. (In Russian).

18. Priezzhev I. I. Constructing the distribution of the physical parameters of the medium on the basis of gravity prospecting and magnetometry. Geofizika, 2005, no. 3, рр. 46—51. (In Russian).

19. Category GIS “Integro” User Guide. Available at: https://integro.ru/dl/ingeo/docs/. (In Russian).

20.  Miller H. G., Singh V. Potential field tilt—a new concept for location of potential field sources. J. of Applied Geophysics, 1994, vol. 32, pp. 213—217.

21. Beamish D., Kimbell G., Pharaoh T. The deep crustal magnetic structure of Britain. Proceedings of the Geologists’Association, 2016, vol. 127, pp. 647—663.

22. Golubev Yu. K., Vaganov V. I., Prusakova N. А. Principles of forecasting diamond prospects in the East European Platform. Rudy i metally, 2005, no. 1, рр. 55—70. (In Russian).

23.  Krutikhovskaya Z. А. Deep-seated magnetic heterogeneities: a myth or reality? Geofiz. Zhurn., 1986, vol. 8, no. 5, рр. 3—23. (In Russian).