- Kula Plate
The Kula Plate was an oceanic
tectonic plate under the northernPacific Ocean south of theNear Islands segment of theAleutian Islands . It was subducting under theNorth American Plate at theAleutian Trench and is surrounded by thePacific Plate . There is a portion of the Kula Plate at the surface in the southernBering Sea .Geological history
The Kula Plate began
subduct ing under thePacific Northwest region ofNorth America during theLate Cretaceous period much like thePacific Plate does, supporting a largevolcanic arc system from northernWashington to southwesternYukon called theCoast Range Arc . There was atriple junction of three ridges between the Kula Plate to the north, thePacific Plate to the west and theFarallon Plate to the east. The Kula Plate was subducted under theNorth American Plate at a relatively steep angle, so that theCanadian Rockies are primarily comprised of thrustedsedimentary sheets with relatively little contribution of continental uplift, while the American Rockies are characterized by significant continental uplift in response to the shallow subduction of the Farallon Plate. About 55 million years ago, the Kula Plate began an even more northerly motion. Riding on the Kula Plate was the Pacific Rim Terrane consisting of volcanic and sedimentary rocks. It was scraped off and plastered against thecontinental margin , forming what is todayVancouver Island . By 40 million years ago, the compressional force of the Kula Plate ceased. The existence of the Kula Plate was inferred from the westward bend in the alternating pattern of magnetic anomalies in thePacific Plate .Name
The name "Kula" is from a Native American word meaning "all gone". [ [http://www.washington.edu/burkemuseum/geo_history_wa/Coast%20Range%20Episode.htm Scroll down to the section "The Farallon Plate Ruptures" on this site] ]
ee also
*
Farallon Plate
*Kula-Farallon Ridge
*Pacific-Kula Ridge
*Izanagi Plate External links
* [http://www.uwgb.edu/dutchs/platetec/kula.htm Reconstruction of the Kula Plate]
* [http://www.washington.edu/burkemuseum/geo_history_wa/The%20Challis%20Episode.htm Kula Plate in the area of the present Northwestern United States]
* [http://www.washington.edu/burkemuseum/geo_history_wa/Coast%20Range%20Episode.htm Kula plate when it separates from the Farallon plate]References
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