The Atlantic Ocean is the type example of a symmetrical spreading ocean, and the North Atlantic is the best example of two plates spreading
around a pole of rotation. All motions on a sphere can be represented as
rotation around a pole, but for most plate pairs, the mutual pole of rotation is
far away and often several plates away. The Eurasian and North American Plates,
in contrast, rotate around a pole in northeastern Siberia on the Eurasian Plate,
and the plate boundary changes from spreading to compressional near the pole.