As tectonic drift is due to the flow of magma, the pattern of magma flow affects the arrangement of tectonic plates. A manifestation of such arrangement is found along the latitude of 66°N. There are exactly 30° in between the west coast of Iceland and the west coast of Greenland along that latitude. Also, from the Icelandic coast to the abyss of Norway there are also 30° along 66°N.
Coincidence? Sorry, no way! Not to be understood? Not acceptable, because we are obliged to understand things like that, screaming and kicking!
Looking a bit more carefully, you will see that there are 6° along 66°N from the Norwegian abyss to the Norwegian coast. Also, from the west coast point of Iceland, there are exactly 6° to the central magma division line of lower mantle. That logically means that from the central line to the coast of Norway along 66°N there ara exactly 30°. That means the coast of Norway at that point is directly above the main division line of large lower mantle cells (as each of them spans 30° from east to west).
One out of endless mysteries of magic magma!