EVOLUTION OF TRIPLE JUNCTIONS

The simple geometric ideas of plate theory are extended to include some forms of plate evolution. The most important of these occurs where three plates meet. Such triple junctions are divided into two groups, stable and unstable, according to whether or not they can retain their geometry as the plates move. These ideas suggest an explanation for some of the major changes which have occurred in the North Pacific during the Tertiary. © 1969 Nature Publishing Group.