Paleomagnetism, Geochronology, and Magnetic Mineralogy
of Devonian Dikes from the Kola Alkaline Province
(NE Fennoscandian Shield)

R. V. Veselovskiy^a,b, A. A. Arzamastsev^c, L. I. Demina^a, A. V. Travin^d, and S. B. Botsyun^a

^a Faculty of Geology, Moscow State University, Moscow, 119991 Russia

e-mail: roman.veselovskiy@ya.ru

^b Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, ul. B. Gruzinskaya 10, Moscow, 123995 Russia

^c Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences,
nab. Makarova 2, St Petersburg, 199034 Russia

e-mail: arzamas@ipgg.ru

^d Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences,
pr. Akad. Koptyuga 3, Novosibirsk, 630090 Russia

e-mail: travin@igm.nsc.ru

Received May 16, 2012; in final form, December 12, 2012

Abstract—The new paleomagnetic data on forty dikes and two intrusive plutons of Devonian age located in
different parts of the Kola Peninsula, which have not been previously covered by systematic paleomagnetic
studies, are reported. We describe the results of the rock magnetic, petrographic, and microprobe investigations
of the Devonian dikes and present their isotopic ages (⁴⁰Ar/³⁹Ar, stepwise heating). Within the studied area,
almost all the Devonian dikes, metamorphic Archaean–Proterozoic complexes of the Fennoscandian Shield,
and Proterozoic dikes have undergone low-temperature hydrothermal–metasomatic alteration, which resulted
in the formation of new magnetic minerals with a secondary (chemical) component of magnetization. The com-
parison of the paleomagnetic poles indicates the Early Jurassic age of the secondary component. We suggest
that regional remagnetization event was caused by endogenic activity genetically related to the formation of the
Barents Sea trap province 200–170 Ma ago. On the basis of the obtained data, the preliminary Devonian pale-
omagnetic pole of the East European Platform is determined.

Keywords: paleomagnetism, geochronology, rock magnetism, Kola Peninsula, Devonian, magmatic province,
dikes, remagnetization, isotopic age, ⁴⁰Ar/³⁹Ar dating

DOI: 10.1134/S106935131303018X

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