Sentences with phrase «old oceanic crust»
Five kilometers down is the beginning of a large magma chamber lying partially within old oceanic crust that had been buried by more than 8 km of eruptive rock layers.
https://www.sciencedaily.com/
As a result, mantle plumes entrain a variable combination of relatively young oceanic crust directly from the subducting slab, older oceanic crust that has been stirred with ancient more primitive material and background, depleted mantle.
The trench is created by the subduction of some of the world's oldest oceanic crust, which plunges underneath the Mariana Isalnds so steeply at places that it is going almost straight down.
Not exact matches
The northwest Pacific crust that is subducting in this area is some of the oldest, coldest oceanic crust subducting on Earth.
The zircons from Mauritius, it turned out, were hundreds or even thousands of millions of years old, although the island's oceanic crust was less than 10 million years old.
Older crust in turn is then forced back down into the Earth's mantle in places where a continental plate meets an oceanic plate.
«Our findings suggest that the primordial crust involved in forming our craton was actually more than 4.2 billion years old and similar in composition to oceanic crust, which is very different from continental crust,» O'Neil said.