In plate tectonics, there are three categories of volcanism: ocean ridge, arc and intraplate. While the origins of ocean ridge and arc volcanism are readily explained by plate tectonics, intraplate volcanism (IPV) is not. The dominant hypothesis for the origins of IPV is by mantle plumes from deep within the interior of the earth.
New research by the University of Cambridge has found evidence in ancient rocks from Greenland that the Earth was at a time almost entirely molten. The study yields information on an important period in our planet’s formation when a deap sea of magma stretched across Earth’s surface and extended hundreds of kilometers into the interior.
According to a study published in the journal Science, for nearly a billion years during our planet’s “middle age” (1.8 billion to 0.8 billion years ago), Earth’s mountains stopped growing while erosion wore down existing peaks to stumps. This extreme mountain-forming hiatus resulted from a persistent thinning of Earth’s continental crust.
