<P> The boundary along the Gulf of California is complex . The Gulf is underlain by the Gulf of California Rift Zone, a series of rift basins and transform fault segments between the northern end of the East Pacific Rise in the mouth of the gulf to the San Andreas Fault system in the vicinity of the Salton Trough rift / Brawley seismic zone . </P> <P> 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 east of the Rise and west of 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 . </P> <P> A few hotspots are thought to exist below the North American Plate . The most notable hotspots are the Yellowstone (Wyoming), Raton (New Mexico), and Anahim (British Columbia) hotspots . These are thought to be caused by a narrow stream of hot mantle convecting up from the Earth's core - mantle boundary called a mantle plume, although some geologists think that upper - mantle convection is a more likely cause . The Yellowstone and Anahim hotspots are thought to have first arrived during the Miocene period and are still geologically active, creating earthquakes and volcanoes . The Yellowstone hotspot is most notable for the Yellowstone Caldera and the many calderas that lie in the Snake River Plain while the Anahim hotspot is most notable for the Anahim Volcanic Belt, currently found in the Nazko Cone area . </P> <P> For the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge . </P>

What type of plate boundary is north america