Magnetic fabric of Devonian and Precambrian dikes from the northeastern Kola Peninsula, Russia

Nowadays, anisotropy of magnetic susceptibility (AMS) is a very widespread method to investigate the magnetic fabric of the rocks. AMS studies provide the information on the magma flow during formation of intrusives (dikes and sills) based on the orientation of the AMS ellipsoid. In this work we present the results of the AMS measurements of Devonian, Paleoproterozoic and Neoarchean dikes, which are located on the northeastern part of the Kola Peninsula. We use these data to reconstruct the direction of magma flow with the final aim to reconstruct the spatial distribution of the magma sources.

Laboratory studies of AMS were carried out on 1282 samples representing 102 dikes. At this stage, all studied dikes were typified based on their geological age and type of AMS (normal, reversed, intermediate). It is shown that not all the studied intrusive bodies retained the primary magnetic fabric and only a few of them can be used to reconstruct the position of magmatic centers and are promising for obtaining reliable paleomagnetic data. We also present the first results of interpretation of the direction of the magma flow during dike swarms forming.

The study is supported by the grant of RSF #16-17-10260.