Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

An aphanitic rock containing about 30% calcium-rich plagioclase feldspar, about

ID: 153375 • Letter: A

Question

An aphanitic rock containing about 30% calcium-rich plagioclase feldspar, about 55% pyroxene, and 15% olivine

A phaneritic rock containing about 20% quartz, 40% potassium feldspar, 20% sodium-rich plagioclase feldspar, a few percent muscovite, and the remainder dark colored silicate.

An aphanitic rock containing about 50% plagioclase feldspar, about 35% amphibole, 10% pyroxene, and minor amounts of other light-colored silicates.

A phaneritic rock made mainly of olivine and pyroxene, with lesser amounts of calcium-rich plagioclase feldspar.

Explanation / Answer

An aphanitic rock containing about 30% calcium-rich plagioclase feldspar, about 55% pyroxene, and 15% olivine=OIivine basalt

phaneritic rock with 20% quartz, 40% potassium feldspar, 20% sodium-rich plagioclase feldspar, =Quartz Monzodiorie

aphanitic rock with 50% plagioclase feldspar,35% amphibole, 10% pyroxene=Andesite

A phaneritic rock with olivine and pyroxene, with lesser amounts of calcium-rich plagioclase feldspar=Dunite