Geologists from the University of California, Berkeley, and the University of Cambridge have proposed a new theory about how the Earth's continents were formed. The researchers suggest that the continents may have been formed by the melting of the Earth's mantle, the layer of rock beneath the crust. This process would have caused the mantle to rise and form volcanoes, which would have eventually become the continents.

The team of researchers, led by Professor Benjamin Hacker from the University of California, Berkeley, studied the composition of rocks from the Earth's mantle and found that they were very similar to the composition of rocks found on the continents. This suggests that the continents may have been formed by the melting of the mantle and the subsequent formation of volcanoes.

The researchers believe that the melting of the mantle may have been caused by the subduction of oceanic crust beneath the continental crust. As the oceanic crust sank beneath the continental crust, it would have heated up and caused the mantle to melt. This process would have been repeated over time, eventually leading to the formation of the continents.

The researchers' findings could help to explain some of the mysteries surrounding the formation of the Earth's continents. The new theory suggests that the continents may have been formed by a combination of geological processes, including the melting of the mantle, the subduction of oceanic crust, and the formation of volcanoes.

The study was published in the journal Nature Geoscience.