Assertion: new magma | /r/CapableOf | erupt along spreading ridges
Facets:
value: to form new crust
type: PURPOSE
Source sentences:
text: As old oceanic crust is "consumed" in the trenches (like Holmes and others, he thought this was done by thickening of the continental lithosphere, not, as now understood, by underthrusting at a larger scale of the oceanic crust itself into the mantle), new magma rises and erupts along the spreading ridges to form new crust.