North American Plate
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The North American Plate is a tectonic plate covering most of North America, extending eastward to the Mid-Atlantic Ridge and westward to the Cherskiy Range in East Siberia. The plate includes both continental and oceanic crust. The interior of the main continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of crustal material called terranes, accreted to the craton by tectonic actions over the long span of geologic time. It is believed that much of North America west of the Rockies is comprised of such terranes.
The easterly side of the North American Plate is a divergent boundary with the Eurasian Plate to the north and the African Plate to the south forming the northern part of the Mid-Atlantic Ridge. The southerly side is a boundary with the Cocos Plate to the west and the Caribbean Plate to the east. The westerly side is a convergent boundary with the subducting Juan de Fuca Plate to the north and a transform boundary with the Pacific Plate to the south along the San Andreas Fault. On the northerly side is a continuation of the Mid-Atlantic ridge, here called the Mid-Arctic Ridge.
On its western edge the Farallon Plate has been subducting under the North American Plate since the Jurassic period. The Farallon Plate has almost completely subducted beneath the western portion of the North American Plate leaving that part of the North American Plate in contact with the Pacific Plate as the San Andreas Fault. The Juan de Fuca, Cocos, and Nazca Plates are remnants of the Farallon Plate.
[edit] Plate motion
For the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge. The cause of its motion is a matter of ongoing research and discussion. One recent study suggests that a mantle convective current is propelling the plate. [1]
[edit] See also
[edit] References
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de:Nordamerikanische Platte es:Placa Norteamericana fr:Plaque nord-américaine hr:Sjevernoamerička ploča it:Placca nordamericana sw:Bamba la Amerika ya Kaskazini nl:Noord-Amerikaanse Plaat ja:北アメリカプレート no:Den nordamerikanske plate pl:Płyta Północnoamerykańska pt:Placa Norte-americana ru:Северо-Американская плита sk:Severoamerická platňa sv:Nordamerikanska kontinentalplattan zh:北美洲板塊
