صفيحة أمريكا الشمالية
It is generally accepted that a piece of the North American Plate was broken off and transported north as the East Pacific Rise propagated northward, creating the Gulf of California. However, it is as yet unclear whether the oceanic crust between the Rise the mainland coast of Mexico is actually a new plate beginning to converge with the North American Plate, consistent with the standard model of rift zone spreading centers generally.