The seismic anomaly in California was lithospheric plate

March 19, 2013. American geophysicists have determined that an underground anomaly in the depths of California is a piece of the lost lithospheric plate. In a press release on the website of Brown University is review articles of scientists, published in PNAS.

Anomaly, called Isabella, located at a depth of 100 kilometers under the central California. It is a lot of cold, hard material not related to the North American plates. New measurements have shown that the anomaly — it is a fragment of the lithospheric plate Farallon extinct 100 million years ago.

Farallon plate located between the Pacific and North American plates. When they started to converge, the Farallon plate was diving under the North American plate and went deeper — into the earth's mantle. Earlier Break off pieces of the Farallon plate is found beneath the earth's crust of the states of Washington and Oregon.

California anomaly is characterized by a high rate of propagation of seismic waves. The appearance of a dense layer at a considerable depth used to be considered the result of delamination — delamination of the lithospheric plates in the earth's crust. Seismic tomography has allowed to establish the similarity between the anomaly Isabella and similar anomalies in Washington and Oregon, which led scientists to the idea of their total membership of the Farallon plate.

As stated by one of the authors, Brian Savage (Brian Savage), this research radically change the understanding of the formation of the western coast of North America. "It will take rethinking the geological history of North America and, without a doubt, the border regions of other continents", — said Savage.

See also: In the Indian Ocean found traces of ancient lost continent

In February 2013 the use of gravity measurements allowed to find the lost continent under the tectonic plate in the Indian Ocean. Open continental plate is called "Mavrica" in honor of the island of Mauritius, near which it was discovered.

Based on: Brown University
Source: Lenta.ru,

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