Continental crust forms felsic magma.

Continental crust forms felsic magma.

• A. felsic
• B. mafic
• C. intermediate
• D. ultramafic

Answer: (A)

Continental crust has a felsic chemistry, so the magmas associated with it are felsic. Felsic magma is high in silica and light-colored minerals like quartz and feldspar, and relatively low in magnesium and iron. When it crystallizes, it tends to form light-colored, low-density rocks such as granite and granodiorite, which dominate continental crust. Mafic magma, by contrast, is richer in magnesium and iron and poorer in silica, producing darker rocks like basalt and gabbro that make up much of oceanic crust and upper mantle. Intermediate and ultramafic magmas sit between or well beyond these ranges and correspond to other Earth materials and settings, not typical continental crust.

Continental crust has a felsic chemistry, so the magmas associated with it are felsic. Felsic magma is high in silica and light-colored minerals like quartz and feldspar, and relatively low in magnesium and iron. When it crystallizes, it tends to form light-colored, low-density rocks such as granite and granodiorite, which dominate continental crust.

Mafic magma, by contrast, is richer in magnesium and iron and poorer in silica, producing darker rocks like basalt and gabbro that make up much of oceanic crust and upper mantle. Intermediate and ultramafic magmas sit between or well beyond these ranges and correspond to other Earth materials and settings, not typical continental crust.