Continental crust was only able to form once Earth's temperature had cooled enough for partial melting of the mantle to occur and produce basalt that was buoyant enough to stay afloat.Before this point small rafts of thin crust formed and remelted in a continuous cycle.What was the composition of these rafts?
A)mafic
B)ultramafic
C)felsic
D)intermediate

Question

Quizplus · Accepted Answer

The early Earth's crustal rafts were ultramafic, composed mainly of minerals like olivine and pyroxene, which are high in magnesium and iron, reflecting the composition of the early mantle.

Continental Crust Was Only Able to Form Once Earth's Temperature