For decades, scientists have wondered why there are so many volcanoes in the northern regions of North America. Volcanoes usually occur when one or more continental plates separate or collide.
In northern Canada and Alaska, there are a lot of volcanoes compared to other regions. In Alaska alone, there are more than 40 active volcanoes.
Scientists believe that at one time there was a third seafloor plate in the area, but 40 to 60 million years ago it disappeared under the earth’s crust.
– Sea plates fall back into the Earth’s mantle as they cool. Plates don’t do that on earth, says John Hopper, a professor at the National Geological Survey of Denmark and Greenland, for DR.
When the seafloor plate collides with a continental plate, the heavier seafloor plate will be pushed under the light continental plate. The seabed plate will eventually penetrate inside the earth.
– Very interesting
Scientists would have looked at thousands of measurements of sound waves in the earth and recalculated to find that there was a plate of seafloor beneath Canada and Alaska millions of years ago. They are also said to have reconstructed what the tectonic plates of the Pacific Ocean looked like at the time.
According to the website Technology Explorer there have long been doubts about the missing seafloor plate theory.
Professor Hopper thinks the study is exciting.
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