Assertion: lithosphere's crust | /r/HasProperty | mafic rocks
Facets:
value: primarily
type: DEGREE
Source sentences:
text: Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.
text: Described by several sources that the oceanic crust is composed of mafic rock or sima that are rich in iron and magnesium also silica (poor).
text: Oceanic crust is primarily composed of mafic rocks, or sima.